基于一致危险性谱的砌体结构抗震性能分析

Seismic Performance Analysis of Masonry Structures based on Uniform Hazard Spectrum

地震危险性分析和地震动选择对结构抗震设计具有重要作用。一致危险性谱作为概率地震危险性分析的重要结果,通常会被用来做目标谱以选择地震动记录。为改善概率地震危险性分析对震源传播特性考虑的不足,基于随机有限断层模拟与概率地震危险性分析相结合的方法,充分考虑震源机制、传播路径和场地放大效应的影响,结合目标场地条件对历史地震进行模拟,生成了同一超越概率下的一致危险性谱。分别以一致危险性谱和规范谱为目标谱,各选择7条地震波,对一典型砌体结构进行动力时程分析。结果表明:以不同目标谱选择地震动对结构的动力响应差别较大,合理选择目标谱是十分有必要的;一致危险性谱在短周期内谱值较高,以其为目标谱使得短周期结构动力响应较大,可为结构抗震设计提供参考。

Seismic hazard analysis and ground motion selection play an important role in seismic design of structures.As an important result of probabilistic seismic hazard analysis,the uniform hazard spectrum is usually used as a target spectrum to select ground motion records.In order to improve the deficiency of probabilistic seismic hazard analysis on source propagation characteristics,this paper presented a combination method based on stochastic finite fault simulation and probabilistic seismic hazard analysis.The influence of the hypocenter mechanism,seismic propagation path and site amplification effect was fully considered in the method.The historical earthquakes were simulated in combination with the target site conditions,and the uniform hazard spectrum under the same probability was generated.Selecting the uniform hazard spectrum and standard spectrum as the target spectrum,the dynamic time history analysis of a typical masonry structure was carried out by using seven input seismic waves.The results show that the ground motion obtained by different target spectra has a great influence on the dynamic response of the structures,indicating the importance of rational target spectra selection.The uniform hazard spectrum has a high spectral value in the short period.Taking it as the target spectrum makes the short period dynamic response of the structure larger,which can provide references for the seismic design of structures.