Structural Optimization Of Extradosed Cable-Stayed Bridge

Extradosed cable-stayed bridge is a transition form in bridge structures in the development of the past decade years, which has the dual structural characteristic of cable-stayed bridge and continuous bridge’s, such system solve the problems of low utilization of beam prestressed reinforced body configuration and space-constrained.Due to superior performance of the structure, the good economic indicators, as well as architectural modeling on its unique merit, the extradosed cable-stayed bridge shown enormous development potential and is subjected to increasing attention in the bridge engineering, and obtain the rapid development in domestic and foreign countries.This article attempts to probe into the problems in the extradosed cable-stayed bridge design theory, carry on the optimization to the structure, propose the new parameter reference value, then obtain the reasonable structural style.Firstly, the article summarizes the extradosed cable-stayed bridge’s origination and present situation in the domestic and foreign development, systematic analysis of the extradosed cable-stayed structure characteristics, the superiority and its design features.Secondly, the main structural parameters of PC extradosed cable-stayed bridge are briefly summarized. Based on real bridge project, finite element model is established by Midas/Civil. Using main beam bending moment objective function, arrangement mode of cable is opitimized. Then the effects of main beam bending moment which result from length variation of non-stayed cable segment are studied. Therefore reasonable scope of its length is obtained. Based on cable force influence matrix,by means of target function of cable prestress, opitimal model is build. Then reasonable tower height is got. Therefore the height is reduced and the rate of utilization of cable reaches the highest in its range of allowable stress.Thirdly, the article takes the structural parameters of the extradosed cable-stayed bridge—the length of non-cable area and the tower height reasonable scope’s regularity initially searches, then obtaines a more satisfactory result.Finally,the article puts forward a new mentality of extradosed cable-stayed bridge design according to the research findings, and this article has the consulting value to the other similar bridges.