Structural Reliability Assessment of Long-Span Cable-Stayed Bridges Subjected to Cable Loss

This paper presents a reliability-based framework for dynamic analysis of long-span cable-stayed bridges (LSCSBs) subjected to cable breakage incidents with simultaneous presence of dynamic excitations from wind and traffic. Through the Latin Hypercube sampling technique, a series of simulation models are generated considering various sources of uncertainties stemmed from structural material properties, sectional properties, wind, vehicle composition, and cable breakage characteristics. The present study establishes the nonlinear fully coupled dynamic equations of the bridge-traffic system using the stochastic finite element approach, in which the dynamic coupling effects among bridge, wind and stochastic traffic are appropriately incorporated. Various sources of geometric and material nonlinearities are considered when cable breakage scenarios are investigated with realistic dynamic initial states. The failure probability of the bridge structure corresponding to strength and service limit states in a cable breakage event can be further obtained. After the proposed reliability framework is introduced, a prototype LSCSB is selected for a demonstration and some observations are discussed.