Dynamic Response of Cable-Stayed Bridge and Trains on Bridge Under Cable Breaking Conditions

In order to study the dynamic response characteristics of long-span highway-railway cable-stayed bridges with broken cables under the dynamic actions of wind and train, an actual cable-stayed bridge was taken as the research object, and a 3D computational model of the whole bridge was established. The nonlinear implicit dynamic time history algorithm was used to analyze the dynamic response of the whole bridge in the case of sudden cable breaking. The dynamic response of the bridge structure and the train running on the bridge under different sudden cable breaking conditions was studied under the coupling effect of the train and bridge. In addition, the dynamic response of the bridge structure and the train running on the bridge under the coupling effect of wind, train, and bridge was discussed when the structure was in a static equilibrium state after a few cables were broken. The nonlinear explicit dynamic time history algorithm was used to study the cable breaking and falling state under the action of lateral wind. The results show that long-span highway-railway cable-stayed bridges have high safety redundancy, and it is only possible for continuous cable breaking and collapse to occur when more than 12 longer cables of the mid-span break. When a single cable breaks, the maximum increase in dynamic stress for the remaining cables is approximately 100 MPa, which has a minor impact on the safety of the bridge structure. When a sudden cable breaking occurs while a train is running on the bridge, it will cause a noticeable change in the acceleration response of the train, or in other words, the calculated maximum acceleration under various conditions is approximately 1.5 m/s2. After the breaking of a single longest cable, the vertical displacement response of the train running on the bridge increases by less than 0.01 m, resulting in a small impact on the stiffness of the bridge, and the bridge can still accommodate train traffic. When the longest cable breaks, if the lateral wind speed reaches 30 m/s, it may cause the broken cable to fall into the upper deck lane of the girder, invading a distance of approximately 5 m, which affects the safety of traffic on the upper deck lane. © 2024 Science Press. All rights reserved.