Investigation on the Maximum Expansion Length of Urban Rail Transit Double-Tower Cable-Stayed Bridges Without Rail Expansion Device

Abstract

Cable-stayed bridges carrying urban rail transit are often equipped with rail expansion devices (REDs) to avoid possible breaking or buckling of the rails. Such devices not only increase construction and maintenance budgets of the track system, but also endanger ride comfort and safety of the trains. Therefore, the maximum expansion length of cable-stayed bridges without the adoption of RED is investigated and presented in this paper. Finite element models of cable-stayed bridges with various lengths are developed based on design parameters of existing bridges with similar lengths. A friction-spring model is utilized to simulate the nonlinear resistance history of fasteners under various loading cases. Track–bridge interactions are then studied by varying the longitudinal restraint conditions for the cable-stayed bridges. The investigation reveals that the admissible overall rail stress allows a maximum expansion length of about 400[Formula: see text]m for urban rail transit double-tower cable-stayed bridge paved with the ballastless track and WJ-2 small resistance fasteners. This finding provides theoretical bases and practical guidelines for the saving of REDs for many large-span urban rail transit bridges in future design.