【摘要】 为了满足一般桥梁建设工程对50年超越概率5%(地震重现期975年)和50年超越概率2%(地震重现期2475年)下地震动加速度值的需求,该文以编制《中国地震动参数区划图》的数据为基础数据,计算了50年超越概率2%、50年超越概率5%和50年超越概率10%这3个概率水平下的谱加速度值(T=0.0s、0.2s、0.3s、1.0s),统计了50年超越概率2%谱加速度和50年超越概率5%谱加速度分别与50年超越概率10%谱加速度的比值在基岩场地和中硬场地条件下的均值及方差。结果表明:50年超越概率2%水平下的地震动加速度值与50年超越概率10%水平下的地震动加速度值之比的均值在基岩场地下为1.78~2.11,在中硬场地条件下为1.70~1.79;50年超越概率5%水平下的地震动加速度值与50年超越概率10%水平下的地震动加速度值之比的均值在基岩场地下为1.31~1.42,在中硬场地条件下为1.29~1.37。由于土层放大的非线性效应,中硬场地条件下比值的均值比基岩场地条件下稍小。利用K-S检验,发现比值可近似看成符合正态分布,因此可以使用比值的均值来换算50年超越概率2%和50年超越概率5%下的地震动加速度值。更多还原

【Abstract】 In the general bridge constructions,the ground acceleration values for 5% probability of exceedance in 50a(5% P.E.in 50a)(return period of 975 years) and 2% probability of exceedance in 50a(2% P.E.in 50a)(return period of 2475 years) are required.In this article,we use the data sets used in the "National Seismic Zoning Map of China" to calculate respectively the spectral accelerations(T=0.0s,0.2s,0.3s,1.0s) for 2% P.E.in 50a,5% P.E.in 50a and 10% P.E.in 50a.We also do the statistical analyses on the ratios(R1) of ground accelerations for 2% P.E.in 50a to ground accelerations for 10% P.E.in 50a and the ratios(R2) of ground accelerations for 5% P.E.in 50a to ground accelerations for 10% P.E.in 50a,respectively.The means of R1 vary in the ranges of 1.78~2.11 for a hard-rock site and 1.70~1.97 for a firm soil site.The means of R2 vary in the ranges of 1.31~1.42 for a hard-rock site and 1.29~1.37 for a firm soil site.These results show that the means of ratio values for the firm soil site are smaller than the ones for the hard-rock site due to the nonlinear effect of firm soil.Finally,we test the distribution of ratios by using a K-S test,and find that the distribution of ratios approximately follows the Normal Distribution at the significant level of α=0.05.Therefore,the means of ratio values(R1,R2) can be used to convert the ground accelerations for 2% P.E.in 50a and 5% P.E.in 50a,respectively.更多还原