Ultimate behavior of steel cable-stayed bridges - I. Rational ultimate analysis method -

Abstract

This paper presents an investigation on the ultimate behavior of steel cable-stayed bridges. In general, various nonlinear factors affect the global behavior of cable-stayed bridges, such as material nonlinearities, cable-sag effect, beam-column effect, large displacement effect, and girder-mast-cable interaction. These effects also affect the ultimate behavior of cable-stayed bridges. Therefore, a rational analysis method should be performed to study the ultimate behavior of cable-stayed bridges. Because of various nonlinearities, the analysis should be based on the theory of nonlinear finite element analysis. Moreover, rational ultimate analysis can reflect characteristics of the design and construction of cable-stayed bridges. In this study, a rational ultimate analysis method for steel cable-stayed bridges is developed and proposed based on the theory of nonlinear finite element analysis. A two-step analysis method is proposed and used in this study. Through this analysis scheme, the structural state under dead load is considered before the live load analysis. The developed program is used to study the ultimate behavior of steel cable-stayed bridges under vertically applied live load cases. Analytical study is used to investigate governing ultimate modes under the considered live load cases. By comparing the analysis results under each live load case, the critical load case is determined. The effects of geometric nonlinearities and material nonlinearities on the ultimate behavior of steel cable-stayed bridges are studied by performing geometric nonlinear analysis, as well as ultimate analysis.