Tibet Bridges
Bridges in Tibet exist in many forms, among which suspension bridges and string bridges represent local features to a large degree. There are two kinds of string bridges: one is rattan string bridges, the other iron string bridges. String bridges are seen mostly in the southeast of Menba area and in Luoba area. Cable crossings are used mainly in Chamdo area. Cable crossings connect both banks of a river with a cable or string. People sit on a bar with a pulley hung on to the string or cable while flying across the river. According to historical materials, many a large string bridges had been constructed over the wide Yarlung Tsangbo River in the middle of 15th century. It’s said that a great monk a monk of Ka-gyud-pa, Tangtong Jiebu, in order to build an iron string bridge over the deep gorge of Yarlung River, had raised money by organizing and performing Tibetan Drama. Then he collected designs and smelting craftsmen to build the bridge, after years of hard work, the iron string bridge was completed. The bridge became a landmark of Tibetan’s technological advancement.
Suspension bridge, also called flying bridge, tends to be built over rivers with deep water and steep banks, where is hard to build bridge foundations. For instance, a suspension bridge over the Xiangquan River, in Zhada, Ali, is 20 meters long. At either end of the bridge, a bridge seat is built which is 6 meters wide and composed of six layers of logs extending towards the center of the river. There are six logs put closely to form a layer, 1.7 meters wide. All six layers are built on stilts. Then another six logs are set side by side to cross the eight-meter-wide expansion over the river, which connects two suspensions. On each side, two stone structures with gateways were built so as to hold those logs tightly. When a bridge is built in a wide, shallow and smooth river, piers will be added. Such a suspension is really grandeur. Suspension bridges are not only a reflection of bridge experts’ understanding towards suspension, but also a reflection of certain technological achievement.