Optimization of Cable Force of Extradosed Bridges

Abstract

In order to solve structural optimization problems in the past, it is necessary to integrate structure analysis software and optimization software. Since structural analysis has been the only function considered when developing most of structure analysis software, they suffer from closeness of system. Therefore, it is not easy to integrate them with optimization software. This study proposes an experimental design method to solve this problem including following steps: (1) generate experimental design, (2) implement experimental design, (3) construct a response variable model, (4) define optimization problem, (5) solve optimization problem. The purpose of step (1) through step (3) is to create a response variable model of alternative structure analysis software. This model is a set of regular and simple functions, it can easily define the optimization problem in step (4), in order to facilitate step (5) to solve the optimization problem. The reason to employ neural network instead of traditional regression analysis in step (3) is that the relationship between internal forces and displaced cross section dimension of the structure are often nonlinear. Neural network is a nonlinear system that gives itself the greatest advantage to accurately construct a nonlinear model. This case study is based on optimization design of cable force and tower height in an extradosed bridge, evaluating the feasibility of above method and comparing with published references to confirm the proposed method in this study is applicable to the optimization design of extradosed bridge.