竖向地震引起的城市高架桥的车‒桥耦合作用

Vertical Earthquake Shaking Induced Vehicle-Bridge Coupling Behavior of Urban Viaducts

摘要:

建立了典型城市高架桥的车?桥耦合作用简化模型，利用非线性接触单元模拟桥面和车辆之间的耦合，并选取不同频谱特性的竖向地震动作为激励，研究汽车质量、频率、地震动频谱特性和峰值加速度等多个参数对车?桥耦合系统动力响应的影响。结果表明，车辆质量和车辆振动频率以及地震动频谱特性均对车桥耦合系统有较大的影响，在共计1 866个工况中有221个工况出现了车桥分离的现象；车桥分离对桥梁竖向位移响应多表现为不利，同时还大幅增加了车辆对桥面的碰撞力；在统计意义上，车桥分离的峰值加速度的平均值随着汽车质量的增加而增加，随着汽车频率的增加而减小，随着地震动平均周期的增大而减小。

Abstract:

This paper established a simplified vehicle-bridge coupling model of urban viaduct via nonlinear contact element to simulate the contact relationship between vehicle tires and bridge deck， and to investigate the influence of vehicle mass， frequency， ground motion spectrum characteristics and peak acceleration on the dynamic response of vehicle-bridge system subjected to selected vertical ground motions with wide-range of spectral characteristics. The results show that the vehicle mass， vehicle vibration frequency， and ground motion spectrum have a great influence on the vehicle bridge coupling system. The vehicle bridge separation phenomenon occurs in 221 of 1 866 cases. Vehicle bridge separation is unfavorable to the displacement response of the bridge in most cases， and also greatly increases the impact force on the bridge deck. Statistically， the average value of peak acceleration of vehicle bridge separation increases with the increase of vehicle mass， decreases with the increase of vehicle frequency， and decreases with the increase of average period of ground motion.