不同设计基准期下地震动峰值加速度取值分析

Analysis of Value Selection for Peak Ground Motion Acceleration in Different Design Reference Period

为了得到大跨度桥梁抗震设计中采用高于抗震规范设计基准期时的地震动参数,通过烈度建立设计基准期与地震动峰值加速度之间的联系,运用经验公式分析了不同设计基准期下地震动对峰值加速度的表现规律,并与现有抗震设计规范就设计基准期为50年概率水平下的取值做了对比分析,通过实桥的地震安全性评价数据验证了该方法在设计基准期为100年概率水平下计算结果的可靠性。

In order to obtain the values of ground motion parameters that are higher than the values in the design reference period stipulated in the seismic specifications for the seismic design of long span bridges, the correlation between the design reference period and the peak ground mo- tion acceleration was established based on seismic intensity, and the performance pattern of peak ground motion acceleration in different design reference period was analyzed via empirical formu-la, and the results of the analysis were compared with the values drawn in accordance with the probability level of a 50-year design reference period in the current seismic design specifications. In addition, on the basis of the seismic safety evaluation data of actual bridges, the reliability of the calculated results of probability level of a lO0-year design reference period obtained by this method was verified.