Structural Stability of Cable-stayed Bridges during Construction

This paper presents an investigation of the stability characteristics of steel cable-stayed bridges during construction. In general, cable-stayed bridges are subjected to quite large compressive forces induced by stayed cables, and may become unstable during their construction stage, due to the excessive compressive forces induced by added construction loads. To solve the structural instability problems of the bridges under construction, a nonlinear analysis program was developed based on the theory of nonlinear finite element analysis. The complex stability characteristics of cable-stayed bridges during construction were investigated through a series of rigorous geometric nonlinear analyses, including various structural nonlinearities such as cable-sag effect, beam-column effect of girder and mast, large displacement effect, and girder-mast-cable interaction. To consider the construction characteristics of the cable-stayed bridges, a three-step analysis method is proposed, and used in the present study. In addition, the effects of various cable-arrangement types and girder-mast stiffness ratios on the stability characteristics were extensively investigated. Typical buckling modes can be classified into two categories, depending on the location of critical member or members.