Main Cable Shape of Short Span in Three-Tower Suspension Bridge

Abstract

The main cable is one of the essential components of the suspension bridge; accurate calculation of the main cable shape is crucial in constructing a suspension bridge. This paper solves the challenge of the main cable shape for a “short span” in a three-tower suspension bridge by the analytical method of the ideal bridge shape and empty cable shape of the main cable. Feng Chu suspension bridge Xiangyang is taken as a prototype. This paper discusses the main cable shape and anchor-span tension control method in the construction stage of the main cable analyzes the deflection and stress characteristics of the main tower in the hoisting stage of the stiffening beam. The influence of pushing the cable saddle on the main tower provides accurate control of the main cable shape. Design sag and span of the main cable were taken as the known quantities. The sectional catenary equation is used to deduce and iteratively calculate the completed bridge alignment. The completed bridge alignment was taken as the target, the iterative calculation method of main cable bridge alignment and empty cable alignment compiles the corresponding program with MATLAB software. The calculation values of the unstressed length of the main cable, the pre-deflection of the saddle, and the mid-span sag of the empty cable are compared with the design values. The results show that the calculation accuracy of the program is high.