Optimum Design of Stay Cables of Steel Cable-stayed Bridges Using Nonlinear Inelastic Analysis and Genetic Algorithm

Abstract

This paper presents an effective method to optimize stay cables of steel cable-stayed bridges using nonlinear inelastic analysis and a micro-genetic algorithm (μGA). The innovation of the proposed procedure is that both initial cable tensions and total weight of the cables are optimized. In order to calculate the optimum initial cable tensions, a new μGA-based method using a unit load matrix is proposed, which allows a significant reduction of computational effort. The cable cross-sections are then optimized subject to dead and live loads using nonlinear inelastic analysis. To estimate nonlinear inelastic behaviors of the bridge such as cable sag influence, large displacement, and second-order effect, a practical advanced analysis (PAA) based on catenary elements for cables and plastic-hinge beam-column elements for pylons, girders, and cross beams is used. The capabilities of the proposed method are illustrated by studying semi-harp and harp types of a steel cable-stayed bridge.