结构动力时程分析的地震动选择方法研究

进行结构动力时程分析时,合理地选择地震动一直是工程中的难点问题.为此,通过改进现有的和声搜索法进行地震动的选取,针对依据我国现规范设计的两榀不同周期的预应力混凝土(PC)框架结构进行了动力时程分析,并与周期点法、双频段法和面积法的计算结果进行对比.分析表明:多遇地震作用下,周期点法和改进的和声搜索法的结构响应参数的离散性更小,其变异系数在10%左右,且与振型分解反应谱法得到的底部剪力相比,双频段法和改进的和声搜索法得到的计算结果更加符合规范设计水准;罕遇地震作用下,面积法和改进的和声搜索法的结构响应参数的离散性更小,其变异系数在15%左右,周期点法计算结果离散性最大;周期点法只适用于弹性时程分析的地震动选择过程,改进的和声搜索法无论是对弹性时程分析还是弹塑性时程分析都适用,且满足规范设计水准和工程需求.

Research on Ground Motion Selection Method for Time-history Analysis of Structure

In the process of structural dynamic time-history analysis, reasonable ground motion selection is always a difficult point in engineering. By improving the existing harmony search method for ground motion selection, dynamic time-history analysis is performed for two differently periodic prestressed concrete (PC) frame structures designed according to currently Chinese codes. Then, it is compared with the periodic point method, the dual-band method and the area method for calculation results. The results show that the discreteness of structural response parameters of the periodic point method and the improved harmony search method is smaller in frequently earthquake, and the coefficient of variation is about 10%. Compared with the base shear force of mode-superposition response spectrum method, the dual-band method and the improved harmony search method are more in accordance with the standard design. Structural response parameters of the area method and the improved harmony search method are smaller dispersion in rarely earthquake, and the coefficient of variation is about 15%. Furthermore, the results of the periodic point method are the most dispersion. The periodic point method is only applicable to the ground motion selection process of elastic time-history analysis. The improved harmony search method is applicable to both elastic and elastic-plastic time-history analysis, which can meet standard design and engineering requirement.