地震功率谱参数的误差源及其敏感性分析

Error source of seismic parameters of PSD model and its sensitivity

摘要:

为分析功率谱模型参数的误差来源及其对多点地震动和大跨桥梁结构反应的敏感性,简要回顾了规范反应谱求解地震动目标频谱参数的两种方法,开发了求解频谱参数的可视化程序TJU.SPSP,并计算出具体参数,指出求解方法不同而导致参数间误差的根本来源；更新了多点地震动模拟程序MEMS_b至新版本,总结了地震动能量与场地类型、功率谱模型之间的关系.研究结果验证了直接法和积分法对幅值及主频带宽影响的不容忽视性,强调了功率谱模型中描述低频分量参数的重要性且不应忽略,澄清了功率谱模型中阻尼比及二层过滤阻尼比的物理和数学意义,并以实际桥梁工程为例从结构地震反应角度验证了理论分析的正确性.

Abstract:

In order to analyze the error source of seismic parameters of PSD model and its sensitivity influence on ground varying motions and seismic response of long-span Bridge, two methods (direct and integral method)that usually used to solve the parameters in target PSD model according to CRS are briefly reviewed. Then, a visualization program named TJU.SPSP was developed and the main parameter values of PSD were listed in fixed format. Base on the results, the fundamental error source that caused by different methods were analyzed obviously. Moreover, the program for multi-point earthquake motions simulation (MEMS_b) was updated and the relationship between earthquake-induced ground motion energy and site soil type were summarized. The results indicate that the two methods have significant influence on the amplitude and band width of dominant frequency. The parameters describing the low-frequency component in PSD models are important and can't be ignored. Furthermore, the physical and mathematical significance of damping ratio in PSD models were clarified. Finally the validity of the theoretical analysis was verified by analyzing the seismic responses of a real long-span bridge.