【作者】 朱瑞广；

【导师】 吕大刚；

【作者基本信息】 哈尔滨工业大学 ， 岩土工程， 2011， 硕士

【摘要】 对缺乏真实地震动记录地区进行地震危险性研究和地震动选择,对结构抗震设计有重要的参考作用。一致危险性反应谱是概率地震危险性分析的重要拓展,通常会被用来做目标谱以选择地震动记录;条件均值谱则能够在以感兴趣的基本周期所对应的谱加速度发生为条件,提供一条期望的反应谱,它是一种有效选择地震动记录的工具。本文以美国中部Memphis TN地区为研究目标,对该区内1000年可能发生的地震进行模拟。基于该地区的地震发生的概率、震级分布以及震源位置等统计资料,对Memphis TN地区周围1000年内可能发生的地震进行模拟,分别建立了点源模型和随机有限断层模型,并产生对应不同震源模型的人工地震加速度时程和伪加速度反应谱。其中,点源模型采用SMSIM中AB95_BC模型,随机有限断层模型则采用增加标准化因子的改进模型。通过对人工模拟地震动进行统计,建立其对数正态统计模型,并对其进行假设检验,得到基本周期为0.1s和1.0s的地震危险性曲线,并获得50年超越概率为10%和2%的一致危险性谱,并建立50年超越概率为2%的一直危险性谱对应的条件均值谱。最后,将目标谱由一致危险性谱转化为模拟谱,并借助贪心优化技术,从已有地震动数据库中选择10条与条件均值谱相容的地震动记录。研究表明:基于条件均值谱的地震动选择方法,所选地震动记录样本的均值和方差与目标谱较为一致。进一步经过贪心优化技术处理,可使新的地震动样本的形状和目标谱更为接近。更多还原

【Abstract】 The study on seismic hazard analysis and record selection in the buildings site without enough earthquake record data is very important to the seismic design of structures. As an important extension of probabilistic seismic hazard analysis (PSHA), the uniform hazard spectrum (UHS) is usually used as a target spectrum to select earthquake records. While the conditional mean spectrum (CMS) can provide the expected resonse sepectrum conditioned on occurrence of a target spectral accelation value at the period of interest, so it is another useful fool for selecting ground motions.In this thesis, the city Memphis TN in the USA is selected as a site location of interest to simulate the earthquakes that may occure in the future 1000 years. Based on the rate of occurrence, the distribution of magnitude, the location of focus, all the earthquakes that may occure near Memphis TN in 1000 years are simulated. The point source model and stochastic finite fault model are buillt, and the acceleration time history and pseudo-spectral acceleration spectrum are generated respectively. The point source model is AB95_BC model of the program SMSIM (3.1), while the stochastic finite fault model is a modified one with a normalized factor. All the records are analyzed with statistical methods using lognormal distribution in hypothesis testing. The curves of seismic hazard at T=0.1 & T=1.0s and UHSs with exceedance probability of 2% & 10% in 50 years are obtained, while the CMS corresponding to the UHS with exceedance probability of 2% & 10% in 50 years are also derived. Finally, the target spectrum is transformed from UHS to CMS, and 10 records which are compatible with CMS are selected from the database with a greed optimization technique.It is demonstrated in this thesis that the mean and standard deviation of the samples which are selected based on CMS are consistent with the target spectrum, and that the shapes of new samples which are dealt with the greed optimization technique are more consistent with the target spectrum.更多还原