Seismic Analysis of Long-Span Cable-Stayed Bridges by an Integrated Finite Strip Method

Abstract

This paper provides a very efficient, integrated framework for seismic analyses of long-span cable-stayed bridges. The efficiency comes from the dramatic reduction in formation time and the degrees of freedom (DOF) associated with the structure, using the integrated finite strip method (IFSM) along with the application of a very robust and efficient time history method (THM) using the Newmark scheme for dynamic analysis of the bridge structure. The previous versions of the finite strip method are limited to modeling the bridge deck only, whereas other structural components are replaced by assumed boundary conditions. Using the IFSM, all components of the long-span cable-stayed bridge can be modeled in a unified system, and consequently, the real dynamic behavior including the interactions between deck, piers, and cables can be perfectly considered. To verify the solution, the geometric and dynamic properties of the Kap Shui Mun (KSM) Bridge, as a real example of a long-span cable-stayed bridge, are derived by the proposed finite strip method. Then, the seismic response of KSM Bridge under uniform and nonuniform earthquake loadings is investigated by using the THM. The results show that the IFSM can be applied successfully for seismic analysis of long-span cable-stayed bridges, and the analysis can be performed in a minimal amount of time.