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December 12, 2000

And The Walls Didn't Come Tumbling Down
Published on:  December 12, 2000
Page 22 

— This old house in Istanbul survived the 1999 earthquake - not even the bag (hanging on the wall) fell down © Randolph Langenbach

In earthquake-prone areas, traditional building techniques offer some remarkable solutions.

Many will have seen the heart-rending images of collapsed reinforced-concrete apartment buildings that featured on news bulletins worldwide following the August 17 earthquake in Northern Turkey last year. But few, perhaps, will have noticed the many brick-and-timber houses constructed using traditional methods still standing amid the ruins. However, the fact that so many of them did, mocked conventional wisdom that local masonry construction was unsafe compared to modern reinforced concrete. It also drew attention to this form of traditional or vernacular construction, which is fast disappearing from Turkey’s urban landscapes.

BETTER ADAPTED:  It was with these things in mind – the loss of the important expression of the built cultural heritage that such architecture represents, together with its impressive performance in earthquakes – that UNESCO, together with ICOMOS, the Inter-national Council on Sites and Monuments, and the Turkish Ministry of Culture organised an international conference to investigate such architecture further. In the words of UNESCO’s Francis Childe, a co-organiser of the conference, “the question is whether, in importing convenient, reinforced-concrete construction methods into areas of high seismic risk, traditional construction methods, better adapted to such areas, may not have been overlooked. And if they have been overlooked, it is our duty to ask what could be learned from such techniques.”

Researchers and architects have rarely addressed the special seismic properties of vernacular architecture, and it is generally accorded little prestige, being seen as “primitive” or unsophisticated when compared to reinforced-concrete buildings. Yet, according to Randolph Langenbach, Senior Analyst at the Federal Emergency Management Agency in the United States and a former Professor of Architecture at the University of California, Berkeley, such buildings “form the cultural context of any civilization – helping to provide us with an understanding of past lives in ways that individual monuments sometimes cannot.” They also “can tell us how people in the past confronted the problem of creating structures in which to live and work under the influence of adversities (including) the most extreme threat of all, large earthquakes.”

Food for thought:  It is tragic, he points out, that in “modern cities like Istanbul, which as recently as 50 years ago was filled with wooden houses, almost all (the vernacular buildings) have been knocked down, often within the space of a single generation.” It is essential, Langenbach says, to respect the work of past generations in order to understand “the contribution (it) can make in the future. To see (following the August 1999 earthquake) these unsung, unnoticed indigenous brick-and-timber buildings standing among the ruins of the modern world around was enough to make anyone think.”

Traditional construction techniques found in earthquake zones, for example, reveal a process of Dar-winian style “adaptation”, to environmental threat. Timber-and-masonry lacing, a technique a little like the timber cross-hatching familiar from English Eliza-bethan architecture, is found throughout Turkey and the Balkans. The taq system of construction found in Northern India, uses heavy masonry walls, bonded together with large, horizontal timbers. Aspects of the vernacular architectural tradition in Nepal, are also adapted to the risk of earthquakes.

TIMBER-FRAMES IN CHINA:  Langenbach argues that such traditional buildings, widely distributed across the world and forming part of many different architectural traditions, could provide a wealth of information to present and future generations on how buildings can adapt to seismic threat and how the problem of earthquakes may be solved.

One particularly interesting example comes from China. According to Ms Zhang Zhiping, Director of the Conservation Centre for Monuments and Sites at the National Institute for Cultural Heritage in Beijing, traditional timber-framed buildings have been built in China for thousands of years. And these buildings perform excellently in earthquakes. During the 1996 earthquake in Lijiang, a UNESCO World Heritage Site, traditional buildings remained intact while more modern ones collapsed, even in the most seriously damaged areas of the town.

Patchwork Building:  One region of the world in which traditional or vernacular architecture has evolved in ways responsive to the seismic environment is Kashmir in Northern India. Here, two types of traditional brick-and-masonry construction were used until quite recently, the taq and the dhajj-dewari, both having marked anti-seismic properties. Dhajj-dewari literally means “patch-quilt wall”, and this aptly conveys the look of such buildings. Little mortar is used to bond the masonry, and it is divided by timbers into a series of discrete piers with little or no other bonding. In the taq system a similar method is used, except that both masonry and timbers are much heavier and the buildings more massive.

During earthquakes such methods have marked advantages because they give ductility to an otherwise brittle structure, allowing it to respond to seismic forces without fracturing or collapsing. According to Randolph Langenbach, the way these traditional brick-and-masonry buildings respond is significant because the form of construction used prevents destructive cracking in one part of the building and allows energy to dissipate.” A British visitor to Kashmir, Arthur Neve, noticed the superior performance of the traditional architecture compared to contemporary colonial-style buildings when he visited the area following an earthquake in 1885. Whereas the latter buildings collapsed, he wrote, “it was remarkable how few houses fell... If well built, the whole house... sways together, whereas more heavy rigid buildings split and fall.”

David Tresilian, UNESCO



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