Coupled Vibration Analysis of Earthquake-Wind-Vehicle-Bridge for Long-Span Bridges Considering Scouring Effect

In order to study the influence of the scouring effect on the dynamic response of long-span bridges under the combined action of earthquake and wind, based on the established coupled vibration analysis model of earthquake-wind-vehicle-bridge, the p-y curve ( p is the soil resistance and y is the pile displacement) reduction method was used to consider the load-displacement relationship between the piles and soil with different scour depths, and the lateral support stiffness and length of pile foundation were updated according to the load-displacement relationship and scour depth. Thus, the influence of the scouring effect on the dynamic response of long-span bridges was considered, and the model was applied to analyze the scouring effect of Jiangshun Bridge. The results show that the foundation scour weakens the lateral constraint of the foundation soil on the structure, thus reducing the natural vibration frequency of the structure, and the maximum reduction of the natural vibration frequency of lateral vibration mode is 6.01%; under the action of the operational vehicle and wind load, foundation scour has little effect on the vibration response of the structure; after the earthquake, the foundation scour increases the lateral vibration of the structure, and the maximum increase in the extreme value of the lateral displacement response of the structure is 9.1%; the lateral displacement response spectrum increases accordingly, but it has little effect on the vertical vibration of the structure; foundation scour may reduce the response of lateral acceleration of vehicles, and the maximum reduction of the extreme value of the lateral vehicle acceleration response is 7.7%, but it has little effect on the vertical vibration of vehicles.