基底摇摆隔震桥墩振动台试验与数值模拟研究

Shaking table test and numerical simulation study on base rocking isolation bridge piers

为了研究不同构造形式的基底摇摆隔震桥墩在不同水准地震作用下的响应规律和抗震性能,提出了设置高阻尼橡胶垫块和线性弹簧的两种基底摇摆隔震桥墩模型。通过振动台试验和数值模拟,对两种摇摆隔震桥墩的地震响应规律和抗震性能进行了对比研究。结果表明:两种基底摇摆隔震桥墩在不同水准地震作用后,桥墩均没有出现严重的破坏,其破坏特征主要表现为限位钢板的弯曲变形和提离约束部件的移位,桥墩呈现出良好的抗震性能;两种基底摇摆隔震桥墩相对于传统桥墩能够显著降低墩顶加速度和墩底应变响应,但墩顶水平位移响应也会相应增加,在摇摆隔震桥墩的设计上,应将墩顶水平位移作为主要设计参数;提出了两种基底摇摆隔震桥墩改进的Winkler两弹簧数值计算模型,通过与振动台试验结果对比,证明了该模型能够较好地模拟两种基底摇摆隔震桥墩的摇摆行为及其地震响应规律。

In order to explore the seismic response rules and the seismic performance of base rocking isolation bridge piers with different structure details under different levels of seismic actions,two new models of base rocking isolation bridge piers were proposed in this paper. The seismic response rules and the seismic performance of the two proposed rocking isolation bridge piers were investigated by means of shaking table test and numerical simulation. The experimental results show that the base rocking isolation bridge piers have no serious failure and damage. The bending deformation of restrictor steel plates and the sliding of lift-restraint members are the main failure characteristics under different levels of seismic actions,indicating a good seismic performace. Compared with traditional bridge piers,the base rocking isolation bridge piers could significantly reduce the horizontal acceleration at the top of the pier and the strain response at the bottom of the pier. However,the horizontal displacement at the top of the pier could be increased accordingly. Therefore,the horizontal displacement at the top of the pier should be considerd as the main design parameter in the design of base rocking isolation bridge piers. The modified Winkler two-spring models were proposed to simulate the seismic response of base rocking isolation bridge piers. By comparing with the results of the shaking table test,the proposed calculated models can simulate the rocking behaviours and seismic response rules of the two base rocking isolation bridge piers.