隔震曲线梁桥不同等级地震的振动特性模拟分析

Simulation Analysis of Vibration Characteristics of Isolated Curved Girder Bridges under Different Earthquakes

曲线桥梁抗震特性模拟分析对于曲线桥梁隔震、减震有着重要意义。基于隔震曲线桥梁设计过程中的特点,通过非线性水平弹簧单元对铅芯橡胶支座双向非线性的能力进行模拟,根据SAP2000科学选择强震观测地震波,并考量曲线桥梁本身存在的特性对桥梁振动特性产生的影响,针对隔震曲线桥梁在不同等级地震下振动特征进行模拟分析,其中,通过隔震曲线桥梁铅芯橡胶支座模型的构建和梁桥不同等级地震计算模型、输入地震波与传感器量测等步骤得到的模拟结果为:不同地震波与加速度峰值输入过程中,地震动较小下的支座水平刚度比较大,且结构相对稳定;地震幅值增大时,桥梁支座水平刚度减小,且支座的恢复力位移滞回变化曲线面积比较大,能够更多地将地震输入能量消散掉,减小能量不断向曲线桥梁上方传递的速度,可有效减轻地震反应,起到隔震的效果。

The simulation analysis of the seismic characteristics of curved bridges is of great significance to the isolation and damping of curved bridges.Based on the design characteristics of isolated curved bridges,a nonlinear horizontal spring unit was used to simulate the bidirectional nonlinearity of the lead rubber bearing.Using SAP2000,a strong earthquake was selected,and the characteristics of the curved bridge were considered.The vibration characteristics of the bridge were simulated and analyzed considering different earthquakes.The simulation results are as follows:In the inputting process of different seismic waves and peak accelerations,under small earthquakes,the horizontal stiffness of bearing was relatively large,and the structure was relatively stable;the horizontal stiffness of the bearing under large earthquakes was relatively small,and the restoring force-displacement hysteresis curve of the bearing was relatively large,which can dissipate the seismic input energy,thus effectively mitigating the seismic response and play the isolation effect.