Dynamic Stress Analysis of Coupled Vehicle-Suspension Bridge System in Cross Wind

Dynamic stress computation of long suspension bridges under both railway and wind loading is required for either strength or fatigue assessment. However, the effect of dynamic coupling among bridge, railway vehicle and wind on bridge stress response is not well understood. This paper presents a method for predicting bridge dynamic stress responses with coupling effects included. The bridge model (bridge subsystem) and vehicle model (vehicle subsystem) are established using the finite element method, and they are related to each other through wheel-rail contact conditions. The spatial distribution of both buffeting forces and self-excited forces over the bridge deck surface is considered to facilitate the computation of local stress responses. The Tsing Ma suspension bridge in Hong Kong and the data recorded by a Wind and Structural Health Monitoring System (WASHMS) installed in the bridge are utilized as a case study to verify the proposed method to some extent. The railway loading and wind speed measured by the WASHMS are taken as input for the computation simulation. The computed local stress responses are compared with the measured ones. The results from the case study demonstrate that the proposed method could effectively predict the local stress responses of the coupled traffic vehicles and suspension bridge system in cross winds.