Research on Mechanical Performance of In-Service Continuous Rigid-Frame Bridge Based on Vehicle-Bridge Coupling Vibration

Based on a damaged continuous rigid-frame bridge in Shaanxi Province, this study deduced the crack damage simulation algorithm and the vehicle-bridge coupling numerical algorithm. Then, it established a finite element analysis model using ANSYS APDL. The Newmark-beta iterative method was used to study the dynamic response of different speeds, vehicle weights, and damage degrees before and after the structural damage. In the analysis of the influence of different speeds, the results showed that the dynamic stress responses of key sections of the undamaged bridge reached the maximum when the speed was 80 km/h, indicating that the undamaged bridge was sensitive to a speed of 80 km/h. The peak response of the damaged bridge was 90 km/h. In addition, the displacement peaks and the stress peaks rose and fell together. The analysis of different vehicle weights and damage degrees showed that with the increase in them, the displacement and impact coefficients of each section increased significantly. It can be concluded that the dynamic performance of the in-service bridge decreases continuously with the aggravation of the damage. Therefore, the influence of vehicle-bridge coupling should be emphasized in maintenance, and the frequent cracking area at the midspan should be strengthened in time to prevent further damage.