文章摘要

文章信息/Info

Title:: Risk Analysis of the Bridge Hit by the Mainshock-aftershock Sequence Considering Fault Distance

作者:: 李喜梅¹; 2; 苏润田¹; 2; 李明睿¹; 2; 母渤海³; (1.兰州理工大学西部土木工程防灾减灾教育部工程研究中心,甘肃兰州 730050; 2.兰州理工大学防震减灾研究所,甘肃兰州 730050; 3.中国市政工程西北设计研究院有限公司,甘肃兰州 730050)

Author(s):: LI Ximei¹; 2; SU Runtian¹; 2; LI Mingrui¹; 2; MU Bohai³; (1.Disaster Prevention and Mitigation Engineering Research Center of Western Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,Gansu,China)(2.Institute of Earthquake Protection and Disaster Mitigation,Lanzhou University of Technology,Lanzhou 730050,Gansu,China)(3.China Municipal Engineering Northwest Design & Research Institute Co., Ltd.,Lanzhou 730050,Gansu,China)

Keywords:: the Luding M_S6.8 earthquake; strong motion records; response spectrum; attenuation relation

摘要:: 为了提高震害预测和结构震后性能评估的准确性和合理性,提出了一种考虑断层距衰减的主余震序列构造方法,并使用该方法构造了50组相关场地的地震动; 以一座三跨连续梁桥为研究对象,使用OpenSees抗震分析软件进行非线性动力分析,采用改进的Park-Ang损伤指标建立易损性曲线,分析断层距对连续梁桥在不同设防主余震序列下的损伤指数和破坏概率的影响; 提出震后危险性分析方法,对比分析了考虑断层距的主余震序列对桥梁结构的震后风险性影响。结果表明:余震的发生导致结构的损伤概率提高了10倍以上; 在断层距10 km范围内的结构发生中度及以上破坏的风险性较大; 提高设防地震等级能有效避免结构在主余震序列作用下发生严重或倒塌破坏; 在震后救援和重建时考虑断层距的影响可以防止造成二次伤害。

Abstract:: To improve the accuracy and rationality of the seismic damage prediction and estimation of the post-earthquake structural performance,a mainshock-aftershock construction method considering the fault distance attenuation is proposed,and 50 sets of the ground motion are constructed using this method.A three-span,continuous beam bridge is selected as the sample.Nonlinear dynamic analysis is carried out using OpenSees software,and an improved Park-Ang damage index is used to establish the vulnerability curve.The influence of the fault distance on the damage index and failure probability of the continuous beam bridge at different fortification levels when hit by the mainshock-aftershock sequence is analyzed.A post-earthquake risk analysis method is proposed,and the impact of the mainshock-aftershock sequence on the seismic risk of bridge structures considering fault distance is compared and analyzed.The results show that the probability of structural damage increases tenfold with the occurrence of aftershocks.The risk of moderate or higher damage to structures within a fault distance of 10 km is relatively high.Increasing the aseismic fortification level can effectively prevent structures from serious or total collapse under the action of the main aftershock.The fault distance plays an important role in preventing the secondary damage in the post-earthquake rescue and reconstruction.