多维地震输入下曲线匝道桥梁伸缩缝碰撞响应

Pounding response of expansion joint in a curved ramp bridge under multidimensional seismic input

针对曲线匝道桥梁伸缩缝地震碰撞破坏现象,依托某市多层互通式立交体系中一座独立、单支、多联、曲线、箱梁匝道桥,用Kelvin接触单元模拟了伸缩缝处地震和碰撞效应,建立了全桥空间动力分析模型。利用非线性时程分析法,分别输入单维(X方向、Y方向)和多维共8种地震动工况,分析了曲线匝道桥梁伸缩缝的地震碰撞响应差异。结果表明:曲线匝道桥梁由于曲率的影响,不同方向地震动响应存在耦合效应,其伸缩缝碰撞响应的最不利值应考虑多维地震输入工况,并用碰撞力和碰撞位移双指标控制伸缩缝的地震碰撞响应。

In view of the pounding damage of expansion joint in a curved bridge under earthquake,the Kelvin contact element was used to simulate the pounding between expansion joints.An independent single multi-unit long curved ramp bridge in a multilevel junction system was selected as a project example,and its space dynamic model was built.Using nonlinear time history analysis method,the different pounding responses of the bridge were analyzed under eight different types of seismic conditions those were in one-dimensional or multidimensional seismic input direction.The results show that the seismic response of a curved bridge in different directions is coupled.So the expansion joint seismic pounding response of a curved bridge should be analyzed including multidimensional seismic condition and evaluated with pounding force and pounding displacement simultaneously.