基于PSHA计算方法的豫南地区桥梁设计地震动参数研究

摘要

According to anti-seismic design criterion for bridges and roads in China, the designed ground motion parameters of bridge design is determined by the probability level of reproduction period T=475 years and 2000 years, probabilistic seismic hazard analysis ( PSHA) is often used for calculating bedrock peak gravity acceleration ( PGA) in similar project. This paper studied a bridge in southern Henan area to calculate the seismic hazard of ground motion parameters. Results show: At the probability reproduction period of T=100 years, 475 years and 2000 years, the bed rock PGA is respectively 12. 7, 31. 6 and 72. 5 gal; corresponding to horizontal designed ground motion PGA of respectively 19. 3 , 45. 7 and 98. 7gal. The studied zone is at 0. 05G zone in 5th generation China Ground Motion Parameters Map, the authors suggests the designed basic PGA be 50gal, which is coherent with calculation results.%根据我国路桥抗震设计规范,桥梁工程设计地震动参数以重现期T=475年和2000年的概率水准确定,地震危险性概率分析方法(PSHA)常用于计算此类工程的基岩峰值加速度(PGA).以豫南地区某桥梁为研究对象,对地震动参数进行概率危险性计算.结果表明:该桥在重现期T=100、475和2000年概率水准下的基岩峰值加速度分别为12.7、31.6和72.5 gal;对应水平向设计地震动峰值加速度分别为19.3、45.7和98.7 gal.研究区位于第5代中国地震动参数区划图0.05 g区,建议设计基本峰值加速度为50 gal,其与计算结果较为一致.