Study On Spatial Main Cable Construction Control Of Long-span Self-anchored Suspension Bridge

The self-anchored suspension bridge with spatial cable system is different from traditional suspension bridge, it has the traits with self-anchored and spatial loads. So the nonlinear influences were represented extraordinary during the construction phases. Based on self-anchored suspension bridge in tunnel construction of YANGZI River, analysis on the construction control of main cable is completed, the detail as the following:1. The paper summarizes some nonlinear factors of self-anchored suspension bridge and geometrical nonlinearity analytical methods, discusses several commonly nonlinear equation calculated methods.2. Based on calculation theory of plane main cable shape, according to the assumption of cable element, the cable calculation equations of 2D are deduced. Then the cable calculation equations of 2D are transformed into the cable calculation equations of 3D. This article made a research on the cable curve and computational method of self-anchored suspension bridge, introduced an iteration method of spatial cable shape on the basis of calculation method for spatial cable proposed by Ohstuski. According to the mechanical characteristics of the single-tower self-anchored suspension bridge, based on the initial and fine balance analysis, iterative correction balance analysis is proposed to consider the change of cable shape and internal forces caused by the compression of the main tower and the main beam.3. Based on calculation formula of combined arc saddle's position, a reliable and accurate correction method to calculate the point of contact between spatial cable and saddle and the position of cable saddle are derived from mechanical relationship and geometrical relationship.4. Researching the method of pre-displacement of saddle, strand construction controlling and calculating the construction shape of the catwalk for the bridge.5. Taking the Jiangxinzhou self-anchored suspension bridge for example, creating a three-dimension finite element model of whole bridge using universal finite element procedure MIDAS/CIVIL and ANSYS, and make a nonlinear static analysis. The different between cable shape and internal force under calculating result and finished state are compared. Using supposition, calculation, comparison and rectifying supposition, which can get the main cable shape and the coordination of each cope satisfied with the designed shape.