Computer control system for steel tower segment fabrication of Nanjing 3rd Yangtze River Bridge

Nanjing Yangtze River 3rd bridge is the first bridge that used the steel structure as the main tower in China. Because of the big size, the steel tower had to be divided to 22 segments in factory and erected segment by segment at bridge site. The shape of the steel tower can not be adjusted during erection and the fabrication error of each segment will be accumulated and propagated during erection. Accordingly, high fabrication precision of each segment was required. A variety of computer control techniques including computer aided axes determination technique, mechanical cutting platform with computer controlled reactions and 3-D shape simulation technique were used in Segment fabrication. The system has been applied successfully to the construction of Nanjing 3rd Yangtze River Bridge. In this paper, we gave the introduction of the system.