Vehicle-Bridge Coupled Vibration Analysis Of Highway Cable-Stayed Bridges

Highway cable-stayed bridges belong to the cable supported bridges with weak stiffness,in recent years, with the development of economic, technology and material, many complex light-weight highway cable-stayed bridges were built. The structural properties of the bridges are complex, it is difficult that to use the pseudo-static method to measure the dynamic performance with vehicle loads, the spans are often less than 100m, so little attentions were paid to that; and the girder's frequency is close to the heavy load's, it may make sympathetic vibration. The xiaoxin bridge is the representative.This paper firstly discuss the Simulation method of the cable, girder and tower, use the spatial grillage model to simulate the whole and local vibrations of girder , and the model was checked through dynamic test data. Analyze the nature vibration of vehicles, road roughness, the vehicle initial vibration before the bridge, and accurately simulate the interaction during coupling vibration of vehicles-bridges.Then modify the separated iterative method, to use the computing model with outer iteration loop and inner time loop. Use the ANSYS software's time history analysis to solute the vibration of the bridge, and simulate the road surface roughness, calculate interaction force to achieve the vibration analysis of vehicles with MATLAB software. Use the measured deflection curve, to verify the simulation results of bridge dynamic response. Investigate the influence of the vehicle speed, road roughness, the cross-beam effect, dynamic stiffness and local factors. Found that the excessive vibration of the bridge was induced by the lower dampers and the closure of the bridge natural frequency and the vehicle's.Finally, use the MTMD dampers to induce the excessive vibration, the result show that the vibration peak was lower and the free vibration was fast weakened.