The origin and development of“ Zuo Bridges”

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The origin and development of" Zuo Bridges

Based on an anlaysis of historical documents and extensive personal investigation, this paperexplores the origin and development of" Zuo Bridges" in the minority nationality region in SouthwestChina. A discussion was also made of their influence on modern bridge construction. Because of thecomplicated and perilous environment in the area ,special technique was needed to make bridges to crossgorges and rivers , and therefore rope ways were first developed for this purpose, including single ropeways and double rope ways. However , rope ways could not satisfy the traffic necessity due to their un-safety and low. bearing capacity. Therefore , several ropes were used together to create a simple bridge ,such as Dangdian and rattan net bridge. The improvement of such simple bridages resulted in Zuobridges. Zuo bridges had the fundamental features of chain and suspension bridges , which were consid-ered as the results of the further improvement of Zuo bridges.