The picture above is the main arch of Xiangxi Yangtze River Bridge in Zigui County on May 22.Xinhua Press reported.(photographer: Lei Yong)

　　(Correspondents: Zheng Jiayu, Zhou Huashan, Xiang Hongmei; Reporter: Mei Yunxiong)On May 22, the main arch of Xiangxi Yangtze River Bridge in Zigui County was successfully completed, which marked the completion of the key and difficult construction task of the whole bridge project.

　　Xiangxi Yangtze River Highway Bridge is one of the major projects for the follow-up work of the three gorges migration. The length of the bridge is 883.2 meters, the main span is 531.2 meters, and the bridge surface is 32.3 meters wide, featuring atwo-way four-lane highway bridgecrossing the river.

　　The project group consists of "five bridges and one tunnel", among which the construction of Xiangxi Yangtze River Bridge is the most difficult and technically the most complex control project.The bridge is the world's largest long-span steel box truss thrust arch bridge, without piers. It is impossibleto form the main archas both sides are cliffsand it lacks supportive points.Fault ageshave been strengthened in construction and a series of quarantine measureshave been adopted to avoid rock mass damage-A national patent has been applied forthe measures.

　　The main arch of the bridge is composed of 23 curved steel trusses in the air. The construction process is like building blocks. Fourtechnological innovations have been made during the construction: slope stability and karst comprehensive remediation technology under complex geological conditions; research and construction technology of the buckle system of large-span steel box truss arches;standardization research and construction technology of large-scale cable cranes;installation and linear control of large-span steel box truss arches technology.

　　The construction of the bridge strictly adhered to the environment-friendly concept of eco-first. They attach great importance to the work of environmental protection and soil and water conservation, and invite the Environmental Protection Department and Water Conservation Department to make implementation plans. They promotethe design of spoil areaand reduce the land expropriation of itthrough measures such as "reasonable planning, multiple utilization and reduction of waste". More than 80% of construction waste is recycled, and 1 million cubic meters of waste is reused. They protect the geology by using slide-resistant pile and rock mass separation technology, and restore thesurface and ecology of destructed buildings, which truly make the Xiangxi Yangtze River Highway Bridgea "green bridge “in three gorgesarea.