高墩大跨连续刚构桥梁IDA分析结果离散原因
The cause of the discreteness of IDA analysis results for high pier and long span continuous rigid frame bridge

为研究地震动特性对高墩大跨桥梁IDA分析结果离散性的影响，以某一高墩大跨铁路桥梁为工程依托，基于OpenSEES建立其非线性有限元模型；采用“谱兼容”的方法从太平洋地震中心的PEER数据库选择20条地震记录，对该算例桥梁进行IDA分析，研究地震动的峰值、反应谱幅值 和 等参数对结果离散性的影响。研究结果表明：高墩大跨桥梁的IDA分析结果的离散性是由于桥梁第1阶模态对应的谱加速度 的离散导致的，二者存在明显的正相关关系，在高墩大跨桥梁增量动力分析选择地震波时严格控制 的离散性，有利于提高高墩大跨桥梁非线性地震反应分析结果的精确性。
In order to study the effect of ground motion characteristics on the nonlinear seismic response of long-span and high pier bridge, a high-pier and long-span rigid frame bridge was taken as an example, and corresponding nonlinear dynamic model was established based on OPENSEES finite element software. After that 20 seismic records were selected from the PEER database based on “spectrum compatibility” method. Increment dynamic analysis was carried out, and the correspondence between long-span and high pier bridge nonlinear seismic response and ground motion characteristics parameters was analysed. The results indicate that the discreteness of IDA analysis result of long-span and high-pier bridge is caused by the discreteness of the spectral acceleration corresponding to its first mode. They have obviously positive correlations. Keeping tight control over the discreteness of spectral acceleration corresponding to its first mode will improve the accuracy of nonlinear seismic response analysis when increment dynamic analysis is carried out