LIGHTWEIGHT STONE ARCH BRIDGE IN HUNAN, CHINA

This paper describes the light stone arch bridge at Lusi Bay, China, and illustrates the achievements of this type of bridge in Hunan province. Lusi Bay Bridge is located in a well-known scenic area at Chanjiajie city, Hunan. It is an example of a new type of ribbed-slab stone arch bridge, developed in the 1980s, which inherits the old custom of using local materials with simple construction procedures, while saving up to a third of masonry by volume. Over 200 bridges of this type have been constructed so far, with spans up to 120m. The 381m long, 21m wide bridge has six main spans, each of which is 48m long and has span-rise ratio 8. The bridge crosses a river with a flood plain. The river bed bottom is covered with 5-7m of sand gravel, lying on top of red sandstone and conglomerate strata. Because of high flood risks, large diameter cast in-situ pile foundations were used. The construction techniques for the main arches and spandrels are outlined. During the last five years, six static loading tests of light stone bridges with different characteristics have been conducted, to study why they have high potential loading capacity. The plane-hinged arch effect and coalition effect contribute significantly to this.