Railways as World Heritage Sites
By Anthony Coulls, with contributions from Colin Divall and Robert Lee, 1999
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Railways – an historical introduction
The possibility of designating industrial places as World Heritage Sites has always been implicit in the World Heritage Convention but it is only recently that systematic attention has been given to the task of identifying worthy locations. Any such site must, of course, meet the fundamental criteria specified in the Convention. Yet the particular and peculiar characteristics of industrial sites mean that these criteria need to be developed and refined before they can be of practical use to the World Heritage Committee in the exercise of its powers. This study develops such criteria and illustrates their applicability with regard to just one kind of industrial site, the railway.
What is a railway? According to Dr Michael J T Lewis, the eminent scholar of early railways, it is ‘a prepared track which so guides the wheels of the vehicles running on it that they cannot leave the track’ (Lewis 1974). This definition has the merit of technical simplicity and thus embraces many kinds of transport systems apart from those conventionally known as railways; wheels need not be a feature. But for our purposes the real advantage of the definition is that in referring to aprepared track it draws attention to the fact that railways are built with a specific purpose in mind. That purpose may vary from system to system, but the principle remains the same – a railway is a linear transport feature, the rest is detail.
By the standards of most modern industries railways have unusually deep historical roots. Railways that fit Lewis’s definition existed as far back as the 6th century BC; the Greek Diolkos was a railway with a track made from stone, 6km in length across the Peloponnese, used for transporting ships until the 9th century AD – an extraordinarily long period. Works such as Agricola’s De Re Metallica date the extensive use of railways with wooden rails and vehicles to around the 15th century. Although of great technical interest, individual systems had short lives and were of no significance as anything other than adjuncts to the mining industries. By the 18th century, however, wooden railways began to be used for larger loads and more diverse purposes. Railways developed from mine tracks where people pushed four-wheel trucks of coal, stone, or ore into longer and more complex lines with large wagons and horse haulage. Late in the same century, the change was made in many places to iron rails and wheels. Wooden and stone railways did not immediately disappear, however; indeed, in Britain, the Hay Tor Tramroad was built with stone ‘rails’ at the late date of 1820.
Leaving aside these very early lines, we can date the mechanically worked railway to the first two decades of 19th century England and Wales. These short isolated routes, just a few miles (or kilometres) long, were still usually conceived, financed, built, and operated with the needs of a small number of extractive and primary industries in mind. They shared little beyond a very basic technical similarity with today’s railways. However, they rapidly developed in length, volume of traffic, technical sophistication, and financial and managerial requirements. Most historians agree that with the opening in 1830 of the Liverpool & Manchester Railway in the north-west of England, the prototype of the ‘modern railway’ had arrived: a combination of specialized track, the accommodation of public traffic, the conveyance of passengers as well as freight, mechanical traction, and some measure of public control (Robbins 1998). Conceived principally as a competitor to the carriage of goods by canal, the line tapped a hitherto unsuspected demand for passenger travel. Profits were very considerable and in the generally vibrant economic conditions of the world’s first industrial nation, the railway swept all before it as a means of inland transport over distances of any length. By 1850, Britain enjoyed the benefits of a national network linking most of the centres of population and industry. British engineers rapidly gained employment across Europe, building many of the continent’s earliest and most important railways (Gourvish 1996; Channon 1996; Ambler 1999). By 1907 there were about 200,000 miles (320,000km) of railways in Europe (Robbins 1998).
The British monopoly on railways was to be short-lived. Even as the Liverpool & Manchester was being built, entrepreneurs in the United States were planning the Baltimore & Ohio Railroad, an enterprise on quite a different scale (Stover 1997; Vance 1995; Dilts 1993). Nearly 400 miles (640km) long, the line was promoted by mercantile interests as a way of maintaining the Maryland port’s trade with the mid west, a particular instance of a more general motivation that was to drive much of the early railroad development on the eastern seaboard of the USA. Mercantile rivalries produced a ‘system’ that was far from perfect; breaks of gauge, deliberately engineered to prevent through-running from the lines of one port on to those of another, survived until at least 1900. By 1907, however, there were about 237,000 miles (379,000km) of route in the USA, making it by far the largest single network of railways in the world (Robbins 1998).
The place of the railway in the history of industrialization is assured. Economic historians might disagree over the precise contribution that railways made to economic growth in the industrializing nations of the 19th century, but all recognize the steam railways’ critical role as the dominant form of inland transport for any but the shortest of journeys (eg Szostak 1991; Ville 1990). Railways rapidly developed as the largest and most complex examples of socio-technical systems that the world had known: the political, financial, business, and managerial structures that developed to meet their novel requirements later influenced the growth of large-scale corporate business, particularly – but by no means exclusively – in the USA (Dobbin 1994; Chandler 1990) The railways’ advantages of speed, capacity, and economy made them more than mere instruments of industrial and business development, however. Culturally their impact was huge. In particular the sensibilities of societies that had never known travel at speeds above that of a galloping horse were irrevocably changed by the coming of steam locomotion. In Europe and the USA, the railway came rapidly to stand at the very focus of that mixed feeling of awe, wonderment and apprehension that historians have called the ‘technological sublime’ (Nye 1994; Wosk 1992; Danley & Marx 1990; Schivelbusch 1986).
The railways’ influence was not only felt in those countries that industrialized first. By the 1850s the cutting edge had spread well beyond Europe and even the USA. Railway construction began in the colonies of the European powers and the South American republics, with the first lines opening in Brazil and Chile (1852), Argentina (1857), India (1853), Java (1864), and Australia (1854). The Canadian Grand Trunk Railway, started in 1852 and intended to link the Atlantic seaboard with the Great Lakes, was at the time the longest railway planned in the world. Its promoters combined politics and economics in their reckoning: the line was built with the combined intention of binding the eastern Canadian provinces together economically and of reducing the influence of the USA (Lee 1998; Legget 1973). The construction of the Trans-Siberian Railway at the end of the 19th century provided a similar national link for Russia. By 1907, there were 168,000 miles (268,800km) of railway outside Europe and the USA, built at a cost of nearly GB£1.5 billion (Robbins 1998).
All of these railways were part of a wider, and much larger and more complex phenomenon, namely the spread, prior to World War I, of European imperialism around much of the world. Railways were not the only technology to further the process of imperialism: the steamship, the telegraph, and new medicines such as quinine were also important. However, railway building and imperialism were, quite simply, interdependent. Railways often transformed the way in which an imperial power exploited the resources of a colony – for instance, by opening up a hinterland – and even, according to some historians, permitted the development of a new kind of ‘informal’ or ‘railway’ imperialism in which the struggle for explicit political control was relinquished in favour of more subtle kinds of influence (Davis and Wilburn 1991). Even those countries which escaped direct rule from Europe – Latin America, the Ottoman Empire, China, Japan, and Thailand – fell in varying degrees under the economic and political domination of the occidental powers. The projection of the trans-Siberian railway to the Pacific, for instance, combined with that of the Berlin-Constantinople line to Baghdad, led the European powers to partition the Chinese and Ottoman empires in terms of exclusive railways rights. Imperial strategy in Asia was directly connected with the military, political, and economic balance of power in Europe (Lee 1998).
Imperial penetration had always begun from ports, but until the coming of the railway the influence of the European powers rarely extended far inland. The railway permitted comparatively easy access to the hinterland; imperialists used railways to integrate and annex territory, and to exploit the resources of the regions surrounding the ports they controlled. The obstacles that had to be overcome were varied and often considerable. They might be political – the resistance of traditional élites or the populace, or that of another rival European power, such as the chimerical French threat to British control over the Suez route to the East that led to the construction of the Uganda Railway. Once these challenges had been met, geography often forced civil engineers to scale ever greater heights, both metaphorically and – sometimes – literally. Their engineering feats became all the more impressive as physical and political boundaries were pushed farther back. Tunnels, bridges, viaducts, cuttings, and embankments, all were developed to take the railway into places which previously had been inaccessible to any but the most determined. Whatever the difficulties, or for that matter the degree of success, the aim remained more or less constant: from Manchuria to Argentinian pampas, from the Great Lakes to the African veldt, from Yunnan to the Australian bush, the creation of a hinterland was the chief motivation (Lee 1998).
Colonial railways were thus an essential part of the spread around the world of the economic processes, ideas, and institutions of the European powers: the production of new foodstuffs and raw materials to feed the industries and peoples of the West, new populations to produce them, new patterns of land ownership, and new legal codes to make the conquered lands safe for investment and exploitation. In European-settled parts of the world, most communities desired the coming of railways as the key to prosperity, while every government wanted them for national development. However, railways were expensive, and the direct financial returns in most parts of the world uncertain, even in the longer term. Typically, railways outside Europe and the USA were joint ventures between European private investors and the governments of the host countries which guaranteed a fixed rate of interest on the borrowed capital. Thus many states fell into financial dependence on the European banks and stock exchanges, mortgaging lands and taxes to pay for railways that were costly both to build and to operate. Nor did contemporaries often draw attention to the social and environmental downside of the technological triumph of the world-wide spread of railways: the exploitation of humans and resources to an unprecedented degree. More commonplace was an almost missionary fervour, emphasizing the role of the railway and (European) engineers as harbingers of ‘civilization’ (Lee 1998). Whatever the social and economic benefits that later accrued – and we should not forget those that were difficult, if not impossible, to reckon within the conventional accountancy of the day, such as the provision of the infrastructure of public utilities – the initial cost in human life and misery was all too often appalling high (eg Kerr 1995).
The ‘great’ or ‘golden’ age of railways – in the sense that they virtually monopolized inland transport – was over in most countries by World War I. Certainly by the middle of the 20th century most of the world’s railway network was in place and on the whole the story since then has been one of slow decline, at least in terms of route mileage. Development continues on existing routes, however, and new lines are still built. Perhaps the most notable of these in the last forty years is the Japanese Tokaido line, opened in 1964 for the high-speed Shinkansen. This led the way for other countries to develop fast main lines solely or mainly for the use of express passenger traffic; the French Lignes à Grande Vitesse are excellent examples of this. Not all new construction is of this kind, however: in some parts of the world (China is a good example) it is still considered worthwhile to build conventional railways of a very considerable length in the pursuit of economic development and social change. Virtually all these new systems run on standard gauge (4ft8½in/1435mm) track, and although the materials, traction, and principles of management employed almost invariably differ from those of the pioneering railways, the same basic technical principles look set to take the mechanically worked railway into its third century.
Railways as World Heritage sites – some theoretical and practical considerations
What makes a railway potentially a World Heritage site? Since all heritage is intimately bound up with the creation of collective identities, be these at the local, the regional, the national, or the global level, it is clearly impossible to expect a single, straightforward answer (Lowenthal 1997). In many countries the railways’ past enjoys a high public profile, reflecting the part that they have come to play in the formation of communal identities over the last 200 years. Indeed, in some parts of the world – Britain is arguably the most extreme example, although the USA is probably not far behind – the level of lay interest in railways is such that the volume of research emanating from this quarter far outweighs that from academic sources. This brings both advantages and disadvantages. Some lay work achieves academic standards of scholarship, and more generally there is an enthusiastic commitment to search out the kind of detail which can prove useful in developing a more rounded appreciation of particular railways or sites. Less positively, lay enthusiasms are sometimes so passionate that it can be very difficult to reconcile conflicting points of view over the merits of locations that might be thought worthy of designation as World Heritage sites.
Nevertheless, the fundamental criteria set out in the World Heritage Convention must provide the basic tools for any study that hopes to achieve consensus. The intention here is to demonstrate that these basic criteria can be developed in ways that will enable the World Heritage Committee to come to a reasoned judgement on those railways and related sites nominated for designation by the national parties to the Convention. We also offer some illustrative examples of the relevance and applicability of our proposed criteria.
Our fundamental assumption – and it is one that is shared by virtually all those who have commented on our proposals – is also one common to all modern historiography of large-scale technologies: that railways are above all socio-technical systems in which it is ultimately impossible to separate out the ‘social’ and ‘technical’ aspects. While it may prove desirable, or indeed necessary, to do so for analytical purposes, a proper appreciation of the historical significance of any particular railway will only be gained by seeing it in the round; as both the product of, and an influence on, wider social circumstances.
This perspective stands in sharp contrast to that of many railway enthusiasts or ‘railfans,’ who too often sees locomotion as being all important – much being made of steam operation in particular – while the specialist infrastructure, the social organization, and the wider historical context of railways’ development are given less weight than they deserve. There is also the practical difficulty that in several countries locomotives and rolling stock have been designated as national monuments. The designation of such items as World Heritage sites is probably inappropriate, not least because of the likelihood of an exceedingly large number of nominations. Permitting such classes of objects for designation would also raise many further issues, not least those of ownership and access, which it is impossible to address in this study. The criteria developed here are intended partly to correct such ‘lococentrism,’ facilitating the undertaking of more detailed studies that will comprehend individual railways as fully contextualized sites.
The history of railways has long been the subject of comparatively disinterested academic enquiry, resulting in a body of knowledge which comprehends the rich diversity of railway development around the world. It is by reference to this stock of work – incomplete or inadequate though it might be with regard to certain periods, subjects, or geographical areas – that there is the best opportunity of building consensus around a set of criteria for World Heritage listing. Such criteria must enable the universal elements of the world-wide evolution of railways to be identified. Once agreed, these criteria may be used by the World Heritage Committee to establish the ground rules for the preparation of the detailed studies of individual sites that the nominating parties must submit. We hope, too, that the criteria will assist the Committee in coming to its own views on the merits of particular locations.
This study is concerned with the development of criteria for World Heritage status that can be applied to surviving routes (whether or not they are still operating as railways) and other features on the ground that can either be followed or visited, at least in part. Some overlap with other industrial sites and transport systems will be inevitable. The routes of railways, canals and roads were often physically linked. Railway companies frequently came to own canals, while the transfer of technologies between the different modes occurred regularly, especially during the construction phase: railway lines were built by teams of men known in Britain and elsewhere as ‘navvies’ – derived from the name ‘navigator’ that groups of labourers acquired while building inland waterways. Railway workshops benefited from advances in other industries, and in turn were able to influence other transport technologies through the development of the machines and rolling stock they produced. Similarly, railway technologies were transferred across the world. The first steam locomotive in the USA was built in Stourbridge in Britain in 1829. The Americans then adapted the technology to their own circumstances. This process was repeated between various countries over the next century or so, and has now come full circle, with Japan leading the development of high-speed trains (the Shinkansen) and Europeans following suit in the last thirty years.
The remains of early railways – that is to say, those which date from before about 1830 – will require particular consideration by the Committee. They deserve recognition as precursors of the later, more influential systems, but there is a real danger that important sites will be missed as our understanding of the international significance of these lines and their remnants is not, with one or two exceptions, as deep as it might be. They should also be taken as special cases because their remains are often quite different from those of railways of more recent construction, tending to have more in common with sites of considerable antiquity. This is true of some of the very early mine railways and associated equipment, some of which is now preserved in museums; unfortunately, having been taken out of place and context this cannot now qualify for World Heritage status. But even if they do not score particularly highly according to the general criteria proposed here, some early railway sites are surely worthy of consideration on other grounds. For example, civil engineering from the classical period helped the builders of the Causey Arch on the Tanfield Waggonway in County Durham (England). No span as large as this had ever been constructed in 1727, so the builders drew on examples from the ancient world to see how it might be done. One could argue that the resulting structure, demonstrating as it did the practicality of large-scale masonry arches, was as significant for the subsequent course of the history of inland transport in general (canals and roads as well as railways) as was, say, Coalbrookdale and the Ironbridge Gorge for industrial history.
There are other issues, particularly those of authenticity and conservation, which clearly must be addressed by the World Heritage Committee but which we do not attempt to deal with in any depth here, chiefly because they do not raise questions that are fundamentally different from those involved in any number of other areas of heritage (Burman 1997). No operating railway can be wholly authentic from a strictly historical point of view; items wear out and are replaced, methods of organization and operating are adapted to changing circumstances. However, arguably continuity through change is part of what makes a railway landscape or location: railways are by their very nature evolving socio-technical systems. Indeed, the drive to modernize and become more efficient appears to be an imperative of modern railway management world-wide. The key challenge is to identify just what it is about a railway location that makes it worthy of World Heritage status. A focus on the purely physical aspects of structures or technologies arguably makes it more likely that a site will be deemed ‘inauthentic’ as modernization proceeds than if equal (or greater) weight is given to the historical continuity of a railway’s socio-economic functions. This is not an argument for any weakening of the imperative of good management of those historic features which do remain. Co-operation between railway operators and conservation bodies can make sensitive development possible and ensure that the integrity of sites is maintained, as the example of the British network over the last two decades shows (Burman & Stratton 1997). It is, we suggest, preferable to have a viable and useful railway rather than one which faces an uncertain future.
The proposed criteria for
internationally significant railways
The following criteria essay a means of identifying the universal aspects of the very diverse development of railways around the globe. They are derived from four principal sources:
- the consensus emerging among parties interested in the wider issues of the designation of industrial sites and locations, particularly as recorded in the earlier studies on canals and bridges undertaken for the World Heritage Committee;
- the views of those attending an international conference held in March 1998 at the National Railway Museum, York (UK);
- the opinions of those correspondents who were unable to attend in person (lists of those within the second and third categories are given in the Appendix);
- our own, imperfect understanding of the current state of knowledge of railway history internationally.
The proposals are not listed in any particular order of merit: indeed, it will be apparent from our earlier comments that no such ranking would be appropriate
CRITERION 1: A creative work indicative of genius
Something like this criterion has long been applied in the informal ranking of railways around the world. It fits well with the long-standing approach to history that seeks to identify ‘Great Men’; railways are technical systems designed and built by engineers, therefore it should be possible to identify the world’s great railways with the great engineers.
Understood in this way the criterion is most easily applied to railways whose chief engineers were highly innovative in their approach and treatment of difficulties; the Great Western Railway under the Englishman Isambard Kingdom Brunel, for example, or the spectacular Semmering Railway through the high Alps, built by the Austrian Karl Ritter von Ghega.
Modern scholarship suggests that the criterion should be interpreted more widely, however. Biographers’ and historians’ perceptions of the great engineers have shifted quite markedly in recent years: the kind of heroic perspective favoured, for example, by the 19th century English writer Samuel Smiles is no longer regarded as adequate. While not wishing to deny the great skills and abilities of individual engineers such as Brunel or the Stephensons, scholars tend to stress the co-operative nature of railway building (Jarvis 1994). Perhaps, then, sites should be taken as memorials not only to the engineers ultimately responsible for their design and construction but also all those others – many of whom will never be known – with a hand in bringing them to completion. Moreover, with a highly complex socio-technical system like a railway, many skills and abilities in addition to those of the engineer were required. Should we not, for instance, look for genius in the financing and managerial organization of railways? In this way sites could come to symbolize the wider societies and cultures that gave them birth.
CRITERION 2: The influence of, and on, innovative technology
The primary purpose of a railway is to provide a transport service for goods or passengers. But technology serves a critical role in all of this, and thus it is proper that the role of innovative technologies should be acknowledged in any set of criteria for World Heritage status.
The technology of the railway includes its course – the trackbed, embankments and cuttings, engineering and architectural structures, and the constructional methods employed. The transfer of technologies from and to other industries and transport modes should also be borne in mind, particularly the imaginative application of new materials and constructional techniques, such as those associated with the move from iron to steel from the 1860s, and experimentation with structural concrete towards the end of the 19th century. Likewise, while early railways were built largely by hand, mechanization was rapidly introduced, particularly in those countries such as the USA where labour was in short supply. The mechanical technologies of locomotives and rolling stock (passenger coaches and goods vehicles) are just as relevant, although less easily acknowledged in any study that focuses on fixed sites and locations. Nevertheless, places relating to the construction and maintenance of vehicles may be considered. Fixed motive power in the form of winding engines or water balances may also be relevant: for example, that important English railway, the Stockton & Darlington, originally used stationary haulage engines where the gradient was thought too steep for locomotives.
The criterion of innovative technology may apply to different types and periods of railway development. International transfers of ideas took place very early in the history of the mechanically worked railway. Early Blenkinsop and Murray locomotives from Britain were exported and used in Germany in the 1810s. Similarly, the Festiniog Railway in Wales pioneered the use of steam power on narrow (less than 4ft8½in or 1435mm) gauge in the 1860s. The use of a gauge of 2ft (600mm) meant that it was possible to construct a railway more cheaply and in more inhospitable terrain than might otherwise have been the case. Many engineers from overseas were inspired by what they saw and took ideas and principles away with them to use in their own countries: the Darjeeling Himalayan Railway in India tackled mountainous country in much the same way as the Festiniog did. International transfers were a feature of much later periods as well. In this century, for instance, the fundamental principles of the Japanese Shinkansen have been applied to European high-speed operations.
Technical matters always need to be taken in context. Modern historiography of technology typically requires an interdisciplinary approach: social, economic, environmental, and political factors among others influenced technical change and development on the railways (eg Rosenberg & Vincenti 1978). To exclude history from technology (or for that matter technology from history) is to miss a vital part of the story: technical change has both informed, and been informed by, social and economic change around the globe.
CRITERION 3: Outstanding or typical example
There is a place for the designation of sites either because they have always been outstanding in some regard or because, although once commonplace or typical, they have become special simply by virtue of their survival. Particular historical events and associations will help with the identification of outstanding locations: originality and authenticity might be factors justifying the designation of railways on the grounds of typicality.
There is a case, for instance, for designating an example of a secondary main line which, although not outstanding according to any of the other criteria, would be of international importance because of its historical integrity – still fulfilling its transport purpose while having an excellent heritage content. The Newcastle & Carlisle Railway in England might fall into this category. Opened in 1836 and still in use, its role as secondary route has helped to ensure the survival of many structures illustrating the line’s development from its earliest days. Similarly, one mountain railway might be selected as typical from among the many in, say, Switzerland and Austria.
Particular structures or locales may also be seen as typical. Something such as a steam-locomotive servicing depot which remains complete with all its infrastructure (water tower, shed, turntable, and fuelling facilities) may be worth designating as a symbol both of the technology of the railway and as a place of work. As such places become much rarer, the precise location of survivors becomes of less importance than the power of what remains on the ground to stand as symbols for what was once commonplace around the world.
Passenger stations are a particularly attractive kind of structure from both perspectives. Yet they are also difficult to assess. There are internationally many fine stations in terms of architecture and historical significance, and it would be very easy to designate a great number (Richards & MacKenzie 1986). Perhaps the best option would be to include large termini and through stations in a separate category of World Heritage sites embracing urban structures in the context of townscapes. Smaller stations, on the other hand, could be considered, where appropriate, as part of the case for a complete railway.
CRITERION 4: Illustrative of economic or social developments
Despite our strictures to the contrary, a case could be made for saying that this is the principal criterion by which sites should be judged. After all, railways were built to perform a transport function, and this basic function has served many political, social, economic, and cultural purposes in addition to fulfilling people’s desires to travel and trade. However, this very diversity brings its own challenges. As we indicated in the introduction to this study, the railways’ influence on social and economic life has not been the same around the world, presenting us with the challenge of identifying just what it is about a particular site that represents a universal experience. The problem is made even more complex by the fact that opinions over the normative value of what the railways enabled could – and still do – differ considerably.
Even if one leaves the problem of these conflicting evaluations to one side, there is the added difficulty that most historians agree that it is extremely difficult to isolate the wider effects of railway development on the complex societies of Europe and North America. Claims that the railways were single-handedly responsible for the take-off of industrialization, for example, simply do not stand up to the rigour of modern scholarship. This does not mean, of course, that railways were irrelevant or unimportant, but it does imply that any claims for the designation of particular sites on the basis of this criterion need to be justified by means of careful studies rather than mere assertion.
The difficulty of assessing the direct social and economic contribution made by railways can be alleviated in the case of one, admittedly somewhat unusual class of settlement, the railway town or locale. These were places that the coming of the railway called directly into being, either for its own purposes such as the development of workshops or by allowing the exploitation of resources that previously had been hampered by poor communications. Places such as Crewe or Swindon in the United Kingdom, or the Eveleigh district of Sydney, New South Wales (Australia), are good examples of the former kind and could be found almost anywhere there were railways. Detailed studies often reveal that railway companies adopted all kinds of policies designed to secure social cohesion among their workers, perhaps by the paternalistic building of housing and other amenities for their workers (eg Drummond 1995). Settlements of the latter type, by contrast, were far more common in North America or those parts of the world that fell under the influence of the imperial powers than they were in Europe.
This criterion has the advantage of admitting for consideration several important types of railway that would rarely qualify on other grounds. Suburban, street (tramways), and underground railways affected the growth and social development of many urban places. The role of railways as lines of communication along which suburban settlement spread is illustrated very well, in Britain at least, by London’s ‘Metroland’ – the developments of the 1920s and 1930s spurred by the Metropolitan Railway. This pattern had earlier been found in many large towns and cities across the world, from the Paris Métro to the overhead urban railways (‘El’s’) of New York, Chicago and elsewhere. Street railways or tramways played a critical role in the development of many major cities, some of which, like Los Angeles, are now almost completely dominated by road transport; perhaps consideration should be given to designating one of the surviving great urban tramways. Even where railways were not critical for the movement of people and goods inside the town or city, the siting of passenger and goods terminals usually had significant and long term consequences for the urban morphology (Bond & Divall 1999).
None of these criteria can be allowed to stand apart from the others. Since railways are socio-technical systems, all the criteria must be applied to each site that is nominated for World Heritage status. Of course, particular railways will be deemed more significant on certain grounds rather than others. One location might be of great technical significance, another of considerable social or economic value. How then can one weigh the two in the balance? Unfortunately there can be no neat formula: there is – perhaps fortunately – no heritage equivalent of the quantitative approach of, say, cost-benefit analysis. By choosing one railway site as a World Heritage site over another we also choose, in some small way, to make ourselves.
The criteria in practice – some railways of note
The railway sites analysed here serve to demonstrate the applicability of the proposed criteria and to show, in outline, the kinds of factor that the World Heritage Committee might consider asking States Parties to the Convention to bear in mind when making their nominations.
Although we have tried to demonstrate the relevance of the proposed criteria to a range of sites, both in terms of geographical spread and type of railway, these brief studies are only illustrative. In particular, the inclusion of any location does not imply that in our opinion it should – or should not – be considered as a World Heritage site. The same applies, of course, to the many potential sites that are not mentioned here. It follows that these studies are listed in no particular rank.
Case 1: The Moscow Underground
Urban railways, including tramways or street railways, rank among the least regarded but most significant of locations from a social and economic perspective. This system, described as the ‘Showpiece of the Revolution,’ is the most heavily used underground railway in the world. Planned as a unified whole, unlike those in most other cities, it carries about nine million passengers a day over nearly 200km (125 miles) of track. The first line opened in 1935, and others have followed, all part of a plan to provide an efficient means of moving the people of the vast city of Moscow. Reflecting the political ideology of the time, the Underground was built on a grand scale, so as to be a prestige feature as well as a practical solution to a transport problem. The earlier stations show that no expense was spared on fine design and ornamentation. One writer has described the system as ‘the most beautiful underground railway in the world’ (Nock 1973: 182).
As an outstanding mass transit railway, the Moscow Underground exemplifies the social and economic criterion for World Heritage status. It is also a masterpiece indicative of genius. Here, however, one encounters a problem commonly found with outstanding achievements of modern industrial society: there is no single name which can be picked out as responsible engineer. This need not matter, however, if one accepts that a site or location may reflect the wider cultural context within which it was built. The Moscow Underground is significant partly because it was an elegant solution to a pressing transport problem, relieving the surface transport systems of bus and tram of much of the commuter pressure which had built up as the city expanded. It is also remarkable as a symbol of the modernization of Russia under the Soviet regime (under Tsarist control, plans for an underground had been abandoned in 1900).
The many kilometres of railway follow the historic development of the city, with ten lines radiating out in all directions from the centre and connected on the periphery of the city by a circular route. Although the plan for the system was drawn up as one, the building of the routes took place in stages, each line reflecting the political and ideological development of the Soviet Union. Some have even suggested that the Moscow Underground is the former USSR in microcosm.
Construction involved the use of several unusual and pioneering techniques to overcome a number of geological difficulties. These included such practices as chemically solidifying the earth around the tunnel profile and freezing the ground in order to permit excavation, then lining the tunnel walls with concrete (itself a difficult process as concrete requires a certain amount of warmth to set). Even the removal of the spoil from construction caused problems, and it is no wonder that the first line’s building alone occupied 30,000 men.
The stations are quite unparalleled anywhere in the world. The main objective was to provide friendly and convenient spaces for the public which avoided any suggestion of being ‘underground’ (considering the tyrannical nature of the Stalinist regime there is, to say the least, a considerable historical irony here). No attempt was made to standardize designs, and some highly individual and striking buildings resulted from the ideas of leading Soviet architects. The stations were designed to impress, and they do impress. An air of opulence characterizes the majority of stations, which are far removed from anything which one might find as an underground station elsewhere in the world. With many stations having walls of marble in various hues, glass ceilings, wide platforms, and soft diffused lighting, the Moscow Underground is truly an outstanding example of its type. Compared with other underground systems, it is sui generis, yet for all its grandeur, it is extremely practical and functions well. In addition, partly owing to the Russian practice of shift working, overcrowding is minimal and the vast stations always give the impression of effortlessly absorbing traffic even at the busiest of times. Cleanliness and efficiency continues to be of paramount importance, achieved partly by lavish staffing.
A more beautiful and inspired array of media (architecture, sculpture, painting, and decorative arts) as a vision of functional public space would be hard to find. The Moscow Underground as a whole exemplifies many of the criteria for World Heritage status. The first line, built from 1932 to 1935, is perhaps the single best example. As a high point of the Soviet avant-garde, its combination of modernism and practicality continues to serve the Russian city of Moscow today.
Case 2: The Semmering Pass, Austria
It was in Europe that railways first began to penetrate really mountainous country. The pioneer mountain railway was, in many respects, the Austrian line over the Semmering Pass built between 1848 and 1854. It also reasonably can be described as the first ‘imperial’ railway, linking as it did the capital of Vienna with Austria’s Italian possessions to the south. Admittedly, though, its function was not to extend the economic and political reach of new and dynamic empires, as the colonial railways built later in the century were, but to prop up a moribund and decaying one.
The Semmering line, engineered by Karl Ritter von Ghega, runs from Gloggnitz to Murzzuschlag, crosses the high Alps in a 42km (26 mile) long section known as the Semmering Pass. It still forms part of the railway from Vienna in Austria to Italy and Slovenia. The Adriatic port of Trieste had special importance as part of the Austro-Hungarian Empire: since it was the only access the state had to the sea, an efficient railway connection was of the utmost importance. An Imperial Edict for a line over the Semmering was passed in 1844, but the original plans were shelved after doubts over tunnelling. The revolution of 1848 in Vienna changed the political climate and increased pressure for the line’s construction. Designed for locomotive operation throughout, the railway became a prototype for mountainous railways and led the way for others to cross the Alps by rail.
Its civil engineering neatly demonstrates the relevance of the technical criterion for World Heritage status. For example, new techniques had to be developed to cope with the difficult mountainous circumstances when little or no mechanical assistance was available; viaducts had to be constructed on both curves and gradients together, for instance. Surveying was all done from the ground, through crags, ravines, and heavily wooded slopes. How von Ghega managed to engineer a line through this on a steady gradient is little short of marvellous. Yet in other ways the railway was conservatively engineered. As far as materials were concerned, von Ghega rejected the use of iron and steel as a matter of principle; the result was sixteen brick and stone viaducts. Nevertheless, construction was an organizational as well as a technical achievement. At the peak of building, some 20,000 men were employed. The building of the Semmering Railway was very much a ground-breaking exercise, after which nothing seemed impossible: it was claimed that there was nowhere that a railway could not be built after this. The line was quickly recognized as an outstanding example of engineering; once it had been fully opened, sightseers came in large numbers to view the railway and the landscape through which it passed.
The line also exemplifies the way in railways must be treated as technical systems. The line was planned by von Ghega to operate with steam locomotives. A competition was held in 1851 to find the most suitable type of engine, an approach similar to that adopted by the directors of the Liverpool & Manchester Railway at Rainhill in 1829. The result was that mechanical engineers were spurred to design engines that met the arduous requirements of the Semmering Pass and the railway was run by locomotives in its entirety. Steam worked for a century, but electrification took place between 1956 and 1959. This was by no means an early use of the power, but was significant for the amount of extra traffic which was accommodated.
Apart from this and the construction of a new, second Semmering tunnel from 1949 to 1952, today’s railway is still substantially that designed by von Ghega. The continued operation of the line is a sound testimony to his engineering genius.
Case 3: Baltimore & Ohio Railroad, United States of America
This was the first railroad of any length in the USA, being chartered in 1827. Inspired by the British example of the Stockton & Darlington Railway, its opening was virtually contemporaneous with that of the Liverpool & Manchester. Described as ‘America’s pioneering railroad’ (although it was neither the first railroad in the continent nor the earliest steam-powered line), it was the USA’s most ambitious early transport project and its most successful. The B&O is an excellent example of the inspirational transfer of technology from one country to another (Harwood 1994: 48).
Given the huge differences in social, political, economic, and geographical circumstances between Britain and the USA, the English examples finally proved to be of limited practical relevance to the story of the B&O and indeed that of the wider railway system of North America (Robbins 1998: 115-121). Nevertheless, the international dimension was crucial in the early days. The B&O was the railway on which, in 1830, steam locomotion was first applied in the USA with any measure of success; the engineers involved in the project had visited Britain to gain ideas, several having attended the Rainhill Trials. Similarly, the extensive use of brick and stone in the line’s structures shows how ideas were taken from the British model. The B&O’s bridges were strongly built from the outset to carry heavy traffic and steam locomotives, and many are still in use today, including the Thomas viaduct of 1834 which, at the time of its construction, was highly unusual in being built on a curve. This structure closely resembled the Liverpool & Manchester Railway’s Sankey Brook viaduct and is a good example of the ‘design and build’ policy adopted by the railway’s promoters. The structure was designed and constructed by Benjamin Latrobe, one of several engineers responsible for the B&O. Many of the railway’s civil engineers went on to form the core of the railway engineering profession in the USA, the line itself being described as a ‘lecture room to thousands’ (Dilts 1993: 2).
The railroad also confirms the significance of social and economic criteria for judging a site’s standing as a World Heritage site. By the time it reached the Ohio river in 1857 the B&O ran for 380 miles (600km) and it was a key factor in the development of the USA. Planning and engineering overcame natural obstacles in the form of mountain wildernesses, and the successful opening of the line in stages provided the impetus for further progress, not least the development and extension of the Western frontier. The entrepreneurs promoting the railway were simultaneously guarding their own interests while expanding the young nation’s physical and economic horizons. The building of the railway revitalized Baltimore as a port, spurred its industrial development and contributed to the reshaping of its urban geography, as well as its financial, educational, and cultural institutions. By allowing faster and cheaper distribution of goods, the line contributed to Maryland’s economic expansion, particularly aiding the growth of the state’s iron and coal industries. However, the line was not just of regional importance. Even at the time of its construction, the railway was considered a national endeavour. It became the first leg of the US railroad system, with Baltimore its base - ‘the birthplace of American railroading.’
Case 4: The Great Zig Zag, Australia
As the 19th century progressed the focus of railway construction shifted beyond Europe and the United States as the age of new imperialism established itself in some of the more far flung parts of the world. Australia’s first railway opened in 1854, the Zig Zag following in 1868.
The Great Zig Zag brought the main western line of the New South Wales Railways over the Great Dividing Range of the Blue Mountains into the Lithgow Valley, some 94 miles (150km) west of Sydney. It was the means chosen by the railway’s engineer, John Whitton (1819-1898), to overcome the greatest natural obstacle on this, the first railway to penetrate into the interior of Australia. Whitton would have preferred to use a long tunnel, but, as his immediate superior, John Rae, the Under-Secretary for Public Works, reported, ‘the low state of the country’s finances compelled him to adopt zigzags, instead of tunnels, or abandon the works entirely (Rae 1873: 2-3).
Whitton is the only 19th century Australian engineer whose work F A Talbot discussed in his 1911 account of the ‘railway conquest of the world’ (Talbot 1911:177-80). Moreover, Whitton’s greatest work was completed earlier than Talbot describes. When Whitton ‘conquered,’ to use Talbot’s terminology, the Great Dividing Range and thereby opened up the interior of the Australian continent for intensive exploitation, the technology which allowed the railway to spread across the world did not yet exist. Whitton’s transmontane lines were built in the 1860s, by hand, from iron rails, and with bridges of stone or wrought iron. Dynamite and steel were not as yet being used in railway applications. Whitton had to use the expensive and relatively cumbersome technology of the pioneer English railway builders, but in a colony which was remote and impecunious and across terrain far more inhospitable than anything in England, if not quite as forbidding as that confronting later railway builders in Africa and Asia. At the time, only in India and Canada were railway builders attempting anything quite as ambitious, and in those places greater population and imperial political imperatives meant that resources were available on a far more lavish scale than Whitton could ever command.
Whitton’s English training meant that he felt obliged to build his railways solidly: every one of his three cast-iron plate bridges and his numerous sandstone arched viaducts of the 1860s still stands, some still carrying heavy rail traffic. Whitton’s two great compromises were to use grades far steeper than were the norm on English main lines of the 1860s, 1 in 30 in the down direction, 1 in 42 on the up, which carried the bulk of the heavy export traffic, and to resort to zigzags where the topography was particularly poor. There were two on the western line, one of which (at Lithgow) is particularly spectacular and survives intact.
The Great Zig Zag involved the construction of three elegant sandstone viaducts, one of five and two of nine arches; cuttings up to nearly 80ft (24m) deep; and two tunnels, one of which was opened out into a cutting before completion. The work was difficult and expensive. The 15 mile (24km) contract which included the Great Zig Zag cost £328,284 or £21,886 per mile, very expensive indeed for a single-track railway whose land costs were zero. The precipitous nature of the slope down which the zigzag was built combined with the unpredictable, often savagely cold and windy climate of the valley, made the task a hazardous one. The line descended from its summit of 3658ft (1114m) at the portal of the Clarence tunnel into the valley.
Railway operations began over the Great Zig Zag on 18 October 1868, effectively opening the interior of New South Wales to intensified European settlement, transforming it from a gigantic sheep walk into a rich agricultural country. The subsequent history of the line is as interesting as its construction. In short, it rapidly became a casualty of its own success. New industries were spawned by the railway, notably the cultivation of wheat and coal mining. These were far heavier commodities than the wool and gold which had dominated the economy of the interior of Australia before the coming of the railway. Traffic soon grew to the extent that the zigzag was a bottleneck. Its bottom road was duplicated in 1880 and a series of crossing loops installed. The Great Zig Zag also did much to stimulate tourist traffic to the region, an early and unusual instance of a railway creating its own traffic. As John Rae succinctly observed, ‘zigzags, though not so convenient for traffic as tunnels, are more picturesque in appearance’(Rae 1898:11). A tourist platform was built at Bottom Points and as early as 1881 a public reserve of 550 acres (223ha) was proclaimed around the Great Zig Zag, ensuring the preservation of the wild grandeur of the site.
In 1893 the decision was taken to eliminate the zigzag, but work did not begin until 1908. Construction of the zigzag deviation took a little over two years and involved the boring of ten tunnels with a total length of nearly 3km. The deviation, opened on 16 October 1910, continued to use the zigzag’s bottom road, with its 1 in 42 grade and 8 chain (160m) radius curve, the sharpest on any main line in New South Wales. Electrified in 1957, the bottom road continues to carry a huge traffic, including coal trains loaded up to 4100 tonnes and frequent passenger trains. Until 1975 the viaducts and tunnel of the middle and upper road were cared for by the Zig Zag Trust, but in that year a 3ft6in (1067mm) gauge line, on which former Queensland and South Australian Railways equipment operates, was laid on the middle road. In 1988 the line was relaid on the top road and through the Clarence tunnel, and passenger services on the revived railway began operating on 364 days per year, even if on a different gauge from the original line.
Thus the Great Zig Zag has remained partially in use (along its bottom road) and fully intact throughout its history. The revived operations on the middle and top roads are not authentic, inasmuch as they are on a different gauge and use rolling stock built after 1910 (passenger cars from the 1920s, steam locomotives from the 1950s, and diesel railcars from the 1960s). Nonetheless, the operators have taken great care to build authentic line-side structures, including a magnificent timber signal box at Bottom Points, and this important site is not just very well maintained, but extensively visited and enjoyed by about 250,000 people each year. Most are ignorant of just how significant in world terms the site is, given the early date of its construction and its unique combination of solid British civil engineering, typical of the world’s earliest railways, with a structure as unconventional and more usually associated with much lighter railways as a zigzag. Apart from the reversing station on the Bhore Ghat section of the Bombay-Poona line of the Great Indian Peninsula Railway, the two zigzags on this line were the first such structures in the world. It is undoubtedly the outstanding railway site in Australia and one of the finest in the world.
Case 5: The Darjeeling Himalayan Railway, India
The Darjeeling Himalayan Railway is an outstanding line on several counts, but it is particularly significant with regard to social, economic, and political effects and the route’s relationship with the landscape.
Darjeeling, sited at an elevation of over 2000m in the eastern Himalaya, was the first hill station of British India and also the first to be served by rail. The origins of Darjeeling and its railway are part of the expansion of British India during the last decades of East India Company rule. By the early 19th century the Company was the dominant power in northern India and frequently intervened in disputes between Indian princes. Such intervention on behalf of the Raja of Sikkim in 1829 resulted in East India Company officers exploring the then almost uninhabited Darjeeling area. They were impressed, both with its military significance, commanding a pass into Nepal, and with its potential as a cool-climate sanatorium which was not too far from Calcutta, then capital of both the Bengal Presidency and British India as a whole. The Governor-General, Lord William Bentinck, was an enthusiastic westernizer, and so he opened negotiations with the Raja of Sikkim with a view to its acquisition. The Raja ceded the district to the Company in 1833, and in return was granted an annual allowance. Subsequent annexations in the early 1850s made Darjeeling, previously an East India Company enclave in Sikkim, contiguous with the Company’s Bengal Presidency.
Darjeeling grew rapidly under British rule. The population was only about 100 in 1839 but reached 10,000 a decade later. The Hill Cart Road, so named because it was graded so that a bullock cart could climb it, was built from Siliguri on the plains. The cultivation of tea, for which Darjeeling has become famous, began in the early 1840s. At that time, China had close to a monopoly on Europe’s tea supplies, so seeds were brought to Darjeeling to begin the industry. Despite the Hill Cart Road, however, transport remained the district’s great problem. Railway construction on the plains between 1858 and 1878, partly by the broad-gauge Eastern Bengal Railway (EBR) and partly by the metre-gauge state-owned Northern Bengal Railway (NBR), connected Calcutta with Siliguri, at the foot of the Himalaya. This made travel easier for Europeans, who could afford the fares, but did little to encourage further growth in Darjeeling. In the late 1870s, rice, the population’s staple, was sold in Siliguri for 98 rupees per ton, but for 240 rupees in Darjeeling.
Neither the EBR nor the NBR could see how they could extend their lines to Darjeeling, although it was the putative destination of both. Franklin Prestage, the local agent of the EBR, worked out the scheme for the building a narrow-gauge (2ft or 600mm) light railway to Darjeeling. In 1878, the year of the opening of the NBR line to Siliguri, he wrote a persuasive proposal to build the line. There would be a Bengal Government guarantee, which would ensure security for investors, but in return the railway company would be obliged to pay the Government for maintenance of the Hill Cart Road out of its profits. The contract was signed on 8 April 1879 and less than a year later the first train ran from Siliguri to Tindharia. The line was opened in stages, reaching the summit at Ghoom (7402ft/2256m) on 4 April 1881 and the terminus exactly three months later.
The technological inspiration for the line was not any Indian precedent – the 2ft gauge Baroda Railways were worked by bullocks and laid across flat terrain – but the Festiniog Railway in Wales. It had been converted successfully from horse to steam operation in 1868. The big difference was that the Festiniog’s freight traffic was nearly all downhill. The commodity, slate, was also very heavy in relation to its volume, so considerable tonnages could be conveyed in small wagons. The DHR would be carting rice and other supplies up the hill and teas down it. Moreover, there would be a sizeable passenger and mail traffic. The railway did have one big advantage over the Festiniog. This was a far more generous loading gauge, permitting larger locomotives and other rolling stock, but it also had much steeper grades - up to 1 in 20 compared with the Festiniog’s 1 in 50. The average grade over the 64km between Sukna, where the DHR leaves the plains, and the summit at Ghoom is 1 in 30.5.
The DHR does not feature any grand structures. In fact, the whole point of the line’s engineering was precisely to avoid the expense of such features. The remarkable features of the DHR are its steep grades and cheap but effective expedients its engineers adopted to enable it to climb so much in so short a distance. These included, at the time of its opening, four loops, where the line climbed in a circle above itself, and four zigzags. A new loop, the famous Batasia double loop, was built in 1919 to eliminate the 1 in 20 section between Ghoom and Darjeeling, and in 1943 one of the lower loops was replaced by a zigzag, of which there are now five. Curvature is very severe, with the sharpest having a radius of just 59ft (18m). Some of the more alarmingly located sites have been graced with names like Agony Point and Sensation Corner, although the smallest of the Indian hill railways, the Matheran line near Bombay, probably has the most entertainingly named engineering feature – One Kiss Tunnel. For most of its route the DHR follows the Hill Cart Road, which it crosses 132 times.
The DHR was estimated to cost 1,400,000 rupees: Prestage completed it for 1,700,000 rupees which, considering the untried nature of the enterprise, was a good result. It was a profitable line from the start and, until nationalization in 1948, never needed to call on the government guarantee. Revenue and traffic both grew rapidly, along with the Darjeeling district’s economy as a whole. Darjeeling’s cool climate assured a steady stream of mostly European first-class passengers, while the necessity to ship rice into the district and the growth of tea planting meant that there was plenty of freight flowing in both directions. Motor traffic began to eat into the passenger traffic during the 1920s, but freight traffic and then wartime demands kept the railway’s finances buoyant. However, the railway has never really recovered from the effects of Partition in 1947, which led to its railway connections with the rest of India being severed for a period. Even as traffic to Darjeeling revived, most of it began to go by road, as trucks and buses improved. For the DHR, for all its charms, was and remains a slow railway. Today freight traffic has been lost and passenger figures are down to around 100,000 per annum (Sarkar 1980: 8-10, 14-7; Bandhari 1984: 1-36).
Despite its small size, this is a very significant railway in any terms. It has helped make Darjeeling synonymous with quality tea, by breaking the transport bottleneck which inhibited the district’s growth in the late 19th century. It was the first hill railway of its type, and so was the precedent for the later Nilgiri, Simla, and Matheran lines in India, as well as for railways such as the Dalat line in Vietnam and the Maymyo line in Burma. It demonstrated, even more startlingly than the conversion of the Festiniog to steam operation had done, what could be done with a very narrow-gauge railway in terms of the traffic that could be conveyed, the economy of construction, and the terrain that could be overcome.
From its inception, the DHR was widely recognized as a remarkable railway. In heritage terms, the railway is well preserved, and the changes have not damaged its value. The station at Darjeeling is a mid 20th century Art Déco folly, but most of the larger intermediate stations remain much as they were at the line’s opening. The locomotives working the line to this day are all to a design thought out by Prestage. Thirty-two of these class B 0-4-0 saddle tank locomotives were delivered between 1887 and 1927, and about twenty are still working on the line. This continuity in motive power adds to the railway’s heritage value.
Despite its small scale, the engineering, social, political, and economic impact of the DHR are significant enough to justify its place on any list of important railways. However, what really makes the DHR outstanding is its relationship to the landscape through which it passes. The railway begins on the plains of West Bengal and soon begins climbing through a remnant of lowland jungle, including stands of teak. As the railway climbs, so the flora changes, and its upper sections are dominated by enormous Himalayan pines, which in misty weather give a surreal quality to the landscape. It frequently hugs the edge of hillsides with drops, often of thousands of feet, to the plains and valleys below. Towering over the entire scene is the perennially snow-covered bulk of Kanchenjunga, at 28,146ft (8579m) the third highest mountain in the world. From Kurseong (31 miles or 49km from Siliguri at an elevation of 4846ft or 1524m) the railway offers frequent views of this stupendous mountain, which by Ghoom dominates the entire landscape. Thus, from the tiny train, the passenger can look down on the stifling tropical plains of Bengal or up into the eternal snows of the highest peaks of the Himalaya. No railway anywhere else offers such a sight.
Case 6: The Liverpool & Manchester Railway, United Kingdom
The world’s first main line constructed for both passenger and freight business, dating from 1830, is an excellent example of a railway where much of the route is still in use. The two original termini, at Liverpool Road, Manchester, and Edge Hill, Liverpool, were soon superseded (although both still survive in part), but the rest of the railway is still heavily used, demonstrating its sound economic and technical basis.
The Liverpool & Manchester’s role as the international prototype for the Stephensonian mechanically worked railway – engineered to a high but, for European nations, not impossibly expensive standard – makes it an excellent illustration of the criterion of technology transfer. Earlier mechanically worked railways had tended to be of the ‘hybrid’ variety, utilizing both fixed and locomotive haulage; the Liverpool & Manchester was, with the exception of one short, steep stretch at the Liverpool end, the first to be built and completed solely for locomotive operation (Donaghy 1972). It therefore constituted a new kind of railway – the main line, built to link large centres of population and carry goods and passengers in both directions, a precedent which then spread world-wide. The famous Rainhill locomotive trials of October 1829 took place on a section of the Liverpool & Manchester to determine the type of engine which would be adopted. The winner, Robert Stephenson’s Rocket, set a course for nearly 150 years of steam locomotive development. The massive contribution to the Liverpool & Manchester of Robert Stephenson and his father George, the railway’s chief engineer, suggests that particular sites may indeed be seen as works illustrative of creative genius even though in this, as in so many other cases, modern scholarship reveals that success was dependent upon the contributions of a great number of individuals (Smith 1994; Rolt 1960) .
The Liverpool & Manchester is also illustrative of the intimate relationship between railway development and social and economic factors. The promotion of the line was a direct consequence of attempts to break the virtual monopoly held by the proprietors of the Bridgewater Canal on transport between two of England’s most rapidly industrializing cities. Once built, the railway itself contributed to the rapid quickening of the pace of industrialization in north-west England. These effects were partly the result of the railway’s high technical standards: it provided quick, reliable and comparatively cheap transport along its direct, gently curved, and easily graded route. Such engineering required large and extensive earthworks and other, often innovative, technical features. The deep cutting through rock at Olive Mount, Liverpool, and the method used by George Stephenson to cross Chat Moss, a notorious area of bog, are particular features of note. So too, for rather different reasons, is the memorial to the Member of Parliament, William Huskisson, run down on the railway’s opening day by Rocket. The improved lines of communications across the country heralded by the Liverpool & Manchester played an important, if imperfectly understood, part in the political and social evolution of Britain throughout the 19th century (Simmons 1986).
The Liverpool & Manchester also demonstrates the kind of conflicts that inevitably occur on a working railway between historical authenticity and originality on the one hand and renewals on the other. Yet this very continuity of operation demonstrates that the railway has remained true to something like its original purpose for nearly 170 years. Many original features survive apart from the route itself. Liverpool Road station is now part of the Museum of Science and Industry in Manchester, and as an early goods handling complex is very complete. As well as the original passenger station, the site incorporates a brick curved viaduct past the 1830 warehouse, quite an engineering feat at the time although it is hidden by the buildings on both sides (Fitzgerald 1980). At the other end of the line, Edge Hill passenger station is listed nationally as being of historic importance, and Chatsworth Street cutting, where the stationary haulage engines gave way to locomotives, has been excavated and is partially in use as a head-shunt for a marshalling yard. The fact that many of the original features on the rest of the railway remain in use says much about the quality of the engineering that went into their construction. Several original skew bridges (a technology transferred from canals) survive, features that the original company took great pride in. At Sankey Brook is the first railway viaduct in the world of any length; this now carries much longer and heavier trains than it was ever designed to carry. The viaduct is also of note in that it carries the railway over the first commercial canal in Britain. At St Helens is the site of the first bridging of one railway over another, where the St Helens & Runcorn Gap Railway passed over the Liverpool & Manchester.
As the railway which set the precedent for what was to come, the Liverpool & Manchester Railway is a remarkable survival of a transport corridor that demonstrates the relevance of many of the proposed criteria for World Heritage status.
Case 7: The Great Western Railway, United Kingdom
It has been remarked that the Great Western Railway was built by gentlemen for gentlemen. The original main line, constructed from 1838 to 1841, runs from Paddington in west London (though the present splendid station dates only from 1854) to Bristol Temple Meads (where much of the original survives, adapted for reuse). In conception and execution the railway was a grand affair, although as with most lines in Britain considerations of commerce and profit were always as much, if not more, in the minds of the original promoters than those of civic and class identity (Gren 1998). It is still the principal route to the west of England, carrying fast expresses now as it was always intended to do.
Above all the GWR is as an excellent demonstration of how the criterion of works illustrative of genius may be applied in many ways. The railway was dominated, more than any other in Britain, by the vision of just one man, Isambard Kingdom Brunel. This very dominance serves to illustrate the need to be sensitive to the many different kinds of skills and resources needed to build a railway. Brunel came to pre-eminence partly because of the particular pattern of financing the line, which meant that shareholders were divided amongst themselves and unable to exercise the usual measure of control over their employee (Gren 1998). However, whatever the reason, the Great Western was shaped by Brunel’s arguably flawed genius for strategic thinking (Vaughan 1991). Along the route are constant reminders that this railway was once built to the broad gauge of 7ft (2135mm), while many surviving structures bear the mark of his innovative civil engineering. Significant Brunellian features include the Wharncliffe Viaduct, the Sonning Cutting, and the bridge over the Thames at Maidenhead with its two long, flat arches, a triumph of civil engineering which cynics said would collapse when the scaffolding was removed. The 2 mile long Box Tunnel in Wiltshire, with its ornate portals, and a handful of surviving stations show the engineer’s wide-ranging influence in their architectural styling (Pugsley 1976). Brunel’s hold over the GWR was almost total, gaining the railway a reputation at the time of being ‘The Finest Work in England’ (Rolt 1960: 141).
Economic considerations were very much part of the planning of the GWR. These, too, were developed in the grand style. Brunel intended that the railway would not only join London and Bristol but would also form part of a link between London and New York, employing iron steamships from Bristol. Transatlantic trade would be encouraged by the new link. This was socio-technical system building of the highest order, and Brunel’s vision goes part way to explain the willingness of the GWR’s backers to put forward the very large financial sums needed for the line’s construction: their livelihoods would benefit from the new railway. The social relevance of railways is also borne out by the GWR. The route passes through the early railway town of Swindon, a settlement that owed its very existence to Brunel’s decision to site the railway’s principal workshops there. The town still bears many signs of its origins, although the workshops are no longer in use and have been partially cleared (Cattell & Falconer 1995).
As with the Liverpool & Manchester and other operating railways, the Great Western is likely in the future to produce many dilemmas as modern requirements come to be reconciled with the desire to ensure the survival of original features. These challenges are made less pressing than usual by the very fact that Brunel constructed an extremely well (perhaps over-) engineered railway with such a thorough attention to detail that much of it remains suitable for high-speed use today. As a complete and still operating entity, ‘Brunel's Billiard Table’ with gentle curves and lack of sharp gradients is a fine tribute to the man who designed and the men who built it.
Case 8: The Shinkansen, Japan
The Japanese Shinkansen has been to modern high-speed railways what the Liverpool & Manchester line was to rail travel in the 1830s in terms of technical innovation.
After World War II, the population and industrial expansion which took place on the coastal belt of Japan between Tokyo and Osaka forced the Japanese National Railways (JNR) to find ways to expand its carrying capacity. It appeared futile to try to find extra capacity on the already overstretched 3ft6in (1067mm) gauge Tokaido main line. In any case, operations were severely hampered by frequent level crossings – as many as a thousand – and the route was lined by buildings, preventing the construction of additional lines of track. Since it was passenger traffic which was expanding at the greatest rate, it was decided to build an entirely new standard-gauge railway from Tokyo to Osaka which would serve only the most important intermediate settlements. The choice of the standard gauge also meant that a higher speed would be possible. The narrow-gauge line could then concentrate on handling goods and local passenger traffic.
The new railway was to be something quite unprecedented world-wide. Having only one purpose, it could be engineered solely for one type of train, a train where speed and comfort were of the essence. The power was electricity, and from the start a very frequent service was run throughout the day. Trains were of a standard type, running at very high speeds on a double-track line, all supervised from a central control centre in Tokyo. Through the use of modern technology to communicate with the trains, this New Tokaido line was able to dispense with track-side signalling, the first ever main line to do so. The route was entirely new, although roughly parallel to the original narrow-gauge line for much of the distance. Connecting only the principal towns, the total number of stations on the line is twelve, including the two termini.
One could argue that the Shinkansen illustrates the continued relevance in the 20th century of the criterion of genius, a genius which changed the concept of travel by train into a new efficient system which continues to spread its influence throughout the world in the quest for speed and efficiency, drawing boundaries ever closer. The head of the Shinkansen design team was Hideo Shima, who worked on the track and trains to create something completely different. The line was built on a raised concrete base with the express intention of avoiding steep gradients and curves: this was a breakthrough in passenger train technology similar to the conversion of the airline industry to jet propulsion. From Osaka to Tokyo, the route has 3000 bridges and 67 tunnels to make it as level as possible, the result being that on average trains arrive within 40 seconds of their scheduled time. The individual cars of the train have their own electric motors, and each train set is air-conditioned and employs air suspension. Safety standards are exemplary. Seismometers installed along the track automatically trigger equipment to halt the trains if any tremors occur in this area of tectonic activity; since opening, no passenger has ever been killed in an accident. Hideo Shima also designed the aerodynamic front of the train, which gave rise to the name ‘Bullet Train.’ Eventually he was given the Japanese Order of Cultural Merit for his work, and he was also the first non-Westerner to receive the prestigious James Watt award for mechanical engineering.
The Shinkansen also illustrates the applicability of the criterion of significant social and economic effects to railways of the 20th century. The line was opened for limited traffic in 1964, and began full operations in 1966. It was an immediate success, both financially and operationally. Despite high construction and operating costs, the new line was able to deliver a healthy surplus of revenue over and above the capital charges and running costs, even though social and economic considerations on the part of the Japanese government kept fares at a comparatively low level. Further lines and extensions on essentially the same model were planned and built as a result: speed was what passengers customers wanted, and they were willing to pay a premium over the usual fare to get it. Politicians pushed to have lines built to their areas as a symbol of economic prowess, while the trains were also agents of social change in that young people in the countryside were able to have quick access to urban areas.
The Shinkansen exemplifies the criterion of international technology transfer in the modern period. Engineers in Europe watched the success of the Japanese high-speed line with envy, but it was to be a decade before anything like it would be emulated outside Japan. Now, thirty years on, it is possible to see the fundamental concept of the Shinkansen in the new high-speed trains such as the French TGV, the German ICE, and Franco-British-Belgian Eurostar which run on purpose-built railways across Europe. On a national scale the original Shinkansen had symbolized Japan’s final movement out of the shadows of war-time defeat and industrial dependency. Now in the late 20th century the line stands additionally as a symbol of international leadership in the technology of high-speed land transport (Whitelegg et al 1993).
Railways are among the most important of industrial locations worthy of designation as World Heritage Sites. The designation of a carefully selected number of outstanding sites would bring to greater prominence the many ways in which railways have contributed – and in many cases continue to contribute – to the social, economic, political, cultural, and technical evolution of almost every country around the globe.
This survey does not pretend to identify those railway locations that are worthy of designation. It seeks only to provide a little of the general background that is needed to appreciate the true historical significance of railways, and to demonstrate the applicability of the usual criteria for World Heritage Sites to the particular case of railways.
Not all railways worthy of World Heritage status need be designated in their own right. Railways have always been built as a means to some other end, and it would be fitting if this fact were reflected by the inclusion of railways as integral parts of locations designated as World Heritage sites partly or chiefly for other reasons. This has, of course, already happened in one or two instances: for example, the routes of several early railways fall within the Ironbridge Gorge World Heritage Site. Again, complexes of important warehouses and other goods facilities at points along a route might be included within other kinds of designated sites, where appropriate, in order to demonstrate the railways’ interaction with industry and other modes of transport.
Nevertheless, railways enjoy a distinctive enough identity as a kind of socio-technical system for them to be worthy of designation in their own right. Their long history has produced a rich heritage fully the equal of any other aspect of modern society. Continued usage is surely the most fitting recognition that the present generation can accord the achievements of the railways’ past. Yet the continued relevance of railways to contemporary society in many parts of the world means that certain aspects of their heritage is at risk from unsympathetic modernization and renewal. The designation of outstanding railway locations as World Heritage Sites can help to ensure a future whereby the achievements of the past are recognised and appreciated as an integral part of the continuing evolution of railways into the next century.
This survey would not have been possible without the generous financial assistance of ICOMOS from funds provided by the Austrian Government, and of the UK’s National Museum of Science and Industry (National Railway Museum). It was compiled with the assistance of Professor Colin Divall of the Institute of Railway Studies, York. The considerable input of some 70 experts, both in person and through correspondence, is also gratefully acknowledged. Special thanks are due to Dr Robert Lee of the University of Western Sydney, MacArthur, New South Wales, Australia (who contributed the studies on the Darjeeling Himalayan Railway and the Great Zig-Zag); Mme Marie-Nöelle Polino of AHICF, Paris; Herr Günter Dinhobl of the Austrian Alliance for Nature; and the guiding hand of Professor Henry Cleere, World Heritage Coordinator, ICOMOS, Paris. The help and encouragement of colleagues in the Institute of Railway Studies and the National Railway Museum is also warmly appreciated.
Much of the study is based on the proceedings of the World Railway Heritage Conference, held at the National Railway Museum, York, on 16 March 1998, and on subsequent discussions. The photographs used are from the collections of the National Railway Museum and individual correspondents.
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Appendix - Members of the Advisory Committee and Correspondents
Professor Henry Cleere, World Heritage Co-ordinator, ICOMOS, Paris, France, and
Institute of Archaeology, University College London, UK.
Sir Neil Cossons, Director, National Museum of Science and Industry, London, UK
Professor Colin Divall, Head, Institute of Railway Studies, York, UK
Stephen Hughes, Royal Commission of Ancient and Historical Monuments in Wales,
Dr Robert Lee, University of Western Sydney, MacArthur, New South Wales, Australia
Ashwani Lohani, Director, National Rail Museum, India
Marie-Noëlle Polino, AHICF, Paris, France
Andrew Scott, Head, National Railway Museum, York, UK
Dr Michael Stratton, University of York, UK
Dr Barrie Trinder, Nene College, Northampton, UK
Participants in the International Conference, York, 16 March 1998
In addition to members of the Advisory Committee:
Michael Bailey, Institute of Railway Studies, York, UK
Gordon Biddle, independent scholar, UK
Winstan Bond, National Tramway Museum, Crich, UK
Tadej Brate, Ministry of Culture, Slovenia
Phillip Butterworth, University of New South Wales, Australia
Mike Clarke, Milepost Research, Accrington, UK
Jim Cornell, Railway Heritage Trust, UK
Anthony Coulls, Institute of Railway Studies, York, UK (Conference co-ordinator)
Günter Dinhobl, Alliance for Nature, Austria
Clive Ellam, Vice-President, Newcomen Society, UK
Helen Gomersall, West Yorkshire Archaeological Service, Wakefield, UK
Victoria Haworth, Robert Stephenson Trust, Newcastle, UK
Dr Tony Heywood, Bradford University, UK
Dieter Hopkin, National Railway Museum, York, UK
Sinikka Joutsalmi, Department of Antiquities, Finland
J Mitchell & J Fleming, Heritage Engineering, Glasgow, UK
Jill Murdoch, Institute of Railway Studies, York, UK
Peter Northover, University of Oxford
David Percival, Royal Commission on Ancient and Historic Monuments in Wales,
Martin Robertson, English Heritage consultant, Bath, UK
Bob Scarlett, independent scholar, Sunderland, UK
Christian Schuhböck, Alliance for Nature, Austria
Peter Semmens, independent scholar, York, UK
Denis Smith, President, Newcomen Society, UK
D P Tripathi, Indian State Railways, India
Audrey Trotti, University of York, UK
Jacek Wesołowski, Politechnika Łodz, Poland
John Wilcock, Staffordshire University, UK
John Wonnacott, Institute of Railway Studies, York, UK
Lars Olov Karlsson, Curator, Banmuseet, Sweden
Jurgen Franzke, Director, DB Museum, Nuremberg, Germany
Tatsuhiko Suga, Executive Director, East Japan Railway Culture Foundation, Japan
Dr Anthony Streeten, English Heritage, London, UK
David Mitchell, Hertfordshire, UK
Dr Paul Waters, British Overseas Railway Historical Trust, Surrey, UK
Rabbi Walter Rothschild, Berlin, Germany
Ian Thomson, Chile
Professor Senake Bandaranayake, Sri Lanka
Professor V V Alexeyev, Ekaterinburg, Russia
Dr Eugene Rukosuyev, Institute of History and Archaeology, Ekaterinburg, Russia
C Weevers, Rijksdienst voor de Monumentenzorg, The Netherlands
Professor Georges Calteux, Luxembourg
Andris Biedrins, Latvia
Christopher Andreae, Historica Research Ltd, Canada
Guido Vanderhulst, La Fonderie, Belgium
Professor Jorge O Gazaneo, Argentina
Dr M J T Lewis, University of Hull, UK
Thomas Kappel, Denmark
Hossam Mahdy, Architectural Conservation Consultant, Egypt
Charles Alban, USA
Greg Hallam, Historical Researcher, Australia
Bela Banerjee, Ministry of Railways, India
B Z Manyangadze, Mutare Museum, Zimbabwe
Nick Sbarounis, Association of the Friends of the Railway, Greece
Omar Gil Soja, FADARTE, Uruguay
Billiard Lishiko, Curator, South West Region Railway Museum, Zimbabwe
Angel Ferrer, Rosario, Argentina
Jorge Waddell, Fundación Museo Ferroviario, Argentina
Kodituwakku A Kusumsiri, Research Officer, Sigiriya Project, Sri Lanka
Lou Rae, Tasmania
Robert C Post, President, Society for the History of Technology, USA
Andreas Dreier, Director, Norwegian Railway Museum, Norway
William L Withuhn, Curator of Transportation, Smithsonian Institution, USA
Our apologies to anyone who has been accidentally omitted.
Les Théâtres et les Amphithéâtres antiques
|Par Jean-Charles Moretti, 1999
IRAA du CNRS, Lyon, France
I. L'histoire du théâtre antique
Les édifices à gradins de la Crète minoenne mis à part, l'architecture théâtrale semble apparaître en Grèce dans le courant du VIe. s. av. J.- C., à l'époque où sont institués le programme des grands concours religieux et les règles de leurs épreuves. Dans le même temps furent sans doute créés trois types monumentaux pour recevoir les trois types d'épreuves distinguées par les Grecs. Les épreuves hippiques prenaient place dans l'hippodrome, les épreuves gymniques dans le stade et les épreuves dites « musicales », car elles avaient partie liée avec les Muses, dans le théâtre. Les édifices de spectacle du VIe s. accueillaient les spectateurs sur des gradins de bois, montés sur des échafaudages. Ils sont connus par des textes et par des représentations sur des vases. Les plus anciens vestiges de théâtres retrouvés remontent au Ve s. et se répartissent dans la péninsule hellénique entre la Béotie et le Nord-Est du Péloponnèse en passant par l'Attique. Tous les théâtres de Grèce ont en commun certaines caractéristiques. Leurs koilons sont adossés à des éminences naturelles, taillées ou aménagées pour l'occasion et si nécessaire complétées par des remblais que peuvent contenir des murs de soutènement. Les gradins de pierre, quand ils existent, prennent la forme de simples degrés, avec une face antérieure et un lit supérieur plans. Dans plusieurs édifices, seul le premier rang est occupé par des trônes derrière lesquels un terrain déclive accueillait les spectateurs assis par terre ou sur des bancs de bois. La partie centrale du koilon est toujours composée de gradins rectilignes. Parfois, elle est complétée par deux ailes de gradins qui, vers leurs extrémités antérieures, divergent par rapport à l'axe du monument. Aucun koilon n'est divisé par des circulations horizontales. L'orchestra est de forme allongée, trapézoïdale ou rectangulaire. Elle est accessible latéralement par de larges parodos, qui jamais ne sont obturées par des portes. Nulle part n'a été retrouvé de mur d'un éventuel bâtiment de scène, mais les textes dramatiques conservés ne laissent pas douter qu'il en existait au moins en Attique, construits avec des matériaux périssables. Parmi les édifices qui remontent au Ve s. le mieux conservé est celui de Thorikos (Attique, Grèce), mais le plus important au regard de l'histoire architecturale et littéraire est celui du sanctuaire de Dionysos Éleuthéreus à Athènes.
Une série de gradins rectilignes, taillés dans le rocher, a été trouvée à Syracuse et datée du Ve s. par comparaison avec les dispositifs de Grèce, bien que l'on manque d'arguments pour justifier une datation si haute. À l'époque classique les différents types de spectacles montés dans les théâtres de Grèce étaient connus en Sicile et la Grande Grèce, mais il n'existait pas en Occident de grands concours de musique, de danse et de drame. En l'absence de vestiges d'édifices qui aient pu recevoir ces divers spectacles, on suppose que les représentations étaient données dans des constructions éphémères, comparables à celles représentées sur les vases dits « phlyaques », produits en Italie du sud entre le début et le troisième quart du IVe s. av. J.-C. Ceux-ci portent en effet la représentation de scènes de comédies attiques dans lesquelles les acteurs jouent sur des estrades de bois temporaires. Le recours à un tel équipement invite à croire qu'il n'était pas à cette époque d'édifice en pierre apte à recevoir les représentations.
Il s'en construisit plusieurs à partir de la seconde moitié du IVe s. et tout au long de l'époque hellénistique en Italie méridionale, à Locres et à Métaponte, mais plus encore en Sicile, à Akrai, Héracléa Minoa, Iaitas, Morgantina, Ségeste, Solonte, Syracuse ou Tyndaris, pour ne citer que les théâtres dont les vestiges sont les mieux conservés. Avec leurs koilons à gradins arqués et leurs bâtiments de scène à estrade haute, ils ne sont pas sans rappeler leurs contemporains de Grèce. Dans le détail, cependant, les différences ne sont pas négligeables. Les koilons sont en demi-cercle, mais rarement outrepassés. Le plus souvent les murs de soutènement antérieurs sont parallèles au front du bâtiment de scène. Les orchestras semi-circulaires ont des surfaces relativement réduites. Les parodos sont étroites, car les bâtiments de scène sont généralement proches deskoilons. Les proskènions sont de hauteurs comparables à ceux de Grèce, mais leurs fronts sont parfois murés et décorés d'atlantes ou de caryatides. Leur profondeur est dans plusieurs édifices relativement importante, atteignant 4,50 m et dépassant parfois les 6 m. Le front de l'étage desskènès donnant sur la couverture du proskènion est percé non pas de larges baies, mais de trois portes que les artistes atteignent par des escaliers situés à l'intérieur de la skènè. Dans plusieurs édifices, il est orné de colonnes doriques engagées et surmonté d'une sorte d'attique aveugle, lui aussi orné de pilastres ou de demi-colonnes. De part et d'autre du proskènion, la skènè présente dans plusieurs monuments des avant-corps à étages.
De telles différences morphologiques avec les théâtres de Grèce induisent un type d'utilisation des édifices scéniques en Italie du sud et en Sicile distinct de celui reconnu dans la péninsule hellénique et dans les Cyclades. En Occident, les acteurs jouaient habituellement sur le proskènion et non dans l'orchestra. Les modèles monumentaux mis au point en Grèce au début de l'époque hellénistique ont probablement eu une influence sur l'architecture théâtrale occidentale, mais ils n'ont pas été simplement exportés dans ces régions. Ils le furent en revanche en Orient ou, du moins, dans les grandes cités de la côte occidentale de l'Asie mineure, où furent construits, à partir de la fin du IVe s. av. J.-C., des édifices étroitement apparentés à ceux de Grèce.
Au début du Ier s. av. J.-C. apparaissent en Italie (Tusculum, Pompéi) des bâtiments de scène à estrade profonde (pulpitum) bordée par un front de scène percé de trois portes et orné de colonnes qui se dressent sur des podiums et sont détachées du mur de fond. Ces caractéristiques sont présentes dans le théâtre de type « romain » dont la gestation trouve son terme à Rome avec le théâtre de Pompée, en 55 av. J.-C., et celui de Marcellus, inauguré dans les années 20 av. J.-C. Le théâtre devient alors un édifice unitaire et indépendant du relief naturel. La conque semi-circulaire des gradins est portée par des murs rayonnants surmontés de voûtes, dont la maîtrise de l'opus caementicium facilite la réalisation. Dans cette structure creuse sont ménagés des passages couverts qui desservent les différentes zones de la cavea. Les gradins et parfois des tribunes réservées aux organisateurs des spectacles couvrent les parodos. La cavea est conjointe au bâtiment de scène, la longueur de celui-ci s'assimilant au diamètre de celle-là. Dans certains édifices un portique couronne les gradins. Peu développée, l'orchestra est pavée et reçoit les fauteuils mobiles des dignitaires. Tout le spectacle se déroule dorénavant sur la profonde estrade du bâtiment de scène. Un rideau, qui s'abaisse au début des spectacles, peut momentanément la cacher aux yeux des spectateurs. Derrière lui se dresse le front de scène, un mur dont le sommet règne avec celui de la cavea et qui, à ses extrémités, fait retour vers l'orchestra, définissant ainsi les flancs de l'estrade. Il est orné de placages de marbre, de statues contenues dans des niches et d'un ou de plusieurs niveaux superposés de colonnes dégagées. Derrière le mur de scène se trouvent généralement des vestiaires et des foyers. Les théâtres les mieux conservés du monde romain, ceux d'Orange (France), d'Aspendos (Turquie) et de Bosra (Syrie), portent la trace d'auvents qui couvraient le front de scène et l'estrade. Dans plusieurs monuments les gradins étaient ombragés par les vela, pièces de tissus montées sur des cordes, elles-mêmes fixées à des mâts.
D'une région à l'autre de l'Empire et à l'intérieur d'une même province, des théâtres de formes sensiblement différentes ont coexisté. La plupart des villes qui possédaient des édifices antérieurs au Ier s. av. J.-C. les ont conservés ou en ont seulement modifié le bâtiment de scène. En Asie mineure, où les traditions hellénistiques étaient fortement enracinées, le koilon adossé en demi-cercle outrepassé et le bâtiment de scène à estrade d'une hauteur équivalente à celle d'un proskènion restent fréquents. Le front de scène y est généralement percé de cinq portes alors qu'il n'en comporte que trois en Occident. Il est orné de colonnes implantées parallèlement à un mur de scène rectiligne, tandis que dans le reste de l'Empire des dispositions plus variées avec une ou plusieurs incurvations du mur et de la colonnade sont adoptées dès le Ier s. Dans les provinces d'Aquitaine, de Lyonnaise et de Belgique, le théâtre dit de type gallo-romain associe une cavea adossée, outrepassant souvent en demi-cercle et parfois garnie de gradins de bois, à un bâtiment de scène qui se réduit à une profonde estrade installée dans l'orchestra et à un mur de scène masquant la coulisse.
Apparu pour servir de cadre à des concours et plus généralement à des spectacles musicaux, orchestiques et dramatiques, le théâtre a aussi servi, au cours de son histoire, à d'autres réunions, dont certaines ont nécessité des transformations du bâtiment. Dans les cités de l'Orient grec il a reçu des assemblées politiques. Il a aussi servi, à l'époque impériale, pour des chasses et des combats de gladiateurs aussi bien en Gaule qu'en Orient ou en Afrique. Les gradins ont alors été séparés de l'orchestra par de fortes dénivellations, par des murets ou par des grilles et des filets, tandis que des refuges étaient aménagés pour les chasseurs. Quelques théâtres ont même été conçus dès leur construction pour les spectacles de l'arène. Certaines orchestras ont été transformées en bassins pour recevoir des mimes aquatiques, qui semblent avoir été prisés au IVe s.
II. L'histoire de l'amphithéâtre antique
L'amphithéâtre, comme son nom l'indique, se présente comme la combinaison de deux théâtres. Il comprend une arène autour de laquelle se développent des volées de gradins. Les édifices de Capoue et de Pouzzoles (Italie), construits à la fin du IIe s. av. J.-C., constituent les plus anciens exemplaires de ce monument, qui avait pour destination première d'accueillir des combats de gladiateurs. L'habitude d'organiser de tels spectacles n'était pas alors une nouveauté : dès le IIIe s. des combats sont attestés lors de funérailles en Étrurie et en Campanie. À Rome même, il s'en disputa pour la première fois en 264 av. J.-C., au forum Boarium, puis à maintes reprises sur le forum lui-même. La place, sous laquelle avaient été creusées des galeries de service, servait d'arène. Des gradins de bois érigés à l'entour recevaient les spectateurs. Apparu tardivement, l'amphithéâtre ne s'imposa pas comme le seul cadre des chasses et des combats de gladiateurs. Le premier amphithéâtre à Rome, construit en 29 av. J.-C., fut longtemps concurrencé par le Forum puis par le Champ de Mars.
À partir du Ier s. av. J.-C., cependant, les amphithéâtres se multiplient. L'arène revêt généralement un plan elliptique, qui est le plus favorable à la perception des spectacles par l'ensemble du public. Elle est accessible par des portes situées aux extrémités du grand axe de l'ellipse et complétées dans certains édifices par des accès sur son petit axe. Sous son sol sont aménagés à partir de l'époque augustéenne des chambres et des couloirs dont certains sont reliés à la surface par des trappes. Des monte- charges hissaient les bêtes destinées aux chasses. Une haute dénivellation couronnée d'un parapet sépare l'arène du public. Comme dans le théâtre, les gradins sont divisés horizontalement par des précinctiones définissant des maeniana et verticalement par des escaliers rayonnants limitant des cunei. Dans les édifices les plus anciens, l'arène était parfois creusée et la cavea était adossée au terrain naturel ou reposait sur du remblai qui, compartimenté ou non, était retenu par un mur à sa périphérie. Les accès aux gradins étaient alors disposés à l'extérieur du monument. Ce mode de construction resta majoritaire jusque dans les années 60 ap. J.-C., mais fut concurrencé à partir de la seconde moitié du Ier s. av. J.-C. par le dispositif à structure creuse adopté dans les théâtres. Des murs rayonnants reliés par des voûtes supportaient les gradins. Des galeries périphériques et des escaliers intégrés à la substructure de la caveaconduisaient à des vomitoires. La façade externe du monument se présentait comme une superposition de un à trois niveaux d'arcades et d'un attique décoré d'ordres engagés.
L'exemplaire le plus grand et le plus élaboré de ces édifices à substructions artificielles fut l'Amphithéâtre flavien de Rome, communément appelé Colisée. Commencé en 71 ou en 72 à l'initiative de Vespasien, il fut inauguré sous Titus par cent jours de spectacles durant lesquels cinq mille bêtes sauvages furent tuées. Le chantier fut achevé sous Domitien après plus de douze années de travaux. Son arène de 79,35 x 47,20 m était comprise dans une cavea de 187,75 x 155,60 m. Quelque cinquante-six rangées de gradins, divisées à l'image des groupes sociaux qui y siégeaient, pouvaient recevoir environ 60 000 personnes. Les premiers degrés recevaient les sièges mobiles des spectateurs de marque. Les derniers, construits en bois, étaient disposés sous un portique. La façade extérieure en travertin se composait de trois niveaux de quatre-vingts travées superposant les ordres dorico-toscan, ionique et corinthien. Un attique à pilastres corinthiens couronnait la construction. Percé de fenêtres et orné de boucliers, il portait les consoles utiles à la fixation des mâts du velum ombrageant les gradins. Un détachement de marins de la flotte était affecté au maniement des cordages de cette immense voilure. Dans son dernier état, le sous-sol de l'arène était entièrement aménagé et relié par un corridor souterrain à la grande caserne de gladiateurs située à proximité de l'amphithéâtre. L'édifice servit de modèle à de nombreux amphithéâtres construits dans l'Empire, sans néanmoins y imposer une uniformité planimétrique. En Gaule, il fut concurrencé par des monuments combinant une arène à une cavea incomplète.
En Occident, l'amphithéâtre fut de la fin du Ier s. au milieu du IIIe s. le signe le plus évident de la romanité et de l'urbanité. En Orient, en revanche, l'amphithéâtre connut une faible diffusion. Dans les pays où la culture grecque était bien implantée, peu d'amphithéâtres furent construits. Les théâtres et les stades furent souvent aménagés pour recevoir les spectacles de l'arène.
III. Critères proposés pour le classement des théâtres et des amphithéâtres
Les édifices devront répondre à plusieurs des sept critères ci-dessous énoncés. Les quatre premiers s'appliquent à la représentativité des monuments et les trois autres à leurs avantages documentaires :
|1||être un représentant insigne de l'un des différents types de théâtres ou d'amphithéâtres qui ont existé dans l'Antiquité|
- théâtre grec classique avec koilon à gradins rectilignes (type Thorikos), sans bâtiment de scène construit en pierre
- théâtre oriental hellénistique avec bâtiment de scène à proskènion et front de scène à baies et avec koilon à gradins en demi-cercles outrepassés (type Épidaure, Oropos ou Priène)
- théâtre occidental hellénistique avec bâtiment de scène à proskènion et front de scène à portes orné d'ordres engagés superposés et avec koilon semi- circulaire (type Ségeste ou Tyndaris)
- théâtre impérial de type micrasiatique avec front de scène à cinq portes et koilon en demi-cercle outrepassé (type Hiérapolis, Pergé ou Sidé)
- théâtre impérial avec front de scène à trois portes et cavea en demi-cercle soudé au bâtiment de scène. Dans cette catégorie, on distinguera les caveae adossées des caveae construites sur structures creuses et les différents fronts de scènes selon qu'ils sont rectilignes (type Philippopolis ou Aspendos), pourvus d'une niche médiane arquée et de deux niches latérales rectangulaires (type Orange ou Mérida), d'une niche médiane rectangulaire et de deux niches latérales arquées (type Bénévent ou Taormine) ou de trois niches arquées (type Lepcis Magna, Sabratha ou Bosra).
- théâtre gallo-romain (type Sanxay, Saint Marcel ou Drevant).
- théâtre avec front de scène et arène prévue dès la conception pour recevoir des chasses et des combats de gladiateurs (type Stobi ou Héraclée de Lyncestide).
Pour les amphithéâtres, on distinguera les édifices complets selon leur plan (oblong, circulaire ou elliptique) et selon leur structure (pleine ou creuse). Les édifices à arène (type Grand, France), où les gradins n'entourent pas l'aire sur toute sa périphérie, ne seront pas négligés.
2 avoir été un modèle architectural
L'évolution de la forme du théâtre et de l'amphithéâtre antique n'a pas été sans ruptures. Certains édifices ont marqué des étapes importantes dans la création des différents types et ont servi de modèles pour la réalisation d'autres monuments : ce fut le cas, à Rome, du théâtre de Pompée, de celui de Marcellus et du Colisée. D'autres édifices, sans avoir peut-être eu une grande importance dans l'histoire de l'évolution des types, demeurent pour nous les rares vestiges qui en illustrent la gestation : c'est le cas, par exemple, des théâtres de Thorikos (Grèce), de Tusculum, de Pompéi (Italie), d'Aphrodisias de Carie (Turquie) ou de l'amphithéâtre de Saintes (France), qui illustre la transition entre les structures pleines et les structures creuses.
3 avoir conservé les vestiges de nombreuses transformations
Certains théâtres ont été utilisés durant près d'un millénaire. Au cours de leur existence ils ont été transformés pour répondre à l'évolution des exigences des spectateurs et à celle des spectacles, recevant successivement les ressortissants de cités indépendantes puis les sujets d'un empire et des oeuvres musicales composées pour des concours puis des chasses ou des combats de gladiateurs donnés en l'honneur de l'empereur. Les vestiges de leurs différents états illustrent l'histoire des sociétés, des formes architecturales et des spectacles. Certains édifices, et en particulier plusieurs amphithéâtres, ont été largement transformés entre la fin de l'Antiquité et l'époque contemporaine. Ces transformations, trop souvent occultées par des restaurations modernes, devront être prises en compte pour évaluer la richesse de l'histoire architecturale des monuments.
4 avoir conservé des vestiges de son environnement antique
Les théâtres antiques se trouvaient généralement dans des villes ou dans des sanctuaires. Ils ont entretenu avec l'agora ou le forum, avec les temples des dieux du panthéon traditionnel ou avec ceux consacrés aux empereurs et avec les autres édifices de spectacle (odéons, stades, amphithéâtres) des relations fonctionnelles dont l'appréhension est nécessaire à la compréhension du rôle tenu par les monuments dans l'urbanisme, dans la religion et plus généralement dans la société antique. On favorisera donc le classement de complexes monumentaux comprenant des théâtres ou des amphithéâtres, plutôt que celui d'édifices isolés de leur contexte.
5 avoir conservé son authenticité
Les théâtres et les amphithéâtres n'ont pas seulement été restaurés au même titre que d'autres vestiges antiques. Depuis le XIXe s. l'habitude s'est prise de les réhabiliter pour recevoir des spectacles modernes. Ces réhabilitations ont souvent été très dommageables car les édifices antiques ne sont pas adaptés aux exigences des spectacles contemporains. Beaucoup ont déjà disparu sous les constructions de gradins et d'estrades modernes, de rambardes de sécurité et d'échafaudages destinés à porter l'éclairage ou la sonorisation. Certains édifices, pourtant bien conservés, ont ainsi été exclus du corpus des monuments pouvant être l'objet d'études scientifiques. Il serait souhaitable que le classement au patrimoine mondial non seulement n'accélère pas les réhabilitations abusives de monuments de spectacle, mais privilégie au contraire les édifices qui soit n'ont pas été restaurés, soit ont été l'objet de restaurations visant à expliciter leurs singularités antiques et non à les gommer par l'adjonction d'un équipement de salle de spectacle moderne.
6 avoir un bon état de conservation général
De nombreux édifices présentent des états de conservation très différents de leurs parties constitutives. Le théâtre d'Épidaure, par exemple, a un koilon remarquablement conservé et un bâtiment de scène dans un état médiocre, alors que celui d'Orange présente au contraire un mur de scène préservé sur 38 m de hauteur et des gradins presque totalement ruinés. On favorisera, autant que possible, le classement d'édifices dont toutes les parties constitutives ont un bon état de conservation : façade périphérique, gradins, circulations ainsi que, pour un théâtre, le bâtiment de scène et, pour un amphithéâtre, les salles de services sous l'arène.
7 être associé à des documents qui font connaître l'histoire de son utilisation
Les monuments ne sont pas seulement connus par leurs vestiges, mais par des documents archéologiques, littéraires ou épigraphiques, qui leur sont associés et qui permettent de préciser l'histoire de leur construction, de leur utilisation et de leurs transformations. On dispose pour certains édifices de comptes de constructions, de dédicaces, d'inscriptions mentionnant des réparations ou des aménagements, de textes, enfin, qui informent sur les spectacles dont ils ont été le cadre. C'est au Colisée que furent données les représentations commémorées par Martial dans le premier livre de ses Épigrammes et dans l'amphithéâtre de Lyon que fut martyrisée Blandine. C'est pour le théâtre du sanctuaire de Dionysos à Athènes, que furent écrites la plupart des pièces d'Eschyle, de Sophocle, d'Euripide et d'Aristophane qui sont conservées et qui sont devenues des oeuvres majeures de notre culture littéraire. Le souvenir de ces divers spectacles devra être pris en compte pour le classement.
|Jean-Charles MORETTI||Lyon, décembre 1999|
Bernardi Ferrero, D. de (1966-1974), Teatri classici in Asia Minore I (1966); II (1969); III (1970); IV (1974), "L'Erma" di Bretschneider, Rome.
Bieber, M. (1961), The History of the Greek and Roman Theater, 2e éd., Princeton University Press, Princeton.
Blume, H.-D. (1984), Einführung in das antike Theaterwesen, 2e éd., Wissenschaftliche Buchgesellschaft, Darmstadt.
Cianco Rossetto, P., Pisani Sartorio, G. (éds) (1994-1996), Teatri greci e romani alle origini del linguaggio rapresentato, Edizioni Seat, Rome.
Courtois, C. (1989) Le bâtiment de scène dans les théâtres antiques de l'Italie et de la Sicile. Étude chronologique et typologique, Université catholique de Louvain, Louvain.
Frézouls, Ed. (1982), « Aspects de l'histoire architecturale du théâtre romain », Aufstieg und Niedergang der Römischen Welt, II, 12, , de Gruyter, Berlin - New York, p. 343-441.
Golvin, J.-Cl. (1988), L'amphithéâtre romain, Essai sur la théorisation de sa forme et de ses fonctions, De Boccard, Paris.
Gros, P. (1996), L'architecture romaine, 1. Les monuments publics, Picard, Paris.
Mitens, K. (1988), Teatri greci e teatri ispirati all'architettura greca in Sicilia e nell'Italia meridionale c. 350-50 a.C., "L'Erma" di Bretschneider, Rome.
Pöhlmann, E. (1995), Studien zur Bühnendichtung und zum Theaterbau der Antike, Studien zur klassischen Philologie, 93, Peter Lang, Francfort.
The Urban Architectural Heritage of Latin America
|By Ramón Gutiérrez, Director, CEDODAL
(Centro de Documentación de Arquitectura Latinoamericana, Buenos Aires, Argentina)
LATIN AMERICA is made up of a large group of countries that possess characteristics of cultural identity in common but which at the same time are acknowledged to be very different. They grew up on the ancient pre-Columbian cultures that had developed in Mesoamerica in the north and in the Andean region in the south and were the most part unified under Spanish and Portuguese control in the 16th-19th centuries.
The architectural and urban heritage given special recognition by the UNESCO World Heritage Convention embraces examples from this colonial period, when the different countries were integrated into the organization of the Spanish Empire under several Viceroyalties, or in the case of Brazil as a dependency of Portugal. Whilst Cuba and Puerto Rico remained under Spanish rule until the end of the 19th century, the other countries achieved independence during the first quarter of that century.
An overall criterion that reflects the special cultural characteristics of each of the countries should not fail to consider, as UNESCO already has, the importance of this process of European and indigenous cultural integration that took place during the three centuries of Spanish and Portuguese rule.
However, in a more over-arching perspective the possibility should not be overlooked of incorporating those characteristics developed by the Latin-American countries since achieving their independence in the 19th century, when under the influence of new immigration, internal development, or integration into world commerce they received and assimilated new cultural inputs to their own heritages. This study of the importance of complementing the selection of monuments and sites already inscribed on the World Heritage List is carried out against this background, in order to include the evaluation of single groups that comply with the requirements of excellence and secure protection in the respective countries.
[Note This study was carried out by Dr Gutiérrez in 1997-98 and has been used by ICOMOS in its work as professional advisor to the UNESCO World Heritage Committee since that time.]
These historic centres are without doubt favoured heritage sites, which has resulted in their inscription. However, management of them varies between the different countries, and so it is possible to postulate certain sites within the heritage hierarchy that have not been evaluated effectively, as in the case of the historic centres of Arequipa, Trujillo, Ayacucho, and Cajamarca in Peru or Cuenca in Ecuador. Historic centres need, moreover, a clear preservation strategy on the part of local authorities, the delineation of protection areas, and at the same time the sanction and implementation of preventive measures in order to ensure better stability for these areas. Once historic centres have been declared to be part of the World Heritage there should be a system of monitoring to confirm the continuity of such measures irrespective of periodic political changes at national or local level. The process of increasing population density and urban decay in some of these historic centres that are already on the World Heritage List calls for social and cultural responses that permit the proper use of public open spaces and the recovery of a sizeable heritage that is menaced as a result of a lack of resources on the part of municipalities or national cultural agencies. Strategies for functional regeneration and recycling, the generation of diversifying activities, the encouragement of cultural tourism, and other means of improving the quality of life of the people have made outstanding contributions to the resurgence of historic centres, as can be seen in the case of Quito or more recently in Lima. In other cases urban renewal policies and expulsion of inhabitants can have a serious effect on the heritage, as in the case of Salvador/Bahia (Brazil). Historic centres that are largely made up of 19th century architecture, whether as a result of renewal of the buildings or the creation of new towns, have not so far been recognized by World Heritage inscription. However, they are very clearly typical of some towns of high heritage value, made up of architectural groups from the 18th-20th centuries, as is the case in Buenos Aires or some 19th century towns with substantial evidence of this nature, such as Valparaiso (Chile), Matanzas (Cuba), or Petrópolis (Brazil). It is also important to rescue the urban planning ideas of the 19th century and, in the same way that 20th century thought has been recognized in Brasilia, La Plata (Argentina) should be regarded as a recent urban foundation which drew upon 19th century academic ideas for the layout of diagonal streets, urban parks, and the concept of aesthetic structure in the monumental axes, as well as in the public buildings resulting from an international competition held in 1882. Although UNESCO has recognized several of the towns of this type, such as Guanajuato or Zacatecas (Mexico) or Potosí (Bolivia), these are intermediate towns that have experienced historically a strong continuity for reasons that lie outside their cyclical economic phases. Other mining communities such as Zaruma (Ecuador) and Taxco (Mexico) might be worthy of recognition. Other examples, such as Ouro Preto in Minas Gerais (Brazil), represent smaller towns that relate better to a system of towns integrated by a regional production process and which developed in the same historical period. They are all characterized by a lack of religious houses and by a wealth of parish churches or guilds that typify the mining boom of the 18th and early 19th centuries. In this case it would be sufficient to restrict the criterion for nomination to those towns that maintain high standards of excellence with regard to the heritage and which could also be integrated into a cultural tourism circuit. For example, in the case of Ouro Preto and the Sanctuary of the Bom Jesús at Matozinhos, it would be worth while incorporating Tiradentes, Mariana, and Diamantina. The same applies to the proposed nomination of the Sanctuary of Copacabana (Brazil), where, alongside the undeniable value of the Sanctuary itself, there is the whole policy of creating centres for indigenous converts (reducciones) around Lake Titicaca which resulted in 16th century settlements and high-quality churches, both on the Peruvian side (Juli, Pomata, Zepita, Acora, etc) and on the Bolivian side (Laja, Huaqui, Calamarca, Machaca, Tiahuanaco, etc). It is proposed also to introduce groups of towns that represent forms of settlement connected with trade routes and with the conversion of the Indians. The Indian villages in the Humahuaca gorge and the Calchaquíes valleys (Argentina), those of Chipaya and the Oruro area (Bolivia), the doctrinero villages of Paraguay, or those founded by Bishop Vasco de Quiroga in the Michoacán area (Mexico) provide the possibility of recording these processes of territorial reorganization. There also 19th century village systems, such as those on the Chiloé islands in the far south of Chile or in the coffee-producing area of Colombia, which might facilitate an approach to new forms of settlement, management of production, high-quality local architecture, and individual landscape characteristics. It is necessary to move towards the systematic identification of groups of settlements, even though these may span more than one country (as was done for the Jesuit missions) and consider the possibility of nominating them as groups while at the same time expanding the 19th century base. Although many of the main architectural monuments (Havana, Cartagena de Indias, San Juan de Puerto Rico, Portobelo, etc) are already on the World Heritage List, there is no doubt that they should be visited and understood as forming part of a vast offensive/defensive system which involves not only the great urban fortifications but also places on the coasts and islands, whether under Spanish, English, French, Dutch, or Danish rule. Between the 16th and 18th centuries the Caribbean was a region marked by the struggle for power between the great European nations, who expended vast sums of money in building these fortifications, which in many cases represent the most important heritage investments of a number of towns. For this reason the inscriptions of these architectural monuments should be made as part of a system so as to acknowledge their interaction with one another. Final comments on methodology In this connection the absence of 19th century heritage is very apparent and has required consideration of the recognition needing to be accorded to this cultural period. It is also evident from the tentative lists that it is necessary to identify with accuracy the groups of towns and historic sites that belong to the same system and which have similar value characteristics, so that nominations may be sufficiently broad. Finally, it is advisable that when considering works that are nominally of the 20th century there should be sufficient time elapsed for these to be evaluated in a wider context. The case of the Mexican architect Barragán, whose work has only been recognized in recent decades, illustrates the need for perspective and for not being pressurized by fashionable trends. For this reason it is recommended that architecture inscribed on the World Heritage List should in every case be the work of deceased architects, since this honour should be seen as something other than personal homage, which belongs to another form of recognition than World Heritage listing. At least half a century should elapse after the completion of a building for it to be analysed in a proper perspective in the context of the overall product of the period. Once again, it is necessary to stress that the identification of those ensembles that might be worthy of inscription does not preclude alternative approaches nor does it exhaust the possibilities of what might be considered to be of World Heritage quality. Nor is the presence or absence of adequate provision for legal measures or decision-making at local or national level for the protection and management of this heritage taken account of in this study, which has been based on approaches that are artistic, architectural, urban, cultural, and social, or of the potential for improvement and use of these ensembles. They need to be analysed once each country has undertaken the preparation of the proper measures. What follows has been prepared for each of the countries where outstanding examples have been identified. Among these, various situations have been studied according to the type of heritage and their intrinsic quality. In each country examples from the colonial period are given first, leading up to 19th century cases, where these exist. The lists below contain examples of historic centres, intermediate and small towns, groups of villages, and groups of architectural works treated as systems. Each of these groups obviously includes works from different periods and so they are attributed to the period that predominates within the group. No account is taken in this study of individual architectural monuments. It is thus a list that is indicative in character, aimed at producing a cross-section of the features that may be considered to represent the Latin- American cultural heritage.
T HE CENTRALIZING CONCEPT that began with the creation of the Plaza Mayor as the urban generator from the first third of the 16th century in the creation of Spanish towns served to accumulate official functions and to establish a hierarchy for the central areas of the main towns in the Americas. This is reflected in the appearance, the variations in urban fabric, and the growth of an urban landscape that has been given basic recognition in those inscriptions made on the World Heritage List up to the present.
H ISTORIC TOWNS probably represent one of the most important heritage resources on the American continent. These are generally ancient foundations which were marginalized by urban development processes or reacted to the apogee of finite productive cycles (principally mining) and then fell into decay when their productive resources dried up.
Integrated architectural groups
T HE MOST OUTSTANDING example of this form of territorial evaluation, connected with the encouragement of cultural tourism circuits, which would permit the integrated use of this heritage, is without doubt the fortifications of the Caribbean region.
T HE CENTRAL IDEA behind this new approach firmly ratifies the concepts of quality and excellence that have directed inscriptions on the World Heritage List, but it also seeks to approach these criteria in a form that is representative of the cultural property that characterizes each region, and in particular in the present case the Latin-American continent.
Properties to which priority should be given
These historic centres are without doubt favoured heritage sites, which has resulted in their inscription. However, management of them varies between the different countries, and so it is possible to postulate certain sites within the heritage hierarchy that have not been evaluated effectively, as in the case of the historic centres of Arequipa, Trujillo, Ayacucho, and Cajamarca in Peru or Cuenca in Ecuador.
Historic centres need, moreover, a clear preservation strategy on the part of local authorities, the delineation of protection areas, and at the same time the sanction and implementation of preventive measures in order to ensure better stability for these areas. Once historic centres have been declared to be part of the World Heritage there should be a system of monitoring to confirm the continuity of such measures irrespective of periodic political changes at national or local level.
The process of increasing population density and urban decay in some of these historic centres that are already on the World Heritage List calls for social and cultural responses that permit the proper use of public open spaces and the recovery of a sizeable heritage that is menaced as a result of a lack of resources on the part of municipalities or national cultural agencies.
Strategies for functional regeneration and recycling, the generation of diversifying activities, the encouragement of cultural tourism, and other means of improving the quality of life of the people have made outstanding contributions to the resurgence of historic centres, as can be seen in the case of Quito or more recently in Lima. In other cases urban renewal policies and expulsion of inhabitants can have a serious effect on the heritage, as in the case of Salvador/Bahia (Brazil).
Historic centres that are largely made up of 19th century architecture, whether as a result of renewal of the buildings or the creation of new towns, have not so far been recognized by World Heritage inscription. However, they are very clearly typical of some towns of high heritage value, made up of architectural groups from the 18th-20th centuries, as is the case in Buenos Aires or some 19th century towns with substantial evidence of this nature, such as Valparaiso (Chile), Matanzas (Cuba), or Petrópolis (Brazil).
It is also important to rescue the urban planning ideas of the 19th century and, in the same way that 20th century thought has been recognized in Brasilia, La Plata (Argentina) should be regarded as a recent urban foundation which drew upon 19th century academic ideas for the layout of diagonal streets, urban parks, and the concept of aesthetic structure in the monumental axes, as well as in the public buildings resulting from an international competition held in 1882.
Although UNESCO has recognized several of the towns of this type, such as Guanajuato or Zacatecas (Mexico) or Potosí (Bolivia), these are intermediate towns that have experienced historically a strong continuity for reasons that lie outside their cyclical economic phases. Other mining communities such as Zaruma (Ecuador) and Taxco (Mexico) might be worthy of recognition.
Other examples, such as Ouro Preto in Minas Gerais (Brazil), represent smaller towns that relate better to a system of towns integrated by a regional production process and which developed in the same historical period. They are all characterized by a lack of religious houses and by a wealth of parish churches or guilds that typify the mining boom of the 18th and early 19th centuries.
In this case it would be sufficient to restrict the criterion for nomination to those towns that maintain high standards of excellence with regard to the heritage and which could also be integrated into a cultural tourism circuit. For example, in the case of Ouro Preto and the Sanctuary of the Bom Jesús at Matozinhos, it would be worth while incorporating Tiradentes, Mariana, and Diamantina.
The same applies to the proposed nomination of the Sanctuary of Copacabana (Brazil), where, alongside the undeniable value of the Sanctuary itself, there is the whole policy of creating centres for indigenous converts (reducciones) around Lake Titicaca which resulted in 16th century settlements and high-quality churches, both on the Peruvian side (Juli, Pomata, Zepita, Acora, etc) and on the Bolivian side (Laja, Huaqui, Calamarca, Machaca, Tiahuanaco, etc).
It is proposed also to introduce groups of towns that represent forms of settlement connected with trade routes and with the conversion of the Indians. The Indian villages in the Humahuaca gorge and the Calchaquíes valleys (Argentina), those of Chipaya and the Oruro area (Bolivia), the doctrinero villages of Paraguay, or those founded by Bishop Vasco de Quiroga in the Michoacán area (Mexico) provide the possibility of recording these processes of territorial reorganization.
There also 19th century village systems, such as those on the Chiloé islands in the far south of Chile or in the coffee-producing area of Colombia, which might facilitate an approach to new forms of settlement, management of production, high-quality local architecture, and individual landscape characteristics.
It is necessary to move towards the systematic identification of groups of settlements, even though these may span more than one country (as was done for the Jesuit missions) and consider the possibility of nominating them as groups while at the same time expanding the 19th century base.
Although many of the main architectural monuments (Havana, Cartagena de Indias, San Juan de Puerto Rico, Portobelo, etc) are already on the World Heritage List, there is no doubt that they should be visited and understood as forming part of a vast offensive/defensive system which involves not only the great urban fortifications but also places on the coasts and islands, whether under Spanish, English, French, Dutch, or Danish rule.
Between the 16th and 18th centuries the Caribbean was a region marked by the struggle for power between the great European nations, who expended vast sums of money in building these fortifications, which in many cases represent the most important heritage investments of a number of towns. For this reason the inscriptions of these architectural monuments should be made as part of a system so as to acknowledge their interaction with one another.
Final comments on methodology
In this connection the absence of 19th century heritage is very apparent and has required consideration of the recognition needing to be accorded to this cultural period. It is also evident from the tentative lists that it is necessary to identify with accuracy the groups of towns and historic sites that belong to the same system and which have similar value characteristics, so that nominations may be sufficiently broad.
Finally, it is advisable that when considering works that are nominally of the 20th century there should be sufficient time elapsed for these to be evaluated in a wider context. The case of the Mexican architect Barragán, whose work has only been recognized in recent decades, illustrates the need for perspective and for not being pressurized by fashionable trends.
For this reason it is recommended that architecture inscribed on the World Heritage List should in every case be the work of deceased architects, since this honour should be seen as something other than personal homage, which belongs to another form of recognition than World Heritage listing. At least half a century should elapse after the completion of a building for it to be analysed in a proper perspective in the context of the overall product of the period.
Once again, it is necessary to stress that the identification of those ensembles that might be worthy of inscription does not preclude alternative approaches nor does it exhaust the possibilities of what might be considered to be of World Heritage quality. Nor is the presence or absence of adequate provision for legal measures or decision-making at local or national level for the protection and management of this heritage taken account of in this study, which has been based on approaches that are artistic, architectural, urban, cultural, and social, or of the potential for improvement and use of these ensembles. They need to be analysed once each country has undertaken the preparation of the proper measures.
What follows has been prepared for each of the countries where outstanding examples have been identified. Among these, various situations have been studied according to the type of heritage and their intrinsic quality. In each country examples from the colonial period are given first, leading up to 19th century cases, where these exist.
The lists below contain examples of historic centres, intermediate and small towns, groups of villages, and groups of architectural works treated as systems. Each of these groups obviously includes works from different periods and so they are attributed to the period that predominates within the group. No account is taken in this study of individual architectural monuments. It is thus a list that is indicative in character, aimed at producing a cross-section of the features that may be considered to represent the Latin- American cultural heritage.
A R G E N T I N A
|1||The towns of La Quebrada de Humahuaca and Puna Jujena (Province of Jujuy)|
This is a group of towns which grew out of the old encomiendas (estates) of the 16th and 17th centuries and the miners' settlements of the former Tojo Marquisate. These towns, which are located in the extreme north-west part of Argentina, close to the Bolivian border, are within two clearly delineated geographical zones, the Humahuaca pass and the Jujena puna (high plateau).
Most of these villages have considerable architectural unity resulting from slow consolidation and growth. In all of them, the church is the focal point from both the urban and the architectural standpoint. The church provides the basic configuration of several of these villages, among them San Francisco de Yavi and Purmamarca, both of which were built in the 17th century and are listed national historical monuments. The same can be said of many of the 18th century churches, some of which received additions or were modified in the 19th century. Among them are Humahuaca, Uquia, Huacalera, Tilcara, Tumbaya and Tafna, along the road leading from Upper Peru (today Bolivia) to Río de la Plata.
The chapels and villages of Coranzuli, Susques, Casabindo, and Cochinoca provide an idea of the scale of the stretches of land occupied on the Jujena high plateau. All of these places of worship have unique features, ranging from their atria with posas (small chapels used during processions) to artistic treasures of paintings and religious imagery. Some of the wall paintings are of particular interest.
The entire group may be appreciated for its qualities in terms of heritage, and also in terms of its location and the way it fits in with the landscape. Nearly all these chapels are protected as a result of their status as listed historic monuments, and the majority have been restored recently.
|2||The Jesuit estancias (Province of Córdoba)|
The Jesuits established an effective economic system in the central region of Argentina to provide for their schools, university, and novitiate. These estancias included churches built in the 17th and 18th centuries, together with living quarters and other buildings. A number of these estancias, such as Alta Gracia, comprised a large reservoir and dwellings which later on would be occupied by Virrey Liniers. Adjacent to the Jesús María estancia is an interesting 18th century postal building known as the Sinsacate Post Office.
The most isolated and probably the oldest is the Candaleria estancia, while the Santa Catalina estancia is the largest. The Caroya estancia, which was the last one built in the 18th century, was used for the manufacture of guns during the War of Independence.
The churches and cloisters house some noteworthy examples of religious imagery. Worthy of mention are those in the Jesús María Museum, at the estancia of the same name. All the buildings referred to are listed historic monuments and as such benefit from special protective measures. As in the preceding case, the value of the entire group of estancias exceeds the individual value of each taken separately.
INSCRIBED ON THE WORLD HERITAGE LIST IN 2000
|3||The villages of the Calchaquies Valleys (Province of Salta)|
Although they were founded in the 17th and 18th centuries, a substantial number of these villages underwent further growth and changes in the first half of the 19th century. Set in a spectacular landscape, the villages were dependent upon haciendas (country estates) or encomiendas(concessions). The oldest village in the group, San Pedro Nolasco de Molinos, is no exception. The chapels at these estates and the oratories at various locations along the roads were focal points for these villages, which are characterized by geographical and functional unity.
The villages of Cachi, Seclantás, Angastaco, San Carlos, and at a later date Cafayate are the embodiment of a strategy of land acquisition to the detriment of the Calchaquí Indians, who had long been settled in the area. The bitter conflicts lasted well into the 17th century.
The value of this rich heritage of both civil and religious architecture, comprising houses, haciendas, oratories, and churches, has been recognized by the Argentine Government by designation as a National Monument. At the present time 19th century vernacular architecture plays a dominant role, a number of buildings and large houses having been restored for the purpose of tourism.
|4||The town of La Plata (Province of Buenos Aires)|
La Plata was laid out in 1882 when Buenos Aires became the Federal Capital of Argentina. It was seen as the model for the new administrative city. Together with his architects, the most talented of whom were Juan Martín Burgos and Pedro Benoit, the Governor, Dardo Rocha, who spearheaded this urban project, worked with the aim of building a modern city in accordance with the latest criteria of European town planning. They accordingly made use of a structure comprising wide thoroughfares, monumental buildings, and diagonal avenues leading to public open spaces and small squares of various sizes. The town planning focused on geometrical principles and urban beauty, in the form of parks, the road connecting with the port, and the peripheral avenues.
The city grew rapidly but nevertheless was able until recent years to maintain the urban qualities incorporated into its original plan. An international architectural contest was organized for the design of the public buildings, most of which were in the event designed by German and Argentine architects. The buildings most worthy of note are the Municipal Palace, the House of the Government, the Parliament Building, the Museum, the Observatory, the Railway Station, the Pasaje Rocha, and the Cathedral.
The plan of La Plata, which was considered to represent a major breakthrough, exerted a considerable influence all over the continent. Some examples are the layout of Belo Horizonte (1897) in Brazil and the opening up of diagonal avenues in large capital cities such as Buenos Aires, Rio de Janeiro, and Montevideo. This is unquestionably the most significant 19th century urban plan anywhere in Latin America, and as such deserves the same recognition as that given by the World Heritage Committee to Brasilia for the 20th century.
|5||The monumental centre of Buenos Aires|
Known as the most European city in America, Buenos Aires, although founded in 1580, has only retained a handful of churches from the colonial period. It does, however, boast magnificent 19th century architecture, with buildings on a par with the most distinguished achievements of the Old World.
The construction in 1890 of the Avenida de Mayo, which opened up a wide boulevard on the same axis as the old Plaza Major of the city, was instrumental in defining the urban profile of this central part of the city, which coexists with the old colonial quarters in the southern part, now replaced by 19th century architecture which is considered to be the historic centre of Buenos Aires. It is necessary to consider the city with its 19th century monumental heritage which, though spread over a vast area, nonetheless depicts a series of large ensembles that together make up the city's image. Within this heritage one must recognize the integration of industrial architecture and that of the port. The embankments of Puerto Madero, which have been rehabilitated for use by service industries, exemplify this integration.
There are in fact few cities in Latin-America with such high- quality examples of 19th century architecture together with a large number of churches, most of which are from the 18th century.
The Avenida de Mayo, which runs over the continent's first underground railway line (1913), and many more outstanding buildings in the city are protected by the historic monuments legislation or by municipal ordinances. In some cases restoration or maintenance works have been carried out.
B O L I V I A
Of the various groups of monuments on the tentative list, the Copacabana Sanctuary and the community of Chipayas are worthy of consideration. However, these properties should be integrated within regional groupings of special value.
|1||The Copacabana Sanctuary and the region of Lake Titicaca (Bolivia and Peru)|
This is one of the most important areas of settlement, dating back to the 16th century, where there is also evidence of the presence of indigenous cultures, such as those of Tiahuanaco and the Lupacas as well as the Incas. Despite its outstanding character, the Copacabana Sanctuary forms an integral part of a system of diocesan villages which took shape around the shores of Lake Titicaca.
The towns of Carabuco, Calamarca, Machaca, Viacha, Tiahuanaco, Huaqui, and Laja in Bolivia provide churches and other examples of vernacular architecture of outstanding architectural and artistic value. Equally, on the Peruvian side in the vicinity of Chucuito, the churches of Juli, Pomata, Paucarcolla, Llava, Acora Zepita, Puno, Ayaviri, Asillo, Lampa, Umachiri, Oruillo, and elsewhere, built between the 16th and 18th centuries, are of noteworthy quality. Their mural paintings, sculptures, furniture, and silver ornaments all bear witness to the region's heritage of exceptional expressiveness. In addition to all these elements there are also many archaeological sites, such as the Chulpas de Sillustani.
It is recommended that this entire ensemble should be considered as a whole, in so far as it reflects the historical development of the area and the common history of the various elements. It would not seem logical to designate Copacabana on its own, thus setting aside, for instance, the four splendid churches in the village of Juli.
|2||Chipayas and the Oruro region|
Although the Chipayas settlements possess some peculiarities in terms of the configuration of the houses and the structure of the town itself, they nonetheless have a structural relationship with other settlements in the same region of Bolivia. This applies to the towns of Caquiaviri, Corque, Curahuara de Caragas, Paria, Ancocala, Yarvicolla, Sepulturas, Totora and many others dating back to the end of the 16th century during the period of the reducción, when Indian villages were created by the Spanish missionaries to convert the Indian population to Christianity. These villages have kept their characteristic layout comprising the square, the church and its atrium, and small posa chapels.
Any nomination should include all these monuments which together give the area its special character. Special attention should be given to the quality of these various properties, which include wall paintings and religious ornamental objects.
B R A Z I L
It is considered to have been a mistake not to have included the city of Alcantara in the nomination of São Luis do Maranhão, since these two cities are located adjacent to one another.
|1||All the towns of Minas Gerais|
Ouro Preto and the Sanctuary of Bom Jesús de Matozinhos have already been inscribed on the World Heritage List. There is a case to be made for extending this, to include the towns of Tiradentes, Mariana, Diamantina, San João de Rey, and Sabará, which together form important ensembles from the 18th and 19th centuries that are worthy of forming part of a serial inscription, because of their specific form of land occupation and the mining activity of this region. Furthermore, these villages include monuments and outstanding architectural and artistic heritage which are the object of an in-depth maintenance and restoration campaign by the National Department for Historical and Artistic Heritage (SPHAN). There is also very well integrated architecture and the links with the surrounding landscape and environment are of high quality.
|2||The city of Pétropolis|
This is another interesting urban unit built in the 19th century (1840), centred on the Imperial Palace, the residence of the only European royal family to have settled in South America. The layout of the town conforms organically to the topography, reflecting the traditions of Portuguese town planning in its ability to fit in well with the landscape (even though the town was laid out by a German, Julius Koeller).
The academic architecture of Pétropolis, which includes a number of structures of historical interest, makes it a town that is of interest in terms both of its mid-19th century construction and of its specific urban functions. Pétropolis could be nominated as a further example of the type of urban layout already identified in the case of La Plata (Argentina) and also to be found in other 19th century cities, such as Valparaiso (Chile).
C H I L E
|1||The chapel and towns of the Chiloe Islands (Southern Chile)|
This is a large series of churches, most of which are of wooden construction and which the Jesuits began building in the 18th century, although the great majority were constructed in the 19th century.
The Jesuits applied the concept of itinerant missions, which on certain of the small islands of the archipelago took the form of a number of chapels around which hamlets had to be built. The centre of evangelization was the Colegio located in the town of Castro. Following the expulsion of the Jesuits in 1767, most of these chapels were taken over by members of the Franciscan order of Propaganda Fide, which continued the established practice of itinerant missions.
There are several dozen of these churches, from the old church of Achao to the 19th century Castro Cathedral. They illustrate wood construction techniques and high-quality solutions for the use of space and are unique specimens within the context of architecture in the Americas. Among them, those of Rilán, Dalcahue, Nercón, Quinchao, Chonchi, and Vilipulli are particularly worthy of note.
In recent years the painstaking restoration and maintenance of the chapels by a group of architects with private backing has made it possible to improve the conservation of this heritage substantially.
THE CHURCHES OF CHILOE WERE INSCRIBED ON THE WORLD HERITAGE LIST IN 2000
|2||The historic centre of Valparaiso|
Valparaiso, the largest port in Chile and the present seat of the Parliament, was founded in the 16th century but only grew slowly until well into the 18th century. It is, moreover, one of the cities in which the architectural heritage of the 19th century is the best expressed anywhere on the continent.
The squares of the city (Matriz, Municipalidad, and Aduana) make up, together with the area of the port, a sequence of highly interesting spaces brimming with vitality. The urban grid is also an important element which has endured over time.
At a time when further construction seems to have reached a standstill in many countries of the American continent, due to a lack of resources arising from long wars and internal strife, Valparaiso succeeded in consolidating its position as a city of classic architectural design, built according to a model characterized by the influence of the burgeoning Anglo- Saxon population, which has left an indelible mark here. In the first place, this architecture is distinct from its counterparts, inspired by French and Italian academicism, in many of the cities of the Southern Cone, expressing itself by means of the use of wood and metal cladding in the context of very original solutions.
The situation of the city, along a narrow coastal strip, made it necessary to build on the steep topography of the cerros, resulting in a spectacular cityscape. This has given the city some breathtaking panoramas in a number of areas.
In terms of both the value of its architecture and that of its atmosphere and the cityscapes that it provides, Valparaiso, along with La Plata, Buenos Aires, and Pétropolis, composes the most significant collection of 19th century urban architecture in South America, spanning its various nuances and periods.
C O L O M B I A
|1||The historic town centre of Tunja|
Although in recent years the centre of Tunja has fallen victim to construction work without proper control measures, this town nonetheless conserves the only surviving 16th houses in South America, as well as a very interesting Plaza Mayor (Central Town Square).
Along with a number of important churches from the 16th to 18th centuries, such as the Cathedral, the Churches of Santa Bárbara, Santa Clara, Santo Domingo (with its Chapel of the Rosario), San Ignacio, San Agustín, San Lázaro, El Topo, and San Francisco, the houses of Rendón el Fundador and that of Escribano Vargas with its magnificent mural paintings constitute an outstanding artistic heritage.
These churches and houses, which are protected as Historic Monuments, have in the past ten years undergone maintenance and restoration work (including the mural paintings) and in general are in very good condition.
|2||The historic town centre of Santa Fe de Antioquoia|
This is another example of an intermediate-sized city possessing a high-quality and relatively homogeneous regional architecture with buildings of a monumental character, among them the late 18th century Cathedral and the old Jesuit Church of Santa Bárbara.
Santa Fe de Antioquia was founded in 1546 and its subsequent development was very slow until the 18th century, when it became a major commercial centre in the region. The buildings constructed during these periods, which include a number of very interesting large houses, have since 1959 been protected by legislation (the Organic Law for the Colonial Monuments of Colombia). However, there is need for there to be some amendments to the urban ordinances. To this end, a number of different studies have been conducted by academic specialists.
The homogeneous nature of the city centre and the high quality of the urban landmarks are such that it is recommended that Santa Fe de Antioquia be considered for inclusion on the List.
|3||Villages of the coffee-producing area (Antioquia and Caldas)|
The small towns in these regions of Colombia resulted from 19th century colonization. They are characterized by domestic architecture that makes use of highly detailed carved wood.
A number of these towns, such as Jericó, have both a Franciscan and a Claretian church. Titiribi with its Girardot Circus-Theatre and the large complexes of Salamina and Aguadas have been declared National Historic Monuments.
To this list might also be added the towns of Jardín, Montenegro (with its National Coffee Museum), Venecia, Santa Rosa de Osos and Armería, whose inhabitants are fully aware of the value of the towns in which they live.
In this way it would be possible to pay tribute to one of the principal processes of colonization, based on coffee production. This would establish a very clear relationship between the respective functions of the urban and rural settlements, which bear witness to the establishment of a territory and its source of economic wealth. This architecture with its vernacular features equally reflects refinements in execution and a sense of integration which make it truly unique anywhere in the Americas.
C U B A
|1||The historic centre of Camagüey|
Camagüey is one of the towns of the island of Cuba which in recent years has received the greatest attention from that country's agency for the Architectural and Urban Heritage.
Camagüey has undergone significant modifications on three occasions since it was founded in the 16th century under the name of Santa María del Puerto Principe. It does not conform with the traditional Hispanic quadrilateral urban layout, but rather has been more spontaneous in its formation, thereby clearly setting itself apart from other towns. An pattern of narrow streets developed here linking open spaces with the various urban landmarks, such as churches, convents, and hospitals which in turn give a structure to the quarters of this historic town centre, one of the largest in Cuba.
The historic centre comprises a series of 18th century monuments, among which of particular interest are the churches of La Matriz, San Juan de Dios (including a hospital), La Merced, La Soledad, and Santo Cristo del Buen Viaja. The church of Santa Ana dates back to the 17th century and those of San Lázaro and El Carmen were built in the 19th century. Nearly half the buildings in the central part of Camagüey date from the 18th and 19th centuries, and this accounts for the visual impact of its homogeneous cityscape, which includes high-quality colonial houses.
|2||The historic centre of Matanzas|
The city of Matanzas has one of the most interesting 19th century historic centres anywhere in the region. It should be pointed out that Cuba remained under Spanish control until 1898, and so the buildings here reflect a neo-classicism directly linked with the buildings constructed in Spain until the end of the 19th century.
The Teatro Sauto, the various residences, the churches, and the notable 19th century Botica (Pharmacy), along with the streets and small squares, give Matanzas a unique urban expression which is a living tribute to the romantic iconography of the 19th century.
The social and economic reality of the island is nevertheless such that new types of solution must be found to protect this town. Its architectural heritage is of a rare quality, finding expression both in the typology of the houses with stained glass windows and the adjoining grillwork and in the environmental improvement of the part of the town built facing the river.
Matanzas is yet another example of a 19th century historic town centre deserving of this distinction in order to secure the continuity of a strategy for preservation and environmental control, the various social measures for which still remain pending.
|3||The group of fortifications in the Caribbean region|
Although this proposal has already been put forward at the meeting held in Cartagena de Indias (Colombia) in 1996, a number of separate nominations have also been made by States Parties to the Convention for individual components of this system. It is repeated here under the heading of Cuba because some of the fortifications in Havana are already on the List and those in Santiago de Cuba are currently under consideration.
It would be advisable to adopt an overall approach to these defensive/offensive systems, which include a number of sites already on the List (Portobelo, Cartagena de Indias, Havana, Santo Domingo, etc). Such an approach would include properties in a number of former Spanish colonies and also English, French, and Dutch colonies. To this end, the studies compiled by CARIMOS and the OAS, as well as Ramón Paolini's book Fortificaciones del Caribe, illustrate the location and the quality of these fortifications dating from the 16th to the 19th centuries.
E C U A D O R
|1||The town of Zaruma|
Zaruma came into being as a mining town in the 16th century and grew considerably as a result of the production of the mines. It is located on rugged terrain and has grown in an organic way, resulting in high-quality townscapes. The greater part of the town was renovated in the 19th century. The growth of agriculture in the region in the 17th century consolidated this mining town and gave rise to a boom period which drew to a close in the 18th century. However, this changed in the late 19th century, when Zaruma Gold and later the South American Development Company established operations here, initiating the renewal of the town.
The relationship between the town and the surrounding landscape, coupled with its isolation, have enabled the town to retain its homogeneous appearance and to be recognized for its historic and cultural expression. In view of the continuous mining activity, now in decline, and a 16th century urban fabric and townscape that were modified in the 19th century, Zaruma can justly be considered as an important example of historical events viewed within the broader Latin American context.
|2||The historic centre of Cuenca|
Cuenca was founded in 1557 on the former site of the Inca settlement of Tomebamba and is today a good-sized town in the mountains of Ecuador. The Plaza Mayor and the Plaza de San Francisco are public spaces which still contain important architectural monuments such as the old Matrizand a number of churches. The enclosed Conception Monastery has preserved a rich artistic heritage, including 18th century wall paintings. Cuenca has retained its homogeneous vernacular architecture, making use of indigenous materials and the techniques appropriate to them.
These factors resulted in 1982 in the National Institute for Cultural Heritage in Ecuador protecting the historic centre of Cuenca by establishing the concept of archaeological areas (Todos Santos), the special area, with primary protection areas and buffer zones.
The conservation of the magnificent area of natural landscape of the Barranco (steep valley) of the Tomebamba River and the restoration of the Casa de Chaguarchimbana undertaken recently provide evidence of this growing concern for the heritage of Cuenca.
INSCRIBED ON THE WORLD HERITAGE LIST IN 1999
G U A T E M A L A
|1||The town of Chichicastenango|
Amongst the many indigenous towns of Guatemala which reflect the process of organization of colonial space, Chichicastenango additionally embodies a number of specific factors, such as traditions which have endured, a large Sunday market, the lively character of the sanctuary, and an incomparable architectural and urban heritage.
The 18th century church of Chichicastenango century has retained its elevated atrium and the posas (small chapels) in the corners of the open square, ie the pristine structure of the Indian village. The popular architecture here consists of homogeneous spaces where the vitality of the indigenous people reflects both a strong feeling of the present and a deeply rooted historical and cultural heritage.
M E X I C O
|1||Patzcuaro and the villages of Michoacan|
The villages founded in the 16th century by Bishop Vasco de Quiroga in the Michoacan region together make up one of the most important social and cultural experiments anywhere in the Spanish colonies of the Americas. Taking his inspiration from the principles set out by Thomas More in his Utopia, Vasco de Quiroga created a series of hospital-villages (guataperas) to protect the indigenous people from the greed of his own compatriots, making sure that the various communities specialized in different manual trades.
From his episcopal see in Patzcuaro, the Bishop laid out a noteworthy urban design that integrated small squares and public spaces, and sought to build his Cathedral at the centre along the lines of the ideal cities of Renaissance humanism.
Other towns such as Tzin-Tzun-Tzan ("Place of the Humming Birds") still have their 16th century churches with open chapels, accommodation for converts undergoing instruction, and other open spaces which bear witness to the extent of this experiment. Uruapan and Tiripetío, with their churches covered with wall paintings, Chapitiro, Tócuaro, Uricho, Santa Fe de la Laguna, Paracho, Santa Clara, Jaracuiro, etc provide a significant understanding of the regional breadth of this unique project, comparable with the Jesuit missions of Paraguay in their social and cultural aspects.
|2||The historic centre of Tlaxcala and the Sanctuary of Ocotlan|
Tlaxcala is a town in which a number of important 16th century monuments, including the Casas Reales, the Cathedral, and the Church of San Francisco with its distinctive mudéjar wooden ceiling, have survived. Its public spaces and other groups of monuments, such as the Palacio de Justicia (courthouse), make this town near Puebla a reference point in terms of Mexican architectural and urban heritage.
The Sanctuary of Ocotlan, located near Tlaxcala, is a masterpiece of the Mexican Baroque style. It was built in the 18th century and its red ceramic-covered towers stand out in stark contrast to the well proportioned white facade. Inside, the alcove of the Virgin is one of the finest examples of Baroque anywhere in the region.
The town and the Sanctuary are outstanding representatives of two great periods of Mexican architecture, the 16th and 18th centuries.
|3||San Miguel de Allende|
This historic centre is composed of high-quality buildings from the 18th and 19th centuries equal to those in Zacatecas or Guanajuato. Of particular note is the siting of this city, founded in 1542, in relation to its surrounding landscape. Many of the superb houses in this town are now in use for tourism. Among the most distinguished monuments are the homes of Ignacio Allende and the Counts of the Canal. Among the outstanding churches are those of San Francisco, Nuestra Señora de la Salud, the Oratory of San Felipe Neri, and the Santa Casa de Loreto, all built in the 18th century, and the 19th century Iglesia Parroquial (Parish Church).
The mining town of Taxco, which was founded in the 16th century, nowadays receives many tourists. Its location on uneven, rugged terrain and the spontaneous nature of the layout of the city has resulted in a highly picturesque settlement, even though in some areas of the town the houses are more often "seen from the rear." Among its monuments are the Church of Santa Prisca (1748-54), one of the foremost examples of Mexican Baroque architecture, which overlooks the town from its site perched on top of a hill in the centre of the town, making it a prominent monumental landmark.
The narrow streets of Taxco, its market places and its streets with stairways or ramps are all elements which, with their different spaces, contribute to the making of an urban atmosphere which is both pleasant and full of surprises and discovery. The residences of José de la Borda (Palacio Municipal) and the house of the painter Figueroa (now a museum) both date from the 18th century. Their interest is comparable with that of the house where Humbodlt lived in 1803, at present a store where local art and craftwork are sold.
P A R A G U A Y
Although Paraguay has begun taking steps to nominate the Carlos Antonio Railway Line to the World Heritage List, this is considered to be of far less interest than the groups of doctrinero villages. It is also felt that several more of the Jesuit mission villages should be added to the List.
|1||The Jesuit missions|
The missions of Trinidad and Jesús have already been included on the World Heritage List. In spite of some unfortunate work that has been carried out on it, the whole of San Cosme and Damián, which has kept its Colegio, should be included, as well as a part of what the Jesuits were able to complete before being expelled in 1767.
The villages of Santa Rosa should also be included. Here, with some minor modifications, the houses of the Indians, the Chapel of Loreto, and the remains of the tower as well as retablos and high-quality religious images still remain. The finest collections of Jesuit religious imagery are to be found in the villages of San Ignacio Guazú and Santa María de Fe; the Museum of the Missions is in the former. These missions should be included on the List in virtue of the fact that they form a unit.
|2||The doctrinero villages|
Not long after the city of Asunción was founded in 1537, a series of villages was created where the Christian doctrine was taught to the Indians of the estate by the Franciscans, who began evangelizing in the region. These villages, which were later handed over to secular clerics, are highly interesting examples of wooden architecture. A unique aspect of these settlements is that their churches are set in the middle of the main squares and not on one of the sides.
Most of the churches were rebuilt in the course of the 18th century using the same techniques of construction, and so in the villages there is a series of colonnaded churches and in some cases houses with wooden galleries in front, which deserve to be considered as a unique regional architectural solution. Among the most noteworthy churches are those of Yaguarón, Capiatá, Piribebuy, Valenzuela, Paraguarí, and Emboscada, the last-named founded in 1740 by former black slaves who were freed to serve as a defence militia against the warlike threats of the indigenous peoples. The architectural features of these various buildings are not simply limited to the internal (the church as a place of assembly) or external use of space, but also include artistic creation in the form of exceptional retablos and polychrome religious images.
P E R U
|1||The historic centre of Arequipa|
Located in the southern part of Peru and founded in 1540, Arequipa is one of the most interesting examples of architecture and urban planning in Latin America. It is possible here to identify the site of the ancient indigenous settlement, the grid of the Spanish town, and the reducciones(townships established subsequently for Indians converted to Christianity) of Yanahuara and Cayma which, though located on the other side of the river, now form part of the town itself.
The architecture of Arequipa displays some of the earliest examples of the mestizo Baroque style, to be found on the facade of the Compañia de Jesús (1698) and in the churches of Santo Domingo, La Merced, Santa Teresa, Santa Rosa, the Third Order of San Francisco, and other 18th century buildings. The monastery of Santa Catalina of Siena, which was opened to the public some ten years ago, is a prime example of a town within a town where the nuns lived in small "houses" or cells laid out along narrow inner streets behind a high wall.
The 18th century houses that remain in Arequipa are unique in their use of a local volcanic stone for construction. The indigenous character of these houses is shown by their large doors and windows. The houses of Tristán del Pozo, Moral, Iriberri, La Moneda (the Mint), etc embody first-class civil architecture.
The earthquakes of 1784 and 1868 had an effect upon the heritage of Arequipa in that they led to the birth of a classical architecture of high quality that integrated with the earlier Baroque buildings. The Cathedral, rebuilt following destruction by fire in 1844, is another important monument, the location of which on the arcaded Plaza de Armas is significant from a scenic point of view.
In Peru, historic monuments are protected by national legislation, and at present efforts are being made to improve the provisions for the protection of the historic part of Arequipa.
INSCRIBED ON THE WORLD HERITAGE LIST IN 2000
|2||The historic part of Trujillo|
Located in the northern coastal region of Peru, near the pre- Inca citadel of Chan Chan, which is one of the most interesting archaeological sites anywhere in the country and is inscribed on the World Heritage List, the town of Trujillo, founded in 1534, developed in a somewhat curious way owing to the oval layout of its late 17th century walls, the work of the Italian engineer Formento.
Trujillo has retained a large part of its colonial architectural heritage, especially that created during its apogee in the 18th century, when the Cathedral and the churches of San Francisco, El Carmen, Santo Domingo, La Merced, Santa Ana, Santa Clara, Belén, and the interior of the Church of San Agustín were built. On a par are the handsome 18th and 19th century mansions, which contribute to the homogeneity of the historic town centre of Trujillo. Large doors and patios, remarkable windows with extensive iron grilles, and buttresses and vestibules with mural paintings (which can also be seen here and there on the facades) make a number of houses stand out, among them those of Ganoza, the Marquis of Herrera and Valle, Urquiaga, and Marshal Orbegoso.
In recent years the historic centre has been the focus of restoration and improvement work, which has included the extensive use of colour in the area of the Plaza Mayor and on a number of the monuments.
Any proposal for the inscription of Trujillo on the World Heritage List should include the archaeological sites nearby.
|3||The historic centre of Ayacucho|
Ayacucho was founded around 1540 under the name of Huamanga; its present-day name comes from the battle that took place at a place nearby with this name, which gave Peru its independence and brought Spanish rule in South America to an end.
One of the peculiarities of the colonial architecture of Ayacucho, where 18th century buildings predominate, is undoubtedly the spacious nature of its houses and patios, along with the highly varied styles of its churches. The main residences - those of Garcia del Barco, the Marquis of Totora, the so-called "La Tres Máscaras" (The Three Masks), Ruiz de Ochoa, and the Marquis of Cabrera - are all of high quality. Among the religious buildings, the church of Santo Domingo with its open chapel in front, the late 17th century Cathedral, the Church of the Jesuits and its Colegio (the seat of the University), the churches of Buena Muerte, San Francisco de Paula, San Francisco de Asís, Santa Ana and Santa Clara, Santa Teresa with its magnificent mudéjar retablo, and the church of La Merced are all highly prized elements of the heritage which deserve to be given similar recognition to that accorded to those historic centres that are already on the List.
|4||The historic centre of Cajamarca|
The historic conquest of Peru which marked the fall of Atahualpa and the triumph of Francisco Pizarro was completed at the Inca city of Cajamarca. It was here that the Spaniards founded their new city, establishing a new urban profile but still keeping the historic centre, known as the Cuarto de Rescate (the Redemption Quarter).
The main buildings in this historical centre date from the 17th and 18th centuries, with churches rising above a series of sober and homogeneous houses with remarkable facades and craftsmanship in wood by local artisans. The Cathedral, with its interesting stone bosses, the Church of San Francisco, which is purported to be the oldest in the town, and the hospitals of Belén and La Recoleta give an idea of the high quality of the monumental works here, which deserve recognition as exceptional heritage in an intermediate-sized town.
|ANNEX II||Analysis of the World Heritage List and national tentative lists|
As a preparatory step in preparing the main report above, an analysis was made of properties inscribed on the World Heritage List, those included in tentative lists submitted by Latin-American States Parties to the Convention, and others considered to be worthy of consideration. This is presented below in tabular form.
Two points needs to be emphasized with regard to this table. First, it represents the initial approach to the study, the definitive recommendations of which are given in the main text above. Secondly, in general terms the properties in the tentative lists are adjudged to be acceptable for nomination to the World Heritage List.
São Luis do Maranhão
Conjunto minero (Diamantina, Tiradentes, Mariana)
Chiloe group (churches only)
Santa Fe de Antiquoia
Villa de Leiva
San Cristobal Casas
San Luis Potosí
San Miguel Allende
Colonia de Sacramento
Nueva Cadiz (ruins)
Two points needs to be emphasized with regard to this table. First, it represents the initial approach to the study, the definitive recommendations of which are given in the main text above. Secondly, in general terms the properties in the tentative lists are adjudged to be acceptable for nomination to the World Heritage List.
Potential fossil hominid sites for inscription on the World Heritage List - A Comparative Study, 1997
by Clive Gamble and Chris Stringer
Human origins is a subject of global interest. Not only are there questions of how, when, and where we evolved in the remote past but equally there are those which address the roots of our current ethnic diversity. All of these questions require fossil evidence to be answered. They need material collected from different habitats and samples from many countries. The fossil record has grown enormously in the past fifty years, and in particular with the wealth of finds made in the African Rift valley. It is to be hoped that a similar pace will follow, particularly in other parts of the Old World. We expect that the picture we have today will change enormously in the next fifty years. A brief prehistory of human evolution The course of human evolution can briefly be divided into four periods During this period the hominids split from the last common ancestor. On genetic and anatomical evidence this was a chimpanzee-like primate. Estimates of this divergence put the evolution of a distinct hominid line at 5 million years ago. The early evolution is exclusively African, and most of it south of the Sahara. In the last fifty years many fossil discoveries have revealed a complex picture of contemporary but very different hominids. For example, two million years ago in parts of this region the Australopithecines (southern apes) lived in the same habitats as early examples of our genus Homo. This co-presence of similar but unrelated lineages has been a consistent feature, until the present day, of human evolution. At some time between 2 and 1 million hominids moved north and colonized large parts of Asia and Europe. During this period there are only representatives of the genus Homo. However, there is considerable regional diversity, as shown by the shape of fossil skulls and teeth. These hominids were still confined to parts of the Old World. They were powerfully built and recent finds have shown them to be much larger than previously thought. For much of this period we see the regional evolution of Homo. The best known and largest sample comes from Europe and western Asia, where the Neanderthals form one of the best known fossil populations. As early as 150,000 years ago in eastern Africa we find fossil skulls of essentially modern type. Africa has now been identified both genetically and anatomically as the evolutionary centre for the appearance of people who looked, and eventually acted, like us. The most economical explanation of the evidence is that successive population movements out of Africa replaced the regional populations, such as the Neanderthals, in all parts of the inhabited Old World. One of the novelties associated with these modern people is their global colonization. It is in the last third of this period that people first colonized Australia, the Pacific islands, the northern parts of Asia, the American continents, and the Arctic. This great prehistoric colonization achieved primarily by people with a hunting and gathering lifestyle drew the demographic and geographical map for the later development of ethnic and regional populations of Homo sapiens.
5 million years to 1 million years ago.
1 million to 300,000 years ago.
300,000 to 30,000 years ago.
150,000 - 10,000 years ago.
5 million years to 1 million years ago
1 million to 300,000 years ago
300,000 to 30,000 years ago
150,000 - 10,000 years ago
Human origins is a subject of global interest. Not only are there questions of how, when, and where we evolved in the remote past but equally there are those which address the roots of our current ethnic diversity. All of these questions require fossil evidence to be answered. They need material collected from different habitats and samples from many countries. The fossil record has grown enormously in the past fifty years, and in particular with the wealth of finds made in the African Rift valley. It is to be hoped that a similar pace will follow, particularly in other parts of the Old World. We expect that the picture we have today will change enormously in the next fifty years.
A brief prehistory of human evolution
The course of human evolution can briefly be divided into four periods
During this period the hominids split from the last common ancestor. On genetic and anatomical evidence this was a chimpanzee-like primate. Estimates of this divergence put the evolution of a distinct hominid line at 5 million years ago.
The early evolution is exclusively African, and most of it south of the Sahara. In the last fifty years many fossil discoveries have revealed a complex picture of contemporary but very different hominids. For example, two million years ago in parts of this region the Australopithecines (southern apes) lived in the same habitats as early examples of our genus Homo. This co-presence of similar but unrelated lineages has been a consistent feature, until the present day, of human evolution.
At some time between 2 and 1 million hominids moved north and colonized large parts of Asia and Europe.
During this period there are only representatives of the genus Homo. However, there is considerable regional diversity, as shown by the shape of fossil skulls and teeth. These hominids were still confined to parts of the Old World. They were powerfully built and recent finds have shown them to be much larger than previously thought.
For much of this period we see the regional evolution of Homo. The best known and largest sample comes from Europe and western Asia, where the Neanderthals form one of the best known fossil populations.
As early as 150,000 years ago in eastern Africa we find fossil skulls of essentially modern type. Africa has now been identified both genetically and anatomically as the evolutionary centre for the appearance of people who looked, and eventually acted, like us. The most economical explanation of the evidence is that successive population movements out of Africa replaced the regional populations, such as the Neanderthals, in all parts of the inhabited Old World. One of the novelties associated with these modern people is their global colonization. It is in the last third of this period that people first colonized Australia, the Pacific islands, the northern parts of Asia, the American continents, and the Arctic. This great prehistoric colonization achieved primarily by people with a hunting and gathering lifestyle drew the demographic and geographical map for the later development of ethnic and regional populations of Homo sapiens.
Criteria for selection of hominid sites for inscription
In the light of the current general picture of human and hominid evolution we identify the following six criteria for assessing known sites:
- There is no substitute for good chronologies. Many of the arguments in palaeoanthropology stem from poor dating of fossils. Well dated material allows the taxonomist to sort out phylogenetic relationships and rates of evolutionary change. Dating by isotopic decay methods have revolutionized the subject
- The numbers of fossils from a single locality or within an identifiable geological unit. If well dated, the opportunities for scientific analysis of more than one skull or skeleton are very rewarding. The advantage of large samples lies in tackling questions of population variability, the necessary condition if evolution under natural selection is to occur
- The antiquity of the finds, is also dependent on good dating, preferably by science-based methods. While age is not a sufficient criterion by itself, it must be recognized that finds from certain periods (eg the crucial period 5-4 million years ago when hominids were splitting from the last common ancestor) are still extremely rare
- The potential for further finds must also be recognized. Preservation conditions can be assessed and ranked from poor to exceptional. However, there will always be an element of good fortune in finding fragmentary fossil material. Hominids were never very plentiful and their remains are hard to find. For example, the find of two teeth and a tibia at Boxgrove (southern England) increases in significance because of the preservation of 20km of similar deposits along an ancient shoreline.
- To talk of Hominid sites is increasingly a misnomer. Instead we should think of groups of closely related sites and even landscapes. What is needed in the study of human evolution are good contexts which preserve good environmental and archaeological evidence as well as hominid fossils. This is needed in order to interpret their lifestyles and capabilities.
- A number of fossils have an important historical and even iconic position in the discovery and demonstration of human evolution. These sites, such as Olduvai Gorge and La Chapelle aux Saints, are signposts on the route to our own self-discovery of our evolutionary heritage.
With these points in mind we have drawn up the following provisional list. We have organized the sites into three groups and indicated to which time period (A-D) they belong.
Group 1 Sites with hominid material that are already inscribed on the list Ngorongoro with Olduvai Gorge (Tanzania) A, B Zhoukoudian (China) B, D Awash and Omo Basins (Ethiopia) A, D Willandra Lakes (Australia) D Sangiran (Indonesia) A?, B
Group 2 Sites with hominid remains that score most highly on our six criteria and which we would recommend for consideration
Koobi Fora & Turkana Basin (Kenya) A,C,D Atapuerca (Spain) B Mount Carmel (Israel) C, D Sterkfontein Valley (South Africa) A Hadar/Afar (Ethiopia) A Fossil caves of the Dordogne (France) C, D
Group 3 Sites with important hominid remains for which a good case could be made but which do not score as highly
Eastern Germany travertine sites B, C Dolni Vestonice-Pavlov (Czech Republic) D Murray River cemeteries (Australia) D Solo River (Indonesia) B, C Raised beaches of Sussex (United Kingdom) B
Group 4 Sites with notable fossil material but the lowest scores on the six criteria.
* denotes no fossil hominid finds as yet but with every expectation of discovery.
Shanidar (Iraq) C Klasies River Mouth (South Africa) D *Schöningen (Germany) B Gibraltar (United Kingdom) C, D Monte Circeo (Italy) C, D Grimaldi (Italy) D Elandsfontein (South Africa) B Crimean caves (Ukraine) C, D Kostenki (Russia) D Vogelherd Cave (Germany) D Caune Arago (France) B Croatian caves C, D Haua Fteah (Libya) C, D Niah Caves (Malaysia) D Border Cave (South Africa) D
Recommended general reading
Day, M. H., 1986. Guide to fossil man, 4th edition. London, UK: Cassell.
Gamble, C. S., 1993. Timewalkers: the prehistory of global colonization. Stroud, UK: Alan Sutton.
Oakley, K. P., B.G. Campbell, and T.I. Molleson, 1971. Catalogue of fossil hominids. Part II Europe. London, UK: British Museum (Natural History).
Oakley, K. P., B.G. Campbell, and T.I. Molleson, 1975. Catalogue of fossil hominids. Part III Americas, Asia, Australasia. London, UK: British Museum (Natural History).
Stringer, C., and C. Gamble, 1993. In search of the Neanderthals: solving the puzzle of human origins. London, UK, and New York, USA: Thames and Hudson.
Stringer, C., and E. McKie, 1996. African exodus. London, UK: Cape.
Tattersall, I., 1995. The last Neanderthal: the rise, success, and mysterious extinction of our closest human relatives. New York, USA: Macmillan.
Professor Clive Gamble
University of Southampton,
Professor Chris Stringer
Natural History Museum, London,
14 October 1997
Context for World Heritage Bridges
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A joint publication with TICCIH, 1996
Bridging rivers, gorges, narrows, straits, and valleys always has played an important role in the history of human settlement. Since ancient times, bridges have been the most visible testimony of the noble craft of engineers. A bridge can be defined in many ways, but Andrea Palladio, the great 16th century Italian architect and engineer, hit on the essence of bridge building when he said "...bridges should befit the spirit of the community by exhibiting commodiousness, firmness, and delight." In more practical terms, he went on to explain that the way to avoid having the bridge carried away by the violence of water was to make the bridge without fixing any posts in the water. Since the beginning of time, the goal of bridge builders has been to create as wide a span as possible which is commodious, firm, and occasionally delightful. Spanning greater distances is a distinct measure of engineering prowess.
In terms of engineering, bridges are discussed by design or type (beam, arch, truss, cantilever, suspension, or moveable); length (usually expressed in terms of clear or overall span); and materials (stone, wood, cast and wrought iron, and what we use today - concrete and steel). The purpose of this contextual essay is to provide parameters of value and significance so that we can focus our attention on those bridges - globally - that best illustrate the history of bridge building, and to encourage their preservation.
What is a World Heritage bridge? The World Heritage Committee states that to be of World Heritage status a monument or site must be of outstanding universal value. It must illustrate or interpret the heritage of the world in terms of engineering, technology, transportation, communication, industry, history, or culture. World Heritage industrial sites and monuments must meet one or more of the following criteria and pass the test of authenticity:
Represent a masterpiece of human creative genius;
Have exerted great influence, over a span of time or within a cultural area of the world, on developments in engineering theory, technology, construction, transportation, and communication;
Be an outstanding example of a type which illustrates a significant stage in bridge engineering or technological developments.
A World Heritage bridge, like other properties, must meet the test of authenticity in design, materials, workmanship, or setting (the Committee has stressed that reconstruction is only acceptable if carried out on the basis of complete and detailed documentation of the original artefact and to no extent on conjecture). The criteria of authenticity may apply to Japanese bridges like the Kintaikyo spanning the Nishiki River in Iwakuni or Palladio's bridge over the River Brenta at Bassano a Grappa near Venice (Italy). In the same context, some bridges have been moved when unable to function at their original location. It is not unusual in the USA, for example, to relocate a metal truss bridge to a less travelled road when it can no longer handle the traffic; the same probably holds true for other countries. This is within the functional tradition of some bridge types and should not be viewed as a negative factor in determining the integrity of a relocated structure.
The definition of authenticity is in the process of being expanded to include intangible values such as a bridge that embodies the spirit or character of a people or place, as New York City is embodied in the Brooklyn Bridge, San Francisco in the Golden Gate, London in Tower Bridge, Sydney (Australia) in the Harbour Bridge, or Bosnia-Herzegovina in the recently destroyed Stari Most in Mostar.
Bridges nominated for World Heritage listing also must have legal protection and management mechanisms to ensure their conservation. The existence of protective legislation at the national, provincial, or municipal level is therefore essential and must be clearly stated in the nomination. Guidelines for nominations state that each property should be compared with properties of the same type dating from the same period, both within and outside the nominating State Party's borders.
For the purpose of this contextual essay, bridge design and construction is dealt with chronologically by material and by type. In addition to the obvious evaluation factors as age, rarity, integrity, and the fame of the builder, consideration also is given to the substructure (piers, abutments, foundation), the superstructure (beam, arch, truss, suspension, and combinations thereof), the materials of construction (their strength and properties), the evolution of construction techniques, and whether the bridge advanced structural theory or methods of evaluating material behaviour.
Bridges discussed in this essay illustrate important types or technological turning points and are listed at the end. Some, like the Pont du Gard (France) and the Iron Bridge (UK), are already inscribed on the World Heritage List. Others may be candidates for listing given adequate study, comparison, and evaluation. Not every potential World Heritage bridge candidate is cited. It is the job of TICCIH and its member countries to identify and make a case for outstanding bridges so they can be appreciated and protected like the great architectural and natural monuments already designated.
The first bridges were natural, such as the huge rock arch that spans the Ardèche in France, or Natural Bridge in Virginia (USA). The first man-made bridges were tree trunks laid across streams in girder fashion, flat stones, such as the clapper bridges of Dartmoor in Devon (UK), or festoons of vegetation, twisted or braided and hung in suspension. These three types - beam, arch, and suspension - have been known and built since ancient times and are the origins from which engineers and builders derived various combinations such as the truss, cantilever, cable-stayed, tied-arch, and moveable spans.
The essential difference among types is the way they bear their own weight - the "dead load" and the "live load" - a person, the railway train, wind, or snow that is applied to the bridge. The weight of beam, truss, and girder bridges bears directly downwards from their ends on the ground, piers, or abutments. Arch bridges thrust outwards as well as downwards, acting in compression. The cables of suspension bridges act in tension, pulling inwards against their anchorages.
If two or more beam or girder spans are joined together over piers, they become continuous, a form favoured by European engineers, who had the mathematical knowledge to analyse the indeterminate stresses introduced by such systems. A case in point is the Town lattice truss invented by Ithiel Town, an American, in 1820, which is a rare instance of reverse techno- logical transfer. The form originated in the USA, but was widely adopted in Europe, especially in iron railway bridges. The lattice fell into disfavour in the USA, where a preference existed for statically determinate bridges of heavy timber, whose forces were easier to calculate.
A more complex form of the beam is the truss, a rigid self- supporting system of triangles transferring both dead and live loads to the abutments or piers. A more complex form of the girder is the cantilever, where trussed and anchored ends of the girder support a central span. They were favoured for deep gorges or wide fast-flowing streams where false work, a temporary structure, usually of timber, erected to assist in the construc- tion of the permanent bridge, is impossible to build. The three principal types - beam, arch, and suspension - often were combined in a variety of ways to form composite structures, the type selected depending on the nature of the crossing, the span required, the materials at hand, and the type of load anticipated - pedestrian, vehicular, railroad, or a channel of water as in aqueducts.
Other than the clapper bridges of England and similar spans surviving in other countries, bridges dating from prehistoric periods are rare. Bridges of twisted vines and creepers found in India, Africa, and South America, the ancient cantilevers of China, Kashmir, and Japan, if any survive, or the wooden arches of Japan may be candidates for World Heritage listing because they perpetuate primitive ingenuity and craft technology that is important to recognize. Since some of their materials cannot be original, these structures will have to pass the test of authenticity.
In 51 BC, during the Gallic War, Caesar attested to the construction of narrow wooden bridges by Gallic builders over wide rivers as the Loire, Seine, and Allier of 600ft (200m) span, used by pedestrians and domestic animals. The stone vault probably first sprang forth in Anatolia and the Aegean region of Asia Minor (central and western Turkey) in the 2nd millennium BC for short spans in civic construction. The Mesopotamian civilizations introduced the first major development of brick vaulting in the royal palaces, and also probably the first important arch bridges in the 6th century BC.
Figure 1 Ponte Saint-Martin (c 25 BC) near Torino (Italy). Shunsuke Baba, photographer
The greatest bridge builders of antiquity were the Romans. They applied a civil engineering repertoire on an unprecedented grand scale and achieved impressive results. Roman engineering introduced four significant developments to the art of bridge building that never had been prominent before: the discovery and extensive use of natural cement, development of the coffer dam, perfection and widespread application of the semi-circular masonry arch, and the concept of public works (Figure 1).
In these important respects, the Roman engineer vastly improved upon the efforts of his predecessors. Public water supply was the most significant aspect of Roman civil engineering: nothing like it had been achieved before nor was it to be emulated until the 19th century. Structural evolution achieved by Roman engineers is manifest in aqueducts, dam construction, and highway bridges that relied on the development of concrete, and a growing awareness of its strength.
The Romans mixed a cement, pozzolana, found near the Italian town of Pozzuoli (ancient Puteoli), with lime, sand, and water to form a mortar that did not disintegrate when exposed to water. It was used as a binder in piers and arch spandrels, and mass-formed in foundations. Coffer dams (temporary enclosures built in river beds to keep the water out while the foundations were established) were made by driving timber piles into the river bed, removing water from the area enclosed, and then excavating the soft ground inside. Despite the use of coffer dams, Roman bridge foundations typically were not deep enough to provide sufficient protection against scour. Most of the Roman bridges that survive are those built on solid rock such as the Pont du Gard aqueduct (c AD 14) near Nîmes (France), the Alcantara Bridge (AD 98) on the Spanish-Portuguese border, and the aqueduct at Segovia (AD 98), which are three of the most famous surviving Roman bridges and aqueducts. Scholars have researched Roman bridges and aqueducts for many years, so it should be possible to arrive at a well reasoned selection of Roman-built bridges for World Heritage listing.
Bridges of Asia
Figure 2 Phra Phutthos (12th century), Kompong Kdei vicinity (Cambodia), was constructed at the end of the 12th century during the reign of Jayavarman VII. With more than twenty narrow arches spanning 246ft (75m), this is the longest corbeled stone-arch bridge in the world. Institute of Asian Culture, Sophia University, Tokyo, Japan
Bridge building in Asia extends back earlier in time than in Europe. Because structural concepts of suspension, cantilever, and arch were first developed there with great sophistication, every effort should be made to identify surviving examples (Figure 2). China was the origin of many bridge forms: Marco Polo told of 12,000 bridges built of wood, stone, and iron near the ancient city of Kin-sai. The first chain-link suspension bridge, the Panhogiao or Panho Bridge (c206 BC), was built by General Panceng during the Han Dynasty. In 1665, a missionary named Kircher described another chain-link suspension bridge of 200ft (61m) made up of twenty iron links, a common bridge type built during the Ming Dynasty that was not adapted until the 19th century in America and Europe. China's oldest surviving bridge, and the world's oldest open-spandrel segmental arch, is the Zhaozhou Bridge (c AD 605), attributed to Li Chun and built south-west of Beijing in Hebei Province during the Song Dynasty. Its thin, curved stone slabs were joined with iron dovetails so that the arch could yield without collapsing. This technique allowed the bridge to adjust to the rise and fall of abutments bearing on spongy, plastic soils and the live loads of traffic.
Following the decline of the Roman Empire with its many engineer- ing achievements, beam, arch, suspension, and cantilever bridge building flourished in China while languishing in Europe for nearly eight centuries. Chinese bridge builders experimented with forms and materials, perfecting their techniques. Selected examples, found in the countryside and parks, may be candidates for World Heritage listing.
Other fine bridges survive in Iran, such as the Bridge of Khaju at Isfahan (1667), with eighteen pointed arches, carrying an 85ft (26m) wide roadway with walled, shaded passageways, flanked by pavilions and watch towers. This magnificent bridge, combining architecture and engineering in splendid functional harmony, also served as a dam, and included a hostelry where travellers found cool rooms for rest and refreshment after hot desert crossings (Figure 3).
Picturesque bridges, such as the Kintaikyo at Iwakuni (1673), with its five wooden arches intricately wedged, slotted, and dovetailed together, are found in Japan. The superstructure of this bridge has been rebuilt for centuries (the central three arches every 18- 22 years, and the side spans every 36 years), maintaining the fine craft tradition of the bridge keepers for centuries (Figure 4). Shogun's Bridge (1638), crossing the Daiya-gawa River in the sacred City of Nikko, is the oldest known cantilever. The bridge was badly damaged in the typhoon of 1902, rebuilt, and exists today bearing foot traffic. It consists of hewn stone piers pierced with rectangular holes that permit the insertion of tightly fitting cut-stone struts, two anchor spans, timber beams jutting out in cantilever form, and a suspended span.
Figure 3 Bridge of Khaju (1667), Isfahan (Iran), combining architecture and engineering in splendid harmony, functioned as a bridge, dam, and a resort for thirsty travellers coming off the desert.
Shunsuke Baba, photographer
Figure 4 Kintaiko (1673), Iwakuni (Japan), with its five wooden arches intricately wedged, slotted, and dovetailed, has been faithfully rebuilt for centuries. Each generation of craftsmen has carefully replicated the joinery techniques and materials of their predecessors.Shunsuke Baba, photographer
The revival of bridge building in Europe following the fall of the Roman Empire was marked by the spread of the pointed arch westward from its origins in the Middle East. The pointed arch typically was a Gothic architectural form important structurally in the development of palaces, castles, and especially the cathedrals of western Europe, but not very important for bridges. Medieval bridges continued such multi-functional traditions as the Isfahan Bridge in Iran. Chapels, shops, tollhouses, and towers adorned fortified bridges such the 1355 Pont Valentré at Cahors (France) or the Monnow Bridge (1272, 1296) at Monmouth, Wales (UK), which were built with defensive ramparts, firing slits, and drawspans.
Christian religious orders formed after the fall of the Roman Empire greatly assisted travellers by building bridges. In western and central Europe, religious groups managed popular financial institutions, with Papal sanction, both for bridge construction and for hospitals. The influence of these groups lasted from the end of the 12th to the early 14th century, and their perseverance ensured the construction of major bridges over wide rivers as the Rhône and the Danube.
The bridge over the Rhône at Avignon (1187), for example, a wooden deck on stone piers, was built by such an order under the inspired vision of a young shepherd, later canonized as St Bénézet for his accomplishment. The four surviving arches, dating from the bridge's rebuilding around 1350, rank as one of the most remarkable monuments of medieval times in view of the 101-110ft (31-34m) elliptical arches with radii varying at the crown and haunches.
As the Middle Ages drew to a close, stone arches of remarkable spans were built in mountain valleys where rock abutments provided solid foundations for spans in excess of 150ft (50m), such as the Vieille-Brioude and the Grand Pont du Doux in France.
Renaissance and Neo-Classical bridges
The great era of medieval bridge building was followed by the Quattrocento, the transition period from the medieval period to the Italian Renaissance, when the confidence and unbounded enterprise of engineers was manifested in bridges like the 1345 Ponte Vecchio, an early Florentine bridge in Italy, designed by Taddeo Gaddi, that carries a street of goldsmiths' shops on three segmental arches. This was followed by the technical efficiency and artistic advancement of Renaissance ideals of civic order during the Neo-Classical period of the 17th and 18th centuries, represented by long span and multiple stone arches: eg Santa Trinità (1569) in Florence, the Rialto (1591) in Venice, and the Pont Neuf (1607) in Paris. These bridges, which are among the most famous bridges in the world today, are all on the World Heritage List, although only as components of historic town centre inscriptions. Renaissance engineers had learned much about foundations since Roman times, though they rarely were able to excavate deeply enough to reach hard strata. They had, however, perfected techniques of spread footings - wide timber grillages resting on piles driven into the river bed upon which stone piers were laid. In the foundation of the Rialto Bridge, designer Antonio da Ponte drove six thousand timber piles, capped by three stepped grillages so that the abutment stones could be laid perpendicular to the thrust lines of the arch. Though built on soft alluvial soils, the bridge continues to support a street of jewellery shops enjoyed by tourists four centuries later.
The end of the Italian Renaissance witnessed a new vision of bridge construction. More than merely utilitarian, bridges were designed as elegant, grand passage-ways that were part of the visual perspective of the idealized cityscape - major accents to the totally redesigned merchant and capital cities. No country attempted to advance this concept more than France at the end of the 16th century, where a national transportation department of architects and engineers was set up, responsible for designing bridges and roads (Ponts et Chaussées). This corps of specialists gave the Neo-Classical period a range of monumental and elegant bridges on rivers as the Loire (Blois, Orléans, Saumur) and the Seine in Paris. This model spread all over Europe, producing large monumental urban bridges in capitals such as London, Saint Petersburg, and Prague.
In Italy, Bartolomeo Ammannati evolved a new form for the Santa Trinità Bridge - a peculiar double-curved arch whose departure from an ellipse was deliberately concealed by a decorative escutcheon at the crown. Its 1:7 rise-to-span ratio resulted in an elegantly shallow, long-arch span widely adapted in other bridges of the Renaissance. The bridge was reconstructed using original stones recovered from the river following demolition during World War II.
By the mid-18th century, masonry bridge building had reached its apogee. French engineer Jean-Rodolphe Perronet designed and built the Pont de Neuilly (1774), the Pont de Saint-Maxence (1785), and the Pont de la Concorde (1791), the latter completed when Perronet was eighty-three. Perronet's design goals were to slim down the piers and to stretch arches to the maximum. The Pont de la Concorde still represents the perfection of masonry arch construction, even though sceptical officials forced Perronet to shorten the unprecedented centre span of the bridge to 92ft (28m). Long, elegant, elliptical arches, piers half their former widths, special machinery for construction, and the introduction of an architectural motif used until the 1930s, the open parapet with turned balusters, completed this outstanding bridge. Widened in the 1950s, its original appearance was carefully maintained. Another masterpiece of the French Classical style is the Pont de Bordeaux of nineteen arches, more than 1640ft (500m), completed in 1822.
Figure 5 Pontypridd Bridge (1756) over the Taff in South Wales (UK), had to be rebuilt several times until its builder, William Edwards, got the correct rise-to-span ratio to ensure that the 140ft (43m) arch would not collapse after removal of the falsework.Shunsuke Baba, photographer
In the United Kingdom, a young Swiss engineer, Charles Labelye, was building the English equivalent of Perronet's bridges. On his first bridge, Westminster (1750) over the Thames, he developed the caisson, which made it possible for pier foundations to be built in deep, fast-flowing waters. To solve a problem that had confounded bridge builders since Roman times, Labelye used huge timber boxes constructed on shore, floated into position, and slowly sunk to the bottom of the river by the weight of the masonry piers being laid above. Fifteen semicircular arches, incrementally diminishing in length from the centre and rising in a graceful camber, set a high engineering and architectural standard that stood for over a hundred years.
England's other great bridge designer during this period, John Rennie, built the first Waterloo Bridge in 1811. Its level road and arches lasted until 1938. Rennie's next great bridge was Southwark Bridge (1819), also over the Thames in London, which was built not in stone but in the new miracle material of the 19th century - cast iron. It had three arches whose central span of 240ft (73m) dramatically demonstrated the potential of the new material.
Wooden bridges are some of the most ancient. The first Roman bridge, the Pons Sublicius (c 621 BC), was a wood-pile structure over the Tiber in Rome, extending pedestrian access to the Aventine Hill. The earliest detailed description of a wooden bridge, a timber-pile structure over the Rhine constructed in 55 BC, was written by Julius Caesar in his De Bello Gallico. The best extant model of this type survives today over the Brenta at Bassano a Grappa, near Venice. It was built by Palladio in 1561, destroyed in 1945, and reconstructed identical to the original in 1948.
By the mid-18th century, carpenters working in the forested regions of the world further developed the timber truss bridge. The most famous were two Swiss brothers, Johannes and Ulrich Grubenmann, who built bridges at Schaffhausen, Reichenau, and Wettingen that combined diagonal struts and trusses to produce remarkably long spans for their time. The Schaffhausen Bridge (1757), over the Rhine in northern Switzerland, had two spans, 171ft and 193ft (52m and 59m) respectively, which rested lightly on an intermediate pier when loaded. It was burned by the French in 1799 during the Napoleonic Wars. One of the few Grubenmann bridges to survive is Rumlangbrücke (1766), with a span of 89ft (27m).
Figure 6 Bridgeport Bridge (1862), clear-spanning 208ft (63m) over the South Fork of the Yuba River near Grass Valley, California (USA), has two parallel trusses based on the Howe patent of timber and iron rods, flanked by solid wooden arches cut to the curves and reflected in the exterior siding. It is the second longest covered wooden bridge span in the USA, after the Blenheim Bridge (1855) in New York State, which is 210ft (64m). Jet Lowe, HAER Collection
European engineers visiting the New World during the 19th century marvelled at the spans achieved by American timber bridges. Especially noteworthy was Louis Wernwag's 340ft (104m) arch truss of 1812, the "Colossus," over the Schuylkill in Philadelphia, the longest spanning bridge in the world at the time. Covered bridges, sheathed in wood to keep the structural timbers from deteriorating, are an icon of the American landscape. Outstanding spans that survive today include the Cornish-Windsor Bridge (1866) over the Connecticut River and the Bridgeport Bridge (1862), whose clear span of 208ft (63m) makes this gateway to the California goldfields the second longest single span. According to the National Society for the Preservation of Covered Bridges Inc, some 800 wooden covered bridges survive in the USA, more than in any other country (Figure 6).
Regardless of the capability of advanced societies like the Romans to build bridges in stone, the material for the ages, its cost always remained a problem. Wooden bridges were an economic alternative important to every civilization during all historic periods from prehistoric times to the first American settlement, from classical Rome to the European Enlightenment, including China, Japan, and south-east Asia. Wooden bridges have played a major role in the history of human development. The architectural varieties and structural types - girder, arch, suspension, truss, pontoon, and covered - were numerous. By virtue of the nature of their material, extant examples are scarce, as is the historic record. Nature, acts of God, war, and arson have decimated wooden bridges throughout time. A special global effort should be initiated to identify, access, and protect wooden structures of all kinds. A group of experts should be convened in the USA and in other parts of the world where timber bridges survive to recommend a selection for nomination to the World Heritage List.
Theoretical advances during the Renaissance and Neo-Classical period
Thanks to Galileo, Renaissance mathematicians and scientists understood beam action and the theory of framed structures. The truss, used by the Romans as stiffening on the Rhine bridge (55 BC) and in roof structures, was refined by the Italian architect- engineer Andrea Palladio. His classic treatise on Greek and Roman architecture, I Quattro Libri dell'Architettura, was published in 1570, and was widely distributed after translation into English by Isaac Ware in 1755. It contained the first drawings of a truss, the simplest and most easily visualized form for transferring both dead and live loads to piers and abutments, accomplished by a rigid self-supporting system of triangles. Palladio built several truss bridges, the most important being the Bassano Bridge (1561) over the River Brenta in the Veneto region in northern Italy. Destroyed several times, it has been carefully rebuilt faithfully following the original layout and exists today as the only example of one of Palladio's bridges.
The truss form, derived from the Romans, represents one of the Renaissance's most significant contributions to bridge building. Renaissance engineers also devised daring innovation in arch forms - the segmental, elliptical, and multi-centred.
The Hungarian, Janos Veranscics, reviewed these and other achievements in the structural arts at the end of the Renaissance in Machinae Novae, published in 1617. Several concepts that later became standard bridge practice first were illustrated in this volume: the tied arch, the Pauli or lenticular truss (in wood), the all-metal truss (in cast brass), a portable, metal chain-link suspension bridge, the use of metal in reinforcing wooden bridges, and the eye-bar tension member (again in brass).
In 1716, Henri Gautier published Traité des Ponts, the first treatise devoted entirely to bridge building, during the Age of Reason when empirical bridge design gave way to rationalism and scientific analysis. The book became a standard work of reference throughout the 18th century. It covered both timber and masonry bridges, their foundations, piers, and centring.
A far-sighted policy that led to the first national department of transportation in France was started by Henri IV and Sully at the end of the 16th century. During the second half of the 17th century, it was reorganized by Colbert as the Corps des Ingénieurs des Ponts et Chaussées, a group of state architects and engineers, during the reign of Louis XIV. In 1747, the École des Ponts et Chaussées, the oldest academic institution in the world for civil engineering education in the design of roads and bridges, was started, with Perronet as its first director. The first theoretical studies concerning the stability of arches, transmission of forces, and the multi-radius form were conducted at the school by La Hire, Gautier, Bélidor, Coulomb, and Méry.
Though extremely versatile, wood has one obvious disadvantage - it burns. Wernwag's Colossus, destroyed by fire in 1838, is but one example of many outstanding wooden bridges lost in this manner throughout history. There was another material, however, whose use at the end of the 18th century offered bridge engineers an alternative to the traditional materials of timber, stone, and brick. Although it had first been used in antiquity, iron was the miracle material of the Industrial Revolution. The Greeks and Romans had used it to reinforce stone pediments and columns in their temples and iron links had been forged by the Chinese and used in suspension bridges.
The successful smelting of iron with coke, rather than charcoal, by English ironmaster Abraham Darby in 1709 freed iron production from fuel shortage restrictions, made large castings possible, and facilitated creation of the arch ribs for the world's first iron bridge, built seventy years later. In 1754, Henry Cort of Southampton (England) built the first rolling mill, making possible the efficient shaping of bar iron; in 1784 he patented a puddling furnace by means of which the carbon content in cast iron could be reduced to produce malleable iron. These two milestones of metallurgy realized the potential of iron as a major building material. Bridges were one of the first structural uses of iron, preceded only by columns (not yet beams) to support the floors of textile mills.
Figure 7 Dunlaps Creek Bridge (1839), Brownsville, Pennsylvania (USA), spans 80ft (24m) on five elliptical ribs of cast iron made of nine 14ft (4m) segments flanged at the ends and bolted. The triangular bracing in the spandrels is reminiscent of Telford's iron bridges in Shropshire (UK), and the tubes resemble the eliptical arches of the Pont du Carrousel, built over the Seine in Paris in 1834. Library of Congress
The first successful all-iron bridge in the world was designed by Thomas Farnolls Pritchard, an architect who suggested using the material as early as 1773. Built by two ironmasters, Abraham Darby and John Wilkinson, to demonstrate the versatility of cast iron, the bridge spans 100ft (30m) over the River Severn at Coalbrookdale (UK), on five semi-circular ribs of cast iron. The Iron Bridge was followed by a succession of cast-iron arches built throughout Europe. Few cast-iron arch bridges were built in the USA as the iron truss, derived from wooden forms, was preferred. One iron arch, however, merits mention, as it is the oldest iron bridge in America. Dunlaps Creek Bridge (1839), designed by Captain Richard Delafield of the Army Corps of Engineers for the National Road in Brownsville, Pennsylvania, survives to this day, still carrying traffic (Figure 7). Because the material could be moulded into elaborate shapes, extravagantly decorative iron arches were used for pedestrian bridges on the grounds of estates and imperial palaces, such as Catherine the Great's Tsarskoye Selo in St Petersburg (Russia), or urban pleasure grounds, such as Central Park in New York City (USA). Both places have remarkable collections of cast-iron arch bridges.
Figure 8 Royal Albert Bridge, Saltash, Cornwall (UK), was the last great enterprise of Isambard Kingdom Brunel, England's foremost Victorian engineer. This photograph served as the frontispiece to William Humber's A Complete Treatise on Cast and Wrought Iron Bridge Construction, published in 1864, and shows one of the great lenticular spans being jacked into place. It was 445ft (135m) long, consisting of a single wrought-iron elliptical tube upper chord and a curved bottom chord of linked eyebar chains connected by open truss bracing. The trusses were fabricated on shore, then floated into position and jacked into position over the Tamar. Institution of Civil Engineers, London
Engineers in the 19th century improved the technology of sinking foundations to bedrock. Up until that time, coffer dams and crude caissons were the only means by which foundations could be constructed in water. Their use was limited by the length of wooden piles and by soils that were unsuitable for pile driving because they were either too soft or too hard. Credit for developing the first pneumatic caisson belongs to William Cubitt and John Wright, who used the technique on the bridge (1851) over the River Medway at Rochester (UK). It was similar to the caisson developed by Labelye, but differed in that the chamber resting on the river's bottom was airtight and required workmen to enter by means of airlocks after the water had been driven out by pneumatic pressure. Working in this environment, men suffered from the little understood "caissons disease," now better known as "the bends." The eventual diagnosis of this condition permitted the construction of bridges of unprecedented scale, overcoming the impediment of deep, broad rivers. Isambard Kingdom Brunel used the technique for sinking the piers of his bridge at Chepstow, Wales (UK) and, on a much grander scale, on the Royal Albert Bridge (1859) over the Tamar at Saltash in Cornwall (Figure 8). Here, the central pier was built on a wrought-iron caisson 37ft (11m) in diameter, sunk to bedrock in 70ft (21m) of water and 16ft (5m) of mud.
Another improvement in foundations in the early 19th century involved hydraulic cement. A better scientific understanding of the material by the Frenchman Vicat and the Englishman Aspdin and discovery of the material in a natural state in 1796 on the Isle of Sheppey in the Thames estuary, by Lafarge at Le Teil (France), and by Canvass White on the Erie Canal in New York in 1818, led to its use in sinking foundations by the new method of direct flow into coffer dams underwater, as at the suspension bridge at Tournon (France) in 1824. Hydraulic cement had the amazing ability to set under water, and was consequently used in aqueducts, piers and abutments, culverts, and locks.
Following the construction of the Iron Bridge at Coalbrookdale, Thomas Telford, a gifted, self-educated Scottish engineer, built a number of cast-iron arches throughout the British Isles. These included canal aqueducts, which were extraordinarily innovative arrangements in which the cast iron had real structural value. On both the Longdon-on-Tern (1796) and the Pontcysyllte (1805) aqueducts, the cast-iron sections that formed the side walls of the trunk were wedge-shaped, behaving like the voussoirs of a stone-arch bridge and bolted through flanges. Telford's most ambitious notion, however, was his proposal of 1800 for a single cast-iron arch of 600ft (183m) span over the Thames to replace Old London Bridge. An earlier proposal was unveiled in France by Montpetit in 1779 for a bridge of 400ft (122m) over the Seine, thought to have been the inspiration for Telford's idea. Even the young United States got into the act when Thomas Paine, the political philosopher, proposed an iron arch of 400ft span over the Schuylkill in Philadelphia. But the next most outstanding achievement after Coalbrookdale was the cast-iron arch over the River Wear at Sunderland (UK), because it actually was built. Completed in 1796 by Thomas Wilson, the bridge had an unprecedented span of 236ft (75m).
Figure 9 Rio Cobre Bridge (1800), Spanish Town, Jamaica, the oldest iron bridge in the western hemisphere, was designed by Thomas Wilson and employs the same iron voussoir, incremental circular spandrel bracing, and cast-iron plate deck as the earlier Wearmouth Bridge. Essentially a "kit bridge," the system of small castings held together by wrought-iron ties, tubes, and bolts lent itself to export. Many bridges of this type were shipped to distant colonies of the British Empire Eric DeLony, photographer
Today, several collections of cast-iron arches survive in different countries, the largest being in the United Kingdom, six in the USA, a few in France and Spain, and a remarkable selection surviving in Russia, dating back to the reign of Catherine the Great. These need to be studied and a selection made for nomination.
By 1800, most European engineers were open to using cast iron. Architects, however, preferred traditional materials such as granite and marble for the visible parts of buildings and wood for hidden structural parts like roof trusses, and did not accept cast iron as having aesthetic merit or structural value. In the USA, still blessed with abundant virgin forests, the early 19th century was the era of "carpenter engineers." Men like Timothy Palmer, Lewis Wernwag, Theodore Burr, and Ithiel Town followed British custom by conceiving and building truss forms predicated on intuition and pragmatic rules of thumb. Their craft tradition of knowledge, passed down from master to apprentice, contrasted with the scientific analysis and mathematical formulas practised by French government engineers. Models were built and loaded to failure and broken members replaced with stronger ones until the model supported loadings equivalent to a real live load plus a safety factor.
Patents were granted in the USA for composite wood and iron bridges, transitional structures that capitalized on the availability of cheap timber. When the American iron industry caught up with Europe's by the mid-19th century, bridge building took the direction of composite pin-connected trusses, with sophisticated castings for joint blocks and compression members, and forged eyebars and wrought-iron rods for tension members, all fabricated to high tolerances. This allowed them to be assembled easily and inexpensively in the field by unskilled labour using simple tools and erection techniques. The system prevailed in the USA because that country lacked a skilled labour force, and the remoteness of many bridge sites hampered the use of sophisticated machinery or the shipping of large bridge parts over long distances. A spirited debate ensued between England and the former colony during the last quarter of the 19th century over which system was best: easily erected pin-connected trusses on the "American plan," or European-style riveted trusses. Even though the rigid riveted truss was of superior design, American bridges remained competitive in world bridge markets until the early 20th century because they were cheaper and swiftly erected.
Figure 10 Gauntless Viaduct (1825) is the only fragment of the original Stockton & Darlington Railway. Fortunately, the ironwork was preserved and featured during the centenary celebration of the world's first railway in 1825. It was later displayed at the former rail museum at York, as shown in this photograph. In 1975, when the museum became the new National Railway Museum, it was moved and erected at its original site in West Auckland (UK). Robert Vogel, Smithsonian Institution, photographer
For years, the distinction of being the world's oldest surviving iron railway bridge has been accorded by scholars to the Gaunless Viaduct (1825), on display at the National Railway Museum, York (UK) (Figure 10). Designed by George Stephenson for the first railway, the 37 miles (23km) between Stockton and Darlington in north-east England, it consists of four 12.5ft (4m) lenticular truss spans with curved top and bottom chord members of 2.5in (6cm) diameter wrought-iron rods and five vertical iron posts cast integrally with the wrought-iron chord members. In the last 20 years an older bridge has been discovered in South Wales (UK) at Merthyr Tydfil, a major early 19th century iron-producing centre. Pont-y-Cafnau (Bridge of Troughs) is a unique cast-iron combined aqueduct tramroad bridge below the confluence of the Taff and Taff Fechan, built in January-June 1793 by Watkin George, Chief Engineer of the Cyfarthfa Ironworks, to carry an edge railway and water channel. An iron trough-like girder is carried in an A-frame truss of cast iron spanning 47ft (14.2m), held together by mortise-and-tenon and dovetail joints. The next extant iron railway bridge seems to be another recently discovered at Aberdare (1811), followed by Gaunless. The oldest still in service is Hall's Station Bridge, a Howe truss designed in 1846 by Richard Osborne, a London-born Irishman who worked as engineer for the Philadelphia & Reading Railroad, although its current use is vehicular and not rail. The first major iron truss with pin connections was built in the USA in 1859, and the earliest iron cantilever in Germany in 1867, over the Main at Hassfurt.
Figure 11 Bollman Bridge (c 1869), Savage, Maryland (USA). This pre-restoration photograph shows the paired stanchions located at mid-span that support the anchorage block where the radiating suspension stays all meet in pinned connection. The octagonal profile of the vertical and horizontal compression members was a design motif of Wendel Bollman, the bridge's designer. He, along with Albert Fink, who designed a similar type of structure known as the Fink truss, motivated the chief engineer of the Baltimore & Ohio Railroad, Benjamin Henry Latrobe III, to use iron bridges exclusively for the system's major spans. William Barrett, HAER Collection
Another important composite iron truss surviving from the early period of iron bridge construction is the Bollman bridge (c 1869) at Savage, Maryland (USA) (Figure 11).
Britannia Bridge (1850) across the Menai Straits, Wales (UK), designed by Robert Stephenson and William Fairbairn, was the prototype of the plate-girder bridge, eventually used throughout the world. Originally intended to be a stiffened suspension bridge of four spans, each span (459ft (140m) over the channel; 230ft (70m) land spans) consisted of paired rectangular wrought- iron tubes through which the trains passed. Although Navier published his theory of elasticity in 1826, so little was known of structural theory that Stephenson relied primarily on empirical methods of testing, modifying, and retesting a series of models to design the tubes. They were fabricated on site, floated into position, and raised into place by hydraulic jacks. Riveting was done both by hand and using pneumatic riveting machines invented by Fairbairn. So strong were the tubes that the suspension chains were abandoned. The bridge continued in service until irreparably damaged by fire in May 1970, when the world lost one of its most remarkable 19th century engineering monuments was lost, but the near-contemporary Conway Castle Bridge (1848) survives.
Although the 19th century was marked by significant technological progress, such breathtaking achievement had its price. Three- quarters of the way through the century, two events, one on either side of the Atlantic, sobered the engineering profession. These took the form of accidents: the Ashtabula, Ohio, bridge disaster of 1876 in the USA, and the Tay Bridge disaster in Scotland (UK) in 1879. Forewarnings had occurred in Europe as early as 1847, when one of Robert Stephenson's composite cast and wrought-iron girder bridges over the River Dee on the Chester & Holyhead Railway collapsed. Three years later, 478 French soldiers were pitched into the Maine at Angers when one of the anchoring cables of a suspension bridge embedded in concrete tore loose during a storm, mainly owing to resonance oscillation and by the oxidation of the iron wires. The Dee Bridge disaster spurred the development of malleable wrought-iron girders, thought to be of safer construction. Collapse of the Basse-Chaine Bridge resulted in a twenty-year moratorium on cable-suspension bridge construction in continental Europe.
Scientific analysis of bridge design during the 19th century
It took the worst bridge disasters of the century in the USA, Great Britain, and France to usher in the development of standards, specifications, and enough regulation to protect the travelling public. The loss of 83 lives caused by the collapse of a cast- and wrought-iron truss in Ashtabula prompted an investigation by the American Society of Civil Engineers. The loss of 80 lives by failure of a section of the two-mile-long Tay Bridge resulted in similar inquiries in Britain.
The reasons for these major failures were similar: ignorance of metallurgy resulted in uneven manufacturing methods and defective castings, and inadequate inspection and maintenance were inherent at both bridges. For the Tay Bridge, exceptionally strong vibrations due to dynamic wind stresses under a moving load created a lack of aerostatic stability and eventual failure. It took engineers another quarter-century to perfect bridge design according to advanced theories of stress analysis, understanding of material properties, and renewed respect for the forces of nature. A definitive understanding of the physical oscillations and vibrations of structures did not occur until the middle of the 20th century after the Tacoma Bridge collapse in the USA in1940.
Advances in design theory, graphic statics, and a knowledge of the strength of materials by engineers such as Karl Culmann and Squire Whipple were achieved in the second half of the 19th century, but the factor that most influenced the scientific design of bridges was the railroads. Engineers had to know the precise amount of stresses in bridge members to accommodate the thundering impact of locomotives. Founded on the pioneering work of the American Squire Whipple and other European engineers as Collignon, the last quarter of the 19th century witnessed broad application of both analytical and graphical analysis, testing of full-size members, comprehensive stress tables, standardized structural sections, metallurgical analysis, precision manufacturing and fabrication in bridge shops, publication of industry-wide standards, plans, and specifications, inspections, and systematic cooperation between engineers, contractors, manufacturers, and workers. The combined experience of the railroads, bridge manufacturing companies, and the engineering communities enabled the railroads successfully to tackle long-span iron and steel bridges and long-span trussed-roof train sheds, two engineering icons of the 19th century.
Figure 12 Whipple Truss Bridge (1867), Normanskill Farm, Albany, New York (USA), remains in service to this day, restricting only buses and trucks, thus testifying to the efficacy of Whipple's design. All members are original, their sizes determined by the forces they carried, deduced from scientific analysis.Smithsonian Institution
The first practical design solution was obtained independently in the USA by Squire Whipple in 1847, and in Russia by D I Jourawski in 1850. Whipple had been working on the problem since before 1841, when he patented and built his all-iron bowstring truss bridge, which proved exceptionally suitable for short highway and canal spans. His book on stress analysis, A Work on Bridge Building, is recognized as the USA's contribution to structural mechanics for the period. His major breakthrough was the realization that truss members could be analysed as a system of forces in equilibrium, assuming that a joint is a frictionless pin. Forces are broken down into horizontal and vertical components whose sums are in equilibrium. Known as the "method of joints," it permits the determination of stresses in all members of a truss if two forces are known. Whipple clearly outlined methods, both analytical and graphical, for solving determinate trusses considering uniformly distributed dead loads and moving live loads. Over a dozen of Whipple's bowstring trusses survive as elegant illustrations of his breakthrough conclusions (Figure 12).
The next advance was the "method of sections" published in 1862 by A Ritter, a German engineer. Ritter simplified the calculations of forces by developing very simple formulae for determining the forces in the members intersected by a cross-section. The third advance was a better method of graphical analysis, developed independently by James Clerk Maxwell, Professor of Natural Philosophy at King's College, Cambridge (UK), published in 1864, and Karl Culmann, Professor at the newly established Federal Institute of Technology (Eidgenossische Technische Hochschule) in Zürich (Switzerland), who published his methods in 1866. The solution of bending in a cantilever was developed over a long period of time, starting with Galileo's famous illustration of the wooden beam, anchored in the ruinous masonry wall, holding a stone weight at its end. Although it was not entirely accurate, subsequent solutions were discussed in terms of Galileo's cantilever. C A Coulomb in France hypothesized in 1776 that the flexural stress in a cantilevered beam had a maximum value in compression on the bottom edge and a maximum value in tension on the top with a neutral axis somewhere between the two surfaces. The problem of understanding bending moments in mechanical terms was described by Louis Marie Henri Navier in his Résumé de leçons données à l'École des Ponts et Chaussées in 1826. The Swiss mathematician Leonard Euler provided the solution to the elastic buckling of columns as early as 1759.
Railroad viaducts and trestles
Railroads, the transportation mode that revolutionized the 19th century, generated a bridge type that merits special attention. The limited traction of locomotives forced the railroad engineer to design the line with easy gradients. Viaducts and trestles were the engineering solution for maintaining a nearly straight and horizontal line where the depth and width of the valley or gorge rendered embankments impracticable. These massive, elevated structures were first built in Roman style of multiple-stone arches and piers. Later, when wrought iron and steel became available, engineers built viaducts and trestles of great length and height on a series of truss spans or girders borne by individual framed towers composed of two or more bents braced together.
Figure 13 Thomas Viaduct (1835), Relay, Maryland (USA). This illustration from The United States Illustrated, published in the 1850s, shows the heroic proportions of this massive stone structure, constructed while the Baltimore & Ohio Railroad was still influenced by the British precedent of strong, durableconstruction.Smithsonian Institution
The Thomas Viaduct on the Baltimore & Ohio Railroad (1835) (Figure 13), the Canton on the Boston & Providence Railroad (1835), and the Starrucca on the New York & Erie Railroad (1848) are the oldest stone viaducts and three of the great monumental structures of the USA's early railways. Examples in Europe include the Viaduc de Barentine (1846), constructed by British navvies under the direction of MacKenzie and Thomas Brassey in brick rather than stone, and the Viaduc de Saint-Chamas (1847), both in France. In the United Kingdom, notable viaducts include the 181ft (55m) Ballochmyle Viaduct (1848), designed by John Miller for the Glasgow & South Western Railway, the largest masonry-arch span in the country; the Harrington Viaduct (1876), the longest at 3500ft (1067m), carried on 82 brick arches; the Meldon Viaduct (1874), the best surviving iron viaduct in Devon; and, in concrete, the Glenfinnian Viaduct (1898), which has 21 arches of mass-poured concrete.
Most notable of the early trestles was the Portage Viaduct in the USA (1852), a remarkable timber structure designed by Silas Seymour, carrying the Erie Railroad over the Genessee River, 234ft (71m) above the water and 876ft (276m) long (Figure 14). It was destroyed by fire in 1875, to be replaced in iron, and later in steel. One of the first iron viaducts was the 1673ft (510m) long Crumlin Viaduct (1857), constructed by Thomas W Kennard and designed by Charles Liddell for the Newport-Hereford line, 217ft (66m) above the Ebbw Vale in Wales (UK). It served as the prototype for later ones, such as the Viaduc de la Bouble (1871), a series of lattice girders on cast-iron towers flared at the bottom, built under the direction of Wilhelm Nordling. It was 1296ft (395m) long by 216ft (66m) high on the Commentry-Gannett line in France.
Figure 14 Portage Viaduct (1852) (USA), photographed shortly after it was completed for this stereoscopic view, was the wonder of visiting engineers, who used it frequently as an example of American timber bridge construction technology in European texts Eric DeLony, photographer
Figure 15 Kinzua Viaduct (1900), located on the Bradford Branch in a remote region near the town of Kushequa in north-west Pennsylvania (USA), was originally constriucted in 1882 by the New York & Erie Railroad to service lumber mills in this lush, forested corner of Pennsylvania. The present structure, 302ft (92m) high and 2052ft (625m) long, replaced the original when Erie officials decided that the bridge could no longer support their heavier trains. Today the viaduct forms the main attraction of a state park. Jack Boucher, HAER Collection
The first viaduct of iron in the USA was designed by Albert Fink for the Baltimore & Ohio Railroad over Tray Run in the Cheat River valley in (West) Virginia, a remote, wild, yet picturesque site in the wilderness. Dating from 1853, it was a series of inclined cast-iron columns resting on stone pedestals connected at the top by cast-iron arches, the whole system braced by wrought-iron ties. Examples surviving today in North America include the Kinzua Viaduct (1900) on the former Erie Railroad in Pennsylvania (Figure 15), and the Lethbridge Viaduct (1909) on the Canadian Pacific in Alberta, composed of alternating 67ft (20m) trestles and 100ft (30m) girders, at 5327ft (1624m) long the longest and heaviest in the world. The Tunkhannock Viaduct (1915), 240ft high (73m) by 2375ft long (724m), is the largest reinforced concrete-arch bridge in the world.
Although suspension bridges had been known in China as early as 206 BC, the first chain suspension bridge did not appear in Europe until 1741, when the 70ft (21m) span Winch Bridge was constructed over a chasm of the River Tees (UK), with the flooring laid directly on two chains. It was an American, James Finley, however, who built the first practical suspension bridge in 1796 in the USA. This was a bridge over Jacobs Creek near Uniontown, Pennsylvania, which Finley described as a "stiffened" bridge in an article he published in Portfolio in 1810. The span displayed all the essential elements of the modern suspension bridge: a level deck hung from a catenary system suspended over towers and anchored in the ground, and a truss-stiffened deck, resulting in a rigid bridge capable of supporting relatively heavy loads.
The world's first wire-cable suspension bridge was a 408ft (124m) temporary footbridge built in 1816 for the workers of wire manufacturers Josiah White and Erskine Hazard over the Schuylkill in Philadelphia. The USA contributed little more until the middle of the century, but these inventions were immediately followed up in Europe. The French and Swiss continued to use wire cables, developing methods of fabricating the cables in situ. In 1822, Marc Séguin proposed a suspension cable made up of one hundred thin iron wires, erected his first suspension bridge (actually a catwalk like the White and Hazard bridge) over the Cance at Annonay, and proposed a major structure over the Rhône at Tournon. By scientific testing, he proved the strength of the wire cable - twice that of the English iron eyebar chain - and described all in Des ponts en fil de fer, published in 1824. The world's first permanent wire-cable suspension bridge, designed by Séguin and Guillaume-Henri Dufour, was opened to the public in Geneva in 1823, followed by Séguin's Tain-Tournon Bridge, a double suspension span over the Rhône, completed in 1825. Its 1847 replacement still stands, probably the oldest wire-cable suspension bridge in the world, with its carefully replicated wooden stiffening truss and deck. Several of Séguin's first-generation wire-cable suspension bridges, dating from the 1830s, remain over the Rhône at Andance and Fourques, but the decks have been replaced with steel. Wire cable attained its place as the system par excellence for long-span bridges in 1834, with the 870ft (265m) Fribourg Bridge, designed by Joseph Chaley over the Sarine in Switzerland. From this developed the typical European standard - cables of parallel, thin wires, light decks stiffened by wooden trusses, piers and abutments sunk - using hydraulic cement - of which hundreds were built.
Figure 16 Menai Suspension Bridge (1826)(UK) sat on massive stone piers and viaduct approaches to gain the 50ft (15m) clearance required by the British Admiralty for the passage of ships. Shunsuke Baba, photographer
The British preferred to use chains of linked eyebars, and achieved spans of lightness and grace, all the more effective in contrast with the colossal masonry suspension towers. The United Kingdom's first large-scale suspension bridge was the Menai Bridge on the London to Holyhead road over the straits of the same name in North Wales (Figure 16). Travellers would board a ship at Holyhead for the final leg of the trip to Ireland. It was designed by Thomas Telford and completed in 1826, with an unprecedented span of 580ft (177m) using wrought-iron eyebars, each bar being carefully tested before being pinned together and lifted into place. The roadway was only 24ft (7m) wide and, without stiffening trusses, soon proved highly unstable in the wind. The Menai bridge was twice rebuilt before the entire suspension system was replicated in steel in 1940 and the arched openings in the towers were widened. The oldest suspension bridge extant today is the Union Bridge over the River Tweed at Berwick (UK), a chain-link bridge designed and erected by Captain Samuel Brown in 1820, with a span of 449ft (137m).
With the French declaring a moratorium on suspension-bridge construction following the collapse of the Basse-Chaine Bridge in 1850, the creative edge passed back across the Atlantic, to be picked up by Charles Ellet and John Augustus Roebling in the USA. After studying suspension bridges in France, Ellet returned with the technology and built a 1010ft (308m) bridge over the Ohio River at Wheeling, (West) Virginia, in 1849, which was the longest in the world. Thanks to techniques developed by the Roeblings and used in the structure's rebuilding, following a storm that ripped the cables off their saddles, the bridge remains in service today.
Figure 17 Niagara Bridge (USA), whose completion in 1855 vindicated John Roebling's conviction that the suspension bridge would work for railroads, lasted nearly half-a-century before it had to be replaced in 1896. At mid-century, it was the only form capable of uniting the 821ft (250m) gorge in a single span. This half-stereoscopic viewshows the massive stiffening trusses and the wire-cable stays that tied the deck superstructure to the walls of the gorge. Eric DeLony Collection
Roebling had arrived in the USA ten years earlier and established a wire-rope factory in Saxonburg, Pennsylvania, which he later moved to Trenton, New Jersey. Educated in Europe, he would have been exposed to the concepts of wire-cable suspension bridge engineering of the French and Swiss. He and Ellet competed for primacy in suspension bridge design. Roebling won out when he took over design of the Niagara Suspension Bridge from Ellet, successfully completing it in 1855 (Figure 17).
The inherent tendency of suspension bridges to sway and undulate in wavelike motions under repeated rhythmic loads such as marching soldiers or the wind was not completely understood by engineers until the 1940s, following the collapse of the Tacoma Narrows Bridge ("Galloping Gertie"). Credit for designing the first suspension bridge rigid enough to withstand wind loads and the highly concentrated loadings of locomotives belongs to John Roebling. His first masterpiece was the Niagara Suspension Bridge, with a span of 821ft (250m) on the Grand Trunk Railway below Niagara Falls. The two decks, the upper for the railway and the lower for common road service, were separated by an 18ft (6m) stiffening truss. In addition, the truss was braced with radiating cable stays inclined from the tops of the suspension towers and anchoring cables tying the deck to the sides of the gorge, arresting any tendency to lift under gusts of wind. For the four main cables, Roebling used parallel wires laid up in place but, instead of individual strands like the "garland" system preferred by the French, he bunched the strands together in a single large cable and wrapped them with wire, a technique he patented in 1841 but one that Vicat had illustrated in 1831 in his Rapport sur les ponts en fil de fer sur le Rhône.
Few bridges in the world built since the Brooklyn Bridge in New York (USA) can stand entirely clear of its shadow. Completed in 1883, the plan involved two distinctive stone towers, four main cables, anchorages, diagonal stay cables, and four stiffening trusses separating the common roadway and trolley line from a pedestrian promenade. With a record-breaking span of 1595ft (486m), the Brooklyn Bridge was designed by John Roebling, but it was built by his son and daughter-in-law after he died of blood poisoning following an accident while surveying the location of the Manhattan tower in which his foot was crushed. Massive Egyptian towers, pierced by pointed Gothic arches, stand 276.5ft (84m) above mean high water and 78.5ft (24m) below on the Manhattan side, 44.5ft (14m) on the Brooklyn. Diagonal stay cables give the bridge its distinctive appearance, but function to stiffen the deck. It took two years to lay up each of the four 15.75in (40cm) diameter main cables with 5434 wires, the pioneer use of steel wire (Figure 18).
Figure 18 Brooklyn Bridge (1883) still serves as a majestic portal to Manhattan (USA) for travelers coming from Brooklyn and for ships as they approach from the harbour. The bridge is indelibly linked with New York and, along with San Francisco's Golden Gate, symbolically represents these two famous American cities. Jack Boucher, HAER Collection
Figure 19 Delaware Aqueduct (1849) was being used as a toll bridge in 1969 when it was recorded by the Historic American Engineering Record (HAER), the USA's official engineering heritage program. The towpath of the wooden canal trunk would have been level with the upper most set-back of the masonry piers. David Plowden, HAER Collection
Two other Roebling suspension bridges survive, both recently rehabilitated. One spanning the Ohio River at Cincinnati was completed in 1867. The 1849 Delaware Aqueduct was designed to carry a wooden trunk of water on the Delaware & Hudson Canal. The latter was carefully rehabilitated by the US National Park Service and is the oldest surviving suspension bridge in the USA (Figure 19).
Structural steel is stronger and more supple than cast or wrought iron, and allowed greater design flexibility. The last thirty years of the 19th century witnessed the phasing in of steel plates and rolled shapes, leading to the enormous production of steel trusses and plate-girder spans of ever-increasing lengths throughout the world. Steel arches and cantilevers were favoured for long spans because they better withstood the impact, vibration, and concentrated loads of heavy rail traffic.
The earliest known use of steel in bridge construction was the 334ft (102m) suspension span across the Danube Canal (1828) near Vienna (Austria), designed by Ignaz von Mitis. The steel eye-bar chains were forged from decarburized iron from Styria. Steel halved the weight of wrought iron, but remained prohibitively expensive for another forty years before steelmaking processes such as the Bessemer and the open-hearth were perfected (it is uncertain whether the Styrian ironmasters created real steel or whether the decarburization was a mechanical process resulting in a surface-hardened steel, a kind of wrought iron rather than the mass steel that results from the Bessemer process). The first major bridge utilizing true steel was the Eads Bridge (1874), the most graceful of the Mississippi River crossings in the USA, built by the Keystone Bridge Company, which subcontracted fabrication of the steel parts to the Butcher Steel Works and the iron parts to Carnegie-Kloman, both of Pittsburgh. Its ribbed, tubular steel arch spans of 502ft, 520ft, and 502 ft (153m, 159m, and 153m) and double-decked design shattered all engineering precedents for the time: the centre span was by far the longest arch. Mathematical formulae for the design were developed by Charles Pfeiffer. The cantilever method of erection, devised by Colonel Henry Flad and used for the first time in the USA, eliminated the centring that would have been impossible in the wide, deep, and fast-flowing Mississippi. While recovering from illness in France, the designer James Buchanan Eads found the solution to sinking piers in deep water. He investigated a bridge under construction over the Allier at Vichy that used Cubitt and Wright's pneumatic caissons - floorless chambers filled with compressed air.
The first major bridge of steel in France was the Viaur Viaduct (1902), a three-hinged steel arch of 721ft (220m) flanked by 311ft (95m) cantilevers. The crowning achievement of the material during the 19th century, however, was the mighty Forth Railway Bridge in Scotland (1890). Its design was motivated by the Tay Bridge disaster. About 54,000 tons of Siemens-Martin open-hearth steel were required for the 1710ft (521m) cantilever spans whose main compression struts of rolled steel plate were riveted into 12ft (4m) diameter tubes. Another authority on the effects of wind on structures was Gustav Eiffel, who conducted similar experiments in France prior to designing another of the world's great arch bridges, the 541ft (165m) Garabit Viaduct (1885) in the windy valleys of the Massif Central, though he held to wrought iron, not being convinced of the efficacy of the new material.
Steel arches of enormous span were built during the first few decades of the 20th century. One of the greatest is the Hell Gate Bridge in the USA (1917), a two-hinged trussed arch, the top chord of which serves as part of a stiffening truss. Designed by Gustav Lindenthal to span the Hell Gate at the northern tip of Manhattan Island for the New England Connecting Railroad, it is framed between two massive stone towers. The 978ft (298m) arch, weighing 80,000 tons (81,280 tonnes), was the longest and heaviest steel arch in the world. The next was Bayonne Bridge (1931), which remains one of the longest steel arches in the world today. It was built during the Depression by a team assembled under the direction of Swiss-born and educated engineer, Othmar Ammann, chief engineer of the Port Authority of New York, one of the remarkable public works organizations of the USA, if not the world. Opening three weeks after the George Washington Bridge, then the longest suspension bridge in the world, this second record-breaking span was financed and built by the Port Authority simultaneously, the two projects forming one of the greatest public work endeavours since Roman times. The Bayonne Bridge connects Bayonne (New Jersey) and Staten Island (New York) with a manganese-steel parabolic two-hinged arch of 1675ft (511m) span and 266ft (81m) rise, the deck clearing high water by 150ft (46m). As in the Hell Gate, the arch's top chord acts as a stiffener, the bottom chord carrying the load. The Bayonne Bridge was designed to be 25ft (8m) longer than the nearly identical Sydney Harbour Bridge in Australia, started five years earlier.
Bridges in areas other than Europe and the USA should be investigated, as the colonial empires of several nations were at their peak during the autumn years of the 19th century. In India, for example, the British built several long-span railway bridges, such as the Hooghly and the Sukkur bridges which exceeded 1000ft (300m) in span and are interesting because they were constructed using the simplest equipment and armies of unskilled labour.
This structural form was mentioned in the previous section on steel bridges in the discussion of the Eads Bridge, where the erection of the arches employed principles of the cantilever, and the Forth Railway Bridge, perhaps the world's greatest cantilever. A discussion of this type of bridge is warranted because of its engineering interest and because the form illustrates the outstanding application of iron and steel to bridge construction.
Cantilevers were one of the first bridge types, many being built by the ancient cultures of China and India. The first modern cantilever was Heinrich Gerber's Hassfurt Bridge over the Main in Germany (1867), with a central span of 124ft (38m). It was a continuous girder hinged at the points of equal resistance where the moments of the uniform load were zero. According to W Westhofen, who wrote the classic account of the Forth Bridge, the idea first was suggested by John Fowler, co-designer of the Forth Bridge, around 1846-50. In Britain and the USA the form was known as cantilevers, in France as portes-à-faux, and in Germany as the Gerber Bridge, named after the builder. By inserting hinges, the continuous girder can be made statically determinant. This was their first attribute, but later as the possibility of erection without scaffolding was recognized - the ability of the arms of the bridge to be built out from the piers, balancing each other without the need for falsework. This became the great advantage. The principle also is applicable to other bridge types such as arches, an example being the Eads Bridge, where the width, depth, and current of the mighty Mississippi prevented the erection of falsework.
In 1877, C Shaler Smith provided the first practical test of the principle when he built what then was the world's longest cantilever over a 1200ft (366m) wide and 275ft (84m) deep gorge of the Kentucky River near Dixville, Kentucky (USA). The cantilever resolved the difficulty of erecting falsework in a deep wide gorge. The anchor arms were 37.5ft (11m) deep Whipple trusses that extended 75ft (23m) beyond the piers. From these were hung 300ft (91m) semi-floating trusses fixed at the abutments and hinged to the cantilever, making the overall span from pier to abutment 375ft (114m). The bridge was rebuilt in 1911 by Gustav Lindenthal using the identical span lengths, but with trusses twice as deep.
The next important cantilever was a counterbalanced span designed by C C Schneider for the Michigan Central Railroad over the Niagara Gorge in 1883. With arms supporting a simple suspended truss, this 495ft (151m) span and the nearly identical Fraser River span in British Columbia (Canada) directed the attention of the engineering world to this new type of bridge. These two were the prototypes for subsequent cantilevers at Poughkeepsie, New York, the Firth of Forth Bridge in Scotland, and the Québec Bridge in Canada.
The Poughkeepsie Cantilever (1886) was the first rail crossing of the Hudson River below Albany, 55 miles (89km) north of New York City. Built by the Union Bridge Company of New York to designs by company engineers Francis O'Rourke and Pomeroy P Dickinson, the overall length is 6768ft (2063m), including two cantilevers of 548ft (167m) each. Strengthened in 1906 by adding a third line of trusses down the middle designed by Ralph Modjeski, citizens on both sides of the river are working to have this magnificent, but now abandoned, bridge incorporated as part of the Hudson Greenway trail system.
Figure 20 Forth Bridge (1890): an historic photograph showing the FifeTower at North Queensferry, Scotland (UK), nearing completion. The illustration is from Wilhelm Wethofen's article published in Engineering Magazine, 28 February 1890.
The world's most famous cantilever also is one of the world's first and largest steel bridges and held the record for longest cantilever for 27 years. Pontists are familiar with the brilliant demonstration used by Sir Benjamin Baker to illustrate the structural principles of the Firth of Forth Bridge: two men sitting on chairs with outstretched arms and sticks supporting Kaichi Watanabe, a visiting engineering student from Japan, sitting on a board, representing the fixed piers, cantilevers, and suspended span. To ensure that there was no repeat of the Tay disaster, Baker conducted a series of tests, gauging wind at several sites in the area over a two-year period, arriving at a design pressure of 56lb/ft2 (274kg/m2), which was considerably in excess of any load the bridge would ever sustain. Each of the two main spans of the bridge consists of two 680ft (207m) cantilevers with a 350ft (107m) suspended span for a total length of 1,710ft (521m). John Fowler and Benjamin Baker designed the Forth Bridge (1890) to resist wind loads 5.5 times those that toppled the Tay Bridge (Figure 20).
The Forth Bridge's record was broken in 1917 when the Québec Bridge was finally completed, spanning the St Lawrence River near Québec (Canada) with an 1800ft (549m) cantilever span. Its predecessor failed in 1907 while under construction, killing 82 workmen and ending the career of one of America's most prominent engineers. Theodore Cooper had taken the commission reluctantly with a fee insufficient to hire assistants, to allow for written specifications, or to provide for on-site inspections. The design was not recalculated when Cooper, intent on exceeding the span of the record-holding Forth Bridge, increased it from 1600ft to 1800ft, which was ultimately to result in the failure of one of the main compression members of the lower chord in the south anchor. The second bridge also had its problems as well when one of the jacks failed while lifting the 5000 ton centre suspended span, dropping it into the river. A duplicate truss was successfully lifted into place within two weeks and the bridge was finally opened. This bridge, designed by E H Duggan and Phelps Johnson with Ralph Modjeski as consultant, was criticized by many engineers as being the ugliest, while the cantilever was generally regarded as a type, especially those of American origin, whose profile was unsightly despite their record lengths.
The largest cantilever in Europe was Saligney's Danube Bridge near Czernavoda (Romania), with a span of 623ft (190m). Another great cantilever is the Howrah Bridge over the Hooghly River at Calcutta (India), with a span of 1500ft (457m).
Reintroduction of masonry and concrete
Concrete is an ancient material. It was first discovered and used by the Romans in their aqueducts and temples, to be sporadically rediscovered throughout time by engineers who used it in its mass- poured form. The discovery of natural cement in 1796, on the Isle of Sheppey in the Thames Estuary (UK), renewed interest in the material, but the age of concrete began its most vigorous development with Joseph Aspdin's invention in 1824 of artificial Portland cement. This mixture of clay and limestone, calcined and ground, resulted in a material having broad application for buildings and bridges. The scientific studies of Vicat on natural and artificial cements initiated in 1816 at the Pont de Souillac (France) revealed the first understanding of the chemical properties of hydraulic cement. Canvass White, an engineer on the Erie Canal (USA), discovered natural cement in 1818 and established a mill to manufacture the substance at Chittenango, New York. The primary benefit of the material was its ability to set under water. Naming it hydraulic cement, he patented the process in 1819 and used it for aqueducts, abutments, culverts, and lock walls.
In 1831, Lebrun, a French engineer, designed the first concrete bridge to span the River Agout, although it never was built. A significant early structural use of concrete in the USA was in 1848 for the foundations and deck of the Starrucca Viaduct on the New York & Erie Railroad, a mighty stone-arched bridge with an overall length of 1040ft (317m), designed by Julius Walker Adams and built by James Pugh Kirkwood.
Later, the use of artificial cement combined with more sophisticated understanding of the mathematical principles of arch theory resulted in renewed interest in stone and masonry arch bridges in Europe. Beginning in the mid-19th century, masonry railroad viaducts were an important civil engineering technology for continental Europe. The most impressive were the 1969ft (600m) long Chaumont Viaduct (1857) and the 240ft (73m) high Sainte-Brieuc (Barentin) Viaduct (1860), both in France, and the Goltzschtal Viaduct in Germany, which used 26 million units of brick.
The French engineer, Paul Séjourne, expressed the most elegant modern restatement of the principles of this most ancient material in his masterpiece bridges of stone, the 279ft (85m) span Pont Adolphe in Luxembourg (1903) and the bridge at Plauen, Germany (1905), which was the longest ever achieved in stone masonry, with a span of 295ft (90m).
The beginning of concrete as a major material of bridge construction dates from 1865, when it was used in its mass, unreinforced form for a multiple-arch structure on the Grand Maître Aqueduct conveying water from the River Vanne 94 miles (151km) to Paris. Engineers in the late 19th century demonstrated the possibilities of reinforced concrete as a structural material. With concrete resisting compressive forces and wrought iron and steel bars carrying tension, bridges of dramatic sweeping curves evolved. Today's long-span reinforced- concrete bridges are descended from French gardener Joseph Monier's flower pots and his numerous bridge patents granted between 1868 and 1878. He is credited with being the first to understand the principles of reinforced concrete when in 1867 he patented plant tubs of cement mortar strengthened with iron-wire mesh embedded in the concrete and moulded into curvilinear forms. Not being an engineer, he was not permitted to build bridges in France and so he sold his patents to German and Austrian contractors Wayss, Freitag and Schuster, who built the first generation of reinforced concrete bridges in Europe: the Monierbrau 131ft (40m) footbridge in Bremen (Germany) and the Wildegg Bridge, with a span of 121ft (37m), in Switzerland. Additional patents were granted in Belgium, France and Italy, especially to the Frenchman François Hennebique, who established the first international firm to market his bridges before World War I. His first masterpiece was built at Millesimo (Italy) in 1898, and that at Châtellérault in France (1900) remains as one of the first notable reinforced concrete arch bridges in the world, with a central span of 172ft (52m) and two lateral arches of 131ft (40m). In 1912, Hennebique set a new world record with a bridge over the Tiber in Rome (Italy) with a span of 328ft (100m). Other important three-span bridges with impressive central spans were built in France by Eugène Freyssinet, such as the bridges at Veurdre (1910) and Boutiron (1912).
In France, where much of the original thinking on reinforced concrete occurred, the record span was the Saint-Pierre du Vauvray Bridge (1922) by Freyssinet. He perfected the technique of prestressing concrete by inserting hydraulic rams in a gap left at the crown of arches, then activating the rams to lift the arches off the falsework and filling the gap with concrete, leaving only permanent compressive stresses in the arches. The Vauvray Bridge over the Seine was the record span at 430ft (131m), the deck being hung from hollow cellular arch ribs on wire hangers, coated with cement mortar, and supporting the road on light concrete deck trusses. The Vauvray Bridge was destroyed in World War II, leaving the Plougastel Bridge (1930) over the River Elon at Brest, with three spans of 567ft (173m), as the longest reinforced concrete arch span until 1942.
Swiss engineer Robert Maillart designed three-hinged arches in which the deck and the arch ribs were combined to produce closely integrated structures that evolved into stiffened arches of very thin reinforced concrete and concrete slabs, as at the Schwandbach Bridge (1933), near Schwarzenbach (Switzerland). Maillart's early apprenticeship with Hennebique sharpened his awareness of the plastic character of the material. His profound understanding of reinforced concrete allowed him to develop new, light, and magnificently sculptural forms. Maillart's bridges are of two distinct types: stiffened-slab arches and three-hinged arches with an integrated road slab. The 295ft (90m) Salginatobel Bridge (1930) near Schiers (Switzerland) is the most spectacular and classic example of this type in the world.
The world's longest concrete and masonry arch bridge is the Rockville Bridge (1902), which carries four tracks of the former Pennsylvania Railroad over the Susquehanna River (USA) on 48 arches, 70ft (21m) each, for a total length of 3820ft (1164m). It was part of a massive twenty-year improvement programme under the direction of William H Brown, chief engineer. The largest all- reinforced concrete bridge, however, is the Tunkhannock Viaduct (1915) built by the Delaware, Lackawanna & Western Railroad in north-eastern Pennsylvania (USA), composed of ten semi-circular double-arch spans of 180ft (55m) with the spandrels filled with eleven smaller arches. Like Rockville, it was a major component in another early 20th century US railroad improvement project, this time a massive realignment. Abraham Burton Cohen was the rail line's designer of the reinforced-concrete bridges.
The first major reinforced-concrete bridge in the United Kingdom was the Royal Tweed Bridge (1928), made up of four rhythmic open- spandrel arches filled with vertical posts increasing in span from 167ft (51m) to 361ft (110m) as the roadway climbs from low to high embankments on each side of the river.
Sweden is another country that excelled in building elegant and innovative reinforced-concrete arch bridges of extremely long span. The first was the Traneberg Bridge (1934) in Stockholm, designed by Harbour Board engineers Ernst Nilsson and S Kasarnowsky with Eugène Freyssinet consulting. Its 593ft (181m) span was surpassed briefly in 1942 by the Esla Bridge in Spain with a span of 631ft (192m), but within the same year the title for the longest arch was regained for Sweden by S Haggböm with the Sando Bridge, the longest reinforced- concrete arch in the world at 866ft (264m).
Moveable and transporter bridges
This essay ends with two of the oldest types of bridges known to humankind. The bascule or draw span was developed by Europeans during the Middle Ages. There was a resurgence of moveable bridges during the late 19th century. Reliable electric motors and techniques for counterbalancing the massive weights of the bascule, lift, or swing spans marked the beginning of modern moveable-bridge construction. They are usually found in flat terrain, where the cost of approaches to gain high-level crossings is prohibitive, and their characteristics include rapidity of operation, the ability to vary the openings depending on the size of vessels, and the facility to build in congested areas adjacent to other bridges.
Completion of Tower Bridge over the Thames in London (1894), a 260ft (79m) roller-bearing trunnion bascule and the best known bascule bridge in the world, and Van Buren Street Bridge in Chicago, the first rolling lift bridge in the USA (patented by William Scherzer), marks the efficient solution to problems of lifting and locking mechanisms. In 1914, the Canadian Pacific Railroad completed the world's largest double-leaf bascule, spanning 336ft (102m) over the ship canal at Sault-Sainte-Marie, Michigan, rebuilt with identical spans in 1941. The Saint Charles Airline Railway Bridge (1919) spanning 16th Street in Chicago was at 260ft (79m) the longest single-leaf bascule when it was completed. In 1927, the Atchison, Topeka & Santa Fe Railroad built the world's longest single-span swing bridge, 525ft (160m), over the Mississippi at Fort Madison, Iowa. One of the most interesting and unusual moveable bridges is the Lacey V Murrow Bridge (1940), whose design reached back to the pontoons built by Roman legions. The depth and breadth of the lake precluded the construction of conventional piers on pilings, cantilever, or suspension spans, and so Washington State bridge engineers designed a floating bridge supported by hollow concrete pontoons to connect Seattle and Mercer Island. Equally unique was the retractable floating draw span for ocean-going ships in the lake. Three other bridges of this type were completed over the Hood Canal (1961) and at Evergreen Point (1963). A span parallel to the Murrow Bridge now carries the increased traffic of Interstate Highway 90.
A comparable example of an unusual type of moveable bridge in Europe is the transporter bridge, where a platform suspended by cables from tall towers and superstructure is carried on an overhead framework. This type of bridge also reaches back into history, integrating ancient technology such as the rope ferry with new structural forms and materials such as the iron beam and the strongest steel cables. The transporter bridge was the original solution to spanning the mouth of a river or entrance to a harbour and also served as a monumental gateway. Although it was patented in the UK and the USA in the mid 19th century, the first significant example was built by French engineer Ferdinand Arnodin, at Portugalete (1893) in Spain. Arnodin also invented the twisted steel cable, an important innovation for this type of bridge. The only other survivors are located in the United Kingdom at Middlesbrough and Newport (Wales) and at Martrou (France).
The author deeply appreciates the review and comments on this essay by the following individuals: Dr Shunsuke Baba (Faculty of Environmental Science and Technology, Okayama University, Japan), Professor Louis Bergeron (École des Hautes Études en Sciences Sociales, Paris, France), Sir Neil Cossons (Director, Science Museum, London, UK), Dott. Roberto Gori (Università di Padova, Italy), Dr Emory Kemp (Director, Institute for the History of Technology and Industrial Archaeology, West Virginia University, USA), Dr Michael Mende (Hochschule für Bildende Kunst, Braunschweig, Germany), David Simmons (Editor, Timeline, Ohio Historical Society, Columbus, USA), Dr Itoh Takasaki (Research Institute of Science and Technology, Nihon University, Japan), and Robert Vogel (Curator Emeritus, Museum of American History, Smithsonian Institution, Washington, DC, USA).
He is especially indebted to Michel Cotte (Tournon, France), whose review provided insights on bridge types, chronological structure, and other subtleties of European bridge history that the author was not aware of. His thorough review gives this paper a solid European foundation.
POTENTIAL WORLD HERITAGE BRIDGES
Clapper Bridges (Bronze Age): Dartmoor, Devon, England (UK)
Bridges of twisted vines & creepers: India, Africa, South America
Ponte Saint-Martin (c 25 BC): near Torino (Italy)
(*)Puente Romano (1 BC, AD 5): Mérida (Spain)1
Alcantara Bridge (AD 98): near Cáceres (Spain)2
Ancient cantilevers: Japan, China, Tibet3
Zhaozhou Bridge (c 605): Beijing vicinity (China)
Phra Bhutthos (12th century): Kompong Kdei vicinity (Cambodia)4
Jiangdonggiao (1565): (China)5
Shogun's Bridge (1638): Nikko (Japan)
Bridge of Khaju (1667): Isfahan (Iran)
Kintaikyo (1673): Iwakuni (Japan)
(*)Bridge over the Tigris (1065): Diyarbakir (Turkey)
(*)Bridge over the Batman River (1146), Malabadi (Turkey)
(*)Steinerne Brücke (1146): Regensburg (Germany)
Monnow Bridge (1272, 1296): Monmouth, Wales (UK)
(*)Puente del Diablo (1290): Martorell, Barcelona (Spain)
(*)Arabic Bridge (14th century): Arevalo, Ávila (Spain)
(*)Ponte della Maddalena (1345): Borgo a Mazzano, Tuscany (Italy)
Ponte Vecchio (1345): Florence, Italy6
Pont d'Avignon (c 1350): France
Pont Valentré (1355): Cahors (France)
(*)Karluv Most (1357): Prague (Czech Republic)
Renaissance and Neo-Classical
(*)Old Bridge over the Main (1543): Würzburg (Germany)
Ponte Santa Trinità (1569): Florence (Italy)
Rialto Bridge (1591): Venice (Italy)
Pont Neuf (1607): Paris (France)7
Aqueduct at Tomar (1613) and Elvas (1622): Portugal
Ratisbonne Bridge over the Danube: Germany (nd)
Dresden Bridge: Germany (nd)
Bridge over the Gironde: Bordeaux (France) (nd)
Pontypridd Bridge (1756): South Wales (UK)
(*)Kapellenbrücke (1333), Paintings (1611): Lucerne (Switzerland)
Bassano Bridge (1561, 1948): Bassano della Grappa (Italy)
Rumlangbrücke (1766): Switzerland
(*)Bridge over the Rhine (piers 1580, wood superstructure c 1800): Sackingen (Switzerland/Germany)
(*)Bridge over the Rhine (1804): Reinhau (Switzerland)
(*)Bridge over the Rhine (1816): Diessenhofen (Switzerland/Germany)
(*)Bridge over the Jagst (early 19th century): Unterregenbach (Germany)
Bridgeport Bridge (1862): Grass Valley, California (USA)
Cornish-Windsor Bridge (1866): New Hampshire/Vermont (USA)
Cast-iron arches in Tsarskoye Selo (18th century): St Petersburg (Russia)8
Decorative bridges (18th century): Ducal Gardens of Wörlitz, Dessau (Germany)9
Pont-y-Cafnau aqueduct and tramway bridge (1793): Merthyr Tydfil, Wales (UK)10
Pontcysyllte Aqueduct (1795): Llangollen, Wales (UK)
Rio Cobre Bridge (1800): Spanish Town (Jamaica)
Gaunless Viaduct (1825): National Railway Museum, York, England (UK)
Dunlaps Creek Bridge (1839): Brownsville, Pennsylvania (USA)
Laves Beam Bridge (1844): Royal Gardens, Hannover (Germany)
Philadelphia & Reading Railroad, Hall's Station Bridge (c 1846): Pennsylvania (USA)
Conwy Castle Bridge (1848): Wales (UK)
High Level Bridge (1849): Newcastle upon Tyne, England (UK)
Royal Albert Bridge (1859): Saltash, Cornwall, England (UK)
(*)Waldshut-Koblenz Railroad Bridge over the Rhine (1859): Switzerland/Germany
Cast-iron arches in Central Park (1860s): New York City (USA)
(*)Kleve-Griethausen Bridge over the Lower Rhine (1865): Germany
Whipple Truss Bridge (1867): Normanskill Farm, Albany, New York (USA)
Baltimore & Ohio Railroad, Bollman Truss Bridge (c 1869): Savage, Maryland (USA)
(*)Schwedler Arch-Truss Railroad Bridge over the Elbe (1873): Langendorf (Germany)
Ponte Ferroviaria de Dona Maria Pia (1877): Italy
(*)Maria Pia Bridge (1877): Oporto (Portugal)
(*)Dom Luiz I Bridge (1886): Oporto (Portugal)
Railroad Viaducts & Trestles
Baltimore & Ohio Railroad, Thomas Viaduct (1835): Maryland (USA)
Boston & Providence Railroad, Canton Viaduct (1835): Massachusetts (USA)
Balcombe Viaduct (1839): West Sussex, England (UK)
Viaduc de Barentine (1846): France
Ballochmyle Viaduct (1846): Cumnock, Scotland (UK)
Viaduc de Saint-Chamas (1847): France
Chappel Viaduct (1847): Essex, England (UK)
New York & Erie Railroad, Starrucca Viaduct (1848): Lanesboro, Pennsylvania (USA)
(*)Goltzschtal Viaduct (1851): Netschkau vicinity (Germany)
Viaduc de la Bouble (1871): France
Meldon Viaduct (1871, 1879): Okehampton, Devon, England (UK)
Viaduc de Garabit (1885): Saint-Fleur vicinity (France)
New York & Erie Railroad (Bradford Branch), Kinzua Viaduct (1900), Pennsylvania (USA)
Glenfinnian Viaduct (1897): Highland Region, Scotland (UK)
Wüppertal Tramway System (1913): Wüppertal (Germany)
Railway Bridge over Kiel Canal (1913): Rendsburg (Germany)
Lethbridge Viaduct (1909): Alberta (Canada)
Delaware, Lackawanna & Western Railroad, Tunkhannock Viaduct (1915): Nicholson, Pennsylvania (USA)
Union Bridge (1820): Berwick-on-Tweed, England (UK)
Menai Suspension Bridge (1826): Wales (UK)
Conwy Suspension Bridge (1826): Wales (UK)
(*)Szechenyi Bridge (1849, 1915, 1949): Budapest (Hungary)
Tain-Tournon Bridge (1847): France
Delaware & Hudson Canal, Delaware Aqueduct (1849): Lackawaxen, Pennsylvania (USA)
Wheeling Suspension Bridge (1849): West Virginia (USA)
Clifton Suspension Bridge (1864): Bristol, England (UK)
Brooklyn Bridge (1883): New York City (USA)
Pont Rail Gisclard (1909): France11
Acueducto de Tempul (1925): Spain
Eads Bridge (1874): St Louis, Missouri (USA)
(*)Railway Bridge over the Danube between Fetesti and Czernadova (1895): Romania
(*)Mungstener Brücke (1897): Germany
Viaur Viaduc (1902): France
New York Connecting Railroad, Hell Gate Bridge (1917): New York City (USA)
(*)Road bridge over the Rhine (1928): Nijmegen (Netherlands)
Bayonne Bridge (1931): Bayonne, New Jersey (USA)
Sydney Harbour Bridge (1931): Sydney (Australia)
Poughkeepsie Cantilever (1886): Poughkeepsie, New York (USA)
Forth Railway Bridge (1890): Scotland (UK)
Québec Bridge (1917): Canada
Reinforced concrete bridges
Pont de Châtellérault (1900): France
Pennsylvania Railroad, Rockville Bridge (1902): Rockville, Pennsylvania (USA)
Risorgimento Bridge (1911): Rome (Italy)
Royal Tweed Bridge (1928): Berwick-on-Tweed, England (UK)
Plougastel Bridge (1930): Brest (France)
Salginatobel Bridge (1930): Schiers (Switzerland)
Schwandbach Bach Bridge (1933): Schwarzenbach (Switzerland)
Traneberg Bro (1934): Stockholm (Sweden)
(*)Motorway Bridge (1938): Stadtroda (Germany)
Viaducto Ferrioviario Francisco Martín Gil (1942): Spain
Sandö Bro (1942): Sweden
Strömsund Bro (1955): Sweden
Moveable and transporter bridges
(*)Puente de Vizcaya (1891): Portugalete (Spain)12
Martrou Bridge over the Charente: France (nd)
Barton Swing Aqueduct (1893): Eccles, England (UK)
Tower Bridge (1894): London, England (UK)
Middlesbrough Transporter Bridge (1911): England (UK)
Atchison, Topeka & Sante Fe Railroad, Fort Madison Bridge (1927): Fort Madison, Iowa (USA)
Lacey V Murrow Bridge (1940): Seattle, Washington (USA)
Canadian Pacific Railroad, Sault-Sainte-Marie Bridge (1941): Michigan (USA)
- Bridges marked (*) were suggested by Michael Mende.
- The Pont du Gard (France), the Segovia Aqueduct (Spain), and other Roman and Renaissance bridges in the historic centres of Rome, Florence, and Segovia are already on the World Heritage List.
- Primitive bridges, if any survive, may be candidates for World Heritage listing because they illustrate primitive ingenuity and craft technology, which it is important to recognize and preserve.
- The Phra Bhutthos (Cambodia), the Jiangdonggiao (China), the Ponte Saint-Martin (Italy), the Steinerne Brücke (Germany), Pontypridd Bridge (UK), Rumlangsbrücke (Switzerland), the Menai Suspension Bridge (UK), the Puente Ferroviario de Dona Maria Pia (Italy), Strömsund Bro (Sweden), the Pont Rail Gisclard, and Acueducto de Tempul (Spain) were suggested by Professor Shunsuke Baba.
- Stone girder of 76ft (23m) span, total length of bridge 920ft (281m).
- The Ponte Vecchio and the Ponte Santa Trinità form part of the Florence World Heritage site. The Ponte Vecchio replaced a similar bridge that failed in 1333. Some authorities attribute its design to Fra Giovanni da Campi rather than the architect Taddeo Gaddi.
- The Pont Neuf and several other bridges over the Seine form part of the Paris - Banks of the Seine World Heritage site.
- Several collections of cast-iron arches survive in different countries. The largest is in England, there are six in the USA, a few in France, and a remarkable selection in Russia, all of which could be studied as a specific type with the object of possible eventual World Heritage nomination.
- Most of these bridges were designed by Friedrich Wilhelm von Erdmannsdorf and not all are iron. They include the Roman Bridge (1788), the tree-trunk Hornzachenbrücke (1774), the Treppenbrücke, based on the Mathematical Bridge in Cambridge (1773), the Wolfsbrücke (1811), the Chinese Chain Bridge (1781), the Sun Bridge (1796), and the Iron Bridge (1791).
- A case for the world significance of this bridge was made by Stephen Hughes of the Royal Commission on the Ancient and Historical Monuments of Wales.
- This and the Acueducto de Tempul, designed by Albert Gisclard and Eduardo Torroja respectively, are possible candidates for listing as early cable-stayed suspension bridges.
- A suspension ferry (transporter bridge) 525ft (160m) long by 141ft (43m) high.
American Bridge Books
Condit, Carl W American Building Art, 19th & 20th Century, 2 volumes, Oxford University Press, New York, 1961.
DeLony, Eric Landmark American Bridges. American Society of Civil Engineers, New York; Bullfinch Press, Little Brown Publishing Company, Boston, 1993.
DeLony, Eric World Timetable of Bridges. Unpublished manuscript, 1997.
de Jonge, Riveted Joints: A Critical Review of the Literature Covering their A E Richard Development, with Bibliography and Abstracts of the Most Important Articles. The American Society of Mechanical Engineers, New York, 1945.
Du Bois, A J The Elements of Graphical Statics and Their Application to Framed Structures. John Wiley & Son, New York, 1875.
Dufour, Frank O Bridge Engineering. American Technological Society, Chicago, 1931. & Schantz, C Paul
Edwards, A Record of History & Evolution of Early American Bridges, University Llewellyn N of Maine Press, Orono, 1959.
Haupt, Herman General Theory of Bridge Construction. D Appleton & Company, New York, 1851.
Hool, George A Moveable and Long-Span Steel Bridges. (1st ed) McGraw-Hill Book & Kinne, W S (eds) Company, New York, 1923.
Jackson, Donald C Great American Bridges & Dams. The Preservation Press, Washington, DC, 1988.
Jakkula, A A A History of Suspension Bridges in Bibliographical Form. Bulletin of the Agricultural and Mechanical College of Texas, Fourth Series, vol 12, no 7, July 1, 1941. Federal Works Agency, Public Roads Administration, Washington, DC. 1941.
Johnson, J B, The Theory and Practice of Modern Framed Structures. (7th ed.). John Bryan, C W, & Wiley & Sons, New York, 1902. Turneaure, FE
Ketchum, Milo S The Design of Highway Bridges. The Engineering News Publishing Company, New York, 1908.
Mahan, D H A Treatise on Civil Engineering. J Wiley & Sons, New York, 1873.
Melan, Joseph Plain and Reinforced Concrete Arches. (1st ed) John Wiley & Sons, New York, 1915.
Parsons, Engineers and Engineering in the Renaissance. William & Wilkins, William Barclay Baltimore, 1939.
Peters, Tom F Transitions in Engineering. Birkhauser Verlag, Basel, Switzerland and Boston, 1987.
Plowden, David Bridges: Spans of North America. The Viking Press, New York, 1974.
Pope, Thomas A Treatise on Bridge Engineering. Printed for the Author by Alexander Niven, New York, 1811.
Schodek, Daniel L Landmarks in American Civil Engineering. MIT Press, Cambridge, MA and London, 1987.
Scott, Quint The Eads Bridge. University of Missouri Press, Columbia, 1979. & Miller, Howard S
Smith, H Shirley The World's Great Bridges. Harper & Row, New York, 1965.
Steinman, D B A Practical Treatise on Suspension Bridges. John Wiley & Sons, New York, 1922.
Stephens, John H Towers, Bridges, and Other Structures. Sterling Publishing Company, New York, 1976.
Timoshenko, History of Strength of Materials. McGraw-Hill, New York, 1953. Stephen P
Tyrrell, History of Bridge Engineering. Published by the author, Chicago, 1911. Henry Grattan
Waddell, J A L The Designing of Ordinary Iron Highway Bridges. John Wiley & Sons, New York, 1894.
Watson, Wilbur J Bridge Architecture. William Helburn Inc, New York, 1927.
Whitney, Charles S Bridges: A Study in Their Art, Science and Evolution. William Edwin Rudge, New York, 1929.
Woodward, A History of the St. Louis Bridge; Containing A Full Account of Every Calvin Milton Step in its Construction and Erection, and Including the Theory of the Ribbed Arch and the Tests of Materials. G I Jones & Company, St Louis, 1881.
British Bridge Books
Burnell, George R, Supplement to the Theory, Practice and Architecture of Bridges. John ed Weale, London, 1850.
Cossons, Neil The BP Book of Industrial Archaeology. David & Charles, Newton Abbot, London, North Pomfert (VT), 1987.
de Maré, Eric Bridges of Britain. B T Batsford Ltd., London & Sydney, 1975.
Dempsey, Tubular and other Iron Girder Bridges, Particularly Describing the G DrysdaleBritannia and Conway Tubular Bridges. John Weale, London, 1850.
Fidler, T Claxton A Practical Treatise on Bridge-Construction. Charles Griffin & Co., London, 1887.
Hopkins, H J A Span of Bridges: An Illustrated History. David & Charles, Newton Abbot, Devon, 1970.
Hosking, William Bridges: In Theory, Practice, and Architecture. John Weale, London, 1839.
James, J G The Evolution of Iron Bridge Trusses to 1850, The Newcomen Society Transactions, vol 52, 1980-81, London, 1982.
Kemp, Emory L Thomas Paine and His Pontifical Matters, ibid, vol 49, 1977-78, London, 1979.
Richards, J M The National Trust Book of Bridges. Jonathan Cape, London, 1984.
Weale, John, ed The Theory & Practice and Architecture of Bridges of Stone, Iron, Timber & Wire with Examples on the Principle of Suspension, Vol.1. John Weale, London, 1843.
Westhofen, W The Forth Bridge. Reprinted from Engineering, February 28, 1890, London, 1890.
Wright, Lewis The Clifton and Other Remarkable Suspension Bridges of the World. John Weale, London, 1865.
French Bridge Books
Annales des Ponts et Chaussées, Célébration du 150e Anniversaire (1831-1981) de la Fondation de la Revue, No.19, 3e Trimestre, Paris, 1981.
Aragon, E Ponts en bois et en métal, Bibliothèque du Conducteur de Travaux Publics, H Dunod et E Pinat, Éditeurs, Paris, 1911.
Cotte, Michel Le système technique des Séguin en 1824-1825, History & Technology, 7-2, (pp 119-147), 1990.
Cotte, Michel L'accident du Pont Angers, Revue, Musée des Arts et Métiers, pp 4-15, 5 décembre 1993.
École Nationale des Ponts et Chaussées, No 14, Paris, octobre 1961.
Grattesat, Guy Ponts de France. Presses de l'École Nationale des Ponts et Chaussées, Paris, 1982.
Marrey, Bernard Les ponts modernes: 18e-19e siècles, Picard Éditeur, Paris, 1990.
Mesqui, Jean Le pont en France avant le temps des ingénieurs, Picard, Paris, 1986.
Perronet, J R Description des projets et de la construction des Ponts de Neuilly, de Mantes, d'Orléans, de Louis XVI, etc, de l'Imprimerie de François-Ambroise Didot, Paris, 1788.
Picon, Antoine L'invention de l'ingénieur moderne: l'École des Ponts et Chaussées (1747-1851), Presses de l'École Nationale des Ponts et Chaussées, Paris, 1992.
Polonceau, A R Nouveau système des ponts en fonte, suivi dans la construction du Pont du Carrousel, Carilian-Goeury et Dalmont, Éditeurs, Libraires des Corps Royaux des Ponts et Chaussées et des Mines, Paris, 1839.
Prade, Marcel Les ponts monuments historiques. Brissaud, Poitiers, 1986.
Prade, Marcel Ponts et viaducs au XIX siècle. Brissaud, Poitiers, 1987.
Prade, Marcel Ponts remarquables d'Europe. Brissaud, Poitiers, nd.
Prade, Marcel Les grands ponts du monde: hors de l'Europe. Brissaud, Poitiers, 1992.
German Bridge Books
Boeyng, Ulrich Die ältesten eisernen Brücken der Deutschen Bundesbahn in Baden-Württemberg. Sonderforschungsbereich 315 der Universität Karlsrühe, Karlsrühe, 1988.
Leonhardt, Fritz Brücken, Bridges. The MIT Press, Cambridge, MA, 1984.
Mehrtens, Georg Der deutsche Brücken im 19. Jahrhundert (Reprint of 1900 edition). Düsseldorf, 1984.
Trautz, Martin Eiserne Brücken in Deutschland im 19. Jahrhundert. Düsseldorf, 1991. Wagner, R Die ersten Drahtkabelbruken. Werner- Verlag, Düsseldorf, 1987. & Egermann, R
Wittfoht, Hans Building Bridges: History, Technology, Construction. Beton- Verlag, Düsseldorf, 1984.
Swiss Bridge Books
Bill, Max Robert Maillart. Girsberger, Zürich, 1955.
Killer, Josef Die Werke der Baumeister Grubenmann. Zürich, 1959.
Pottgiesser, Hans Eisenbahnbrücken aus Zwei Jahrhunderten. Basel, 1985.
Italian Bridge Books
Jodice, R L'architettura del ferro, l'Italia. Bulzoni, Roma, 1985.
Siviero, E Il ponte e l'architettura. Città Studi Edizione, Milano, 1995.
Siviero, E, Casucci, Studi e recupero del ponte. Biblioteca di Galileo, Padova, 1995. R, & Gori, R
The author is Chief of the Historic American Engineering Record, National Park Service, US Department of the Interior. He may be contacted at the following address:
Eric DeLony, Historoic American Engineering Record, National Park Service, PO Box 37127, Washington, D.C 20013-7127, USA
© ICOMOS and TICCIH 1996