考虑台地效应的泸定6.8级地震某框架结构震害调查与分析  

Seismic damage investigation and analysis of frame structures in Luding M_s6.8 earthquake considering platform effect

作　　者：潘毅[1,2] 任靖哲 任宇 赵靖轩 巴振宁[4] Pan Yi;Ren Jingzhe;Ren Yu;Zhao Jingxuan;Ba Zhenning(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Key Laboratory of Seismic Engineering of Sichuan Province,Southwest Jiaotong University,Chengdu 610031,China;CITIC General Institute of Architectural Design and Research Co.,Ltd.,Wuhan 430014,China;Tianjin University,Tianjin 300350,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]西南交通大学抗震工程技术四川省重点实验室,四川成都610031 [3]中信建筑设计研究总院有限公司,湖北武汉430014 [4]天津大学,天津300350

出　　处：《土木工程学报》2024年第6期136-151,共16页China Civil Engineering Journal

基　　金：国家自然科学基金(52278534);四川省自然科学基金(2022NSFSC0423)。

摘　　要：2022年9月5日四川省泸定县发生6.8级地震,在磨西台地上某框架结构的震害调查中,发现其东区和西区的框架结构出现不同程度的震害,且差异明显。其中,东、西区框架的首层柱上端均发生了“强梁弱柱”型破坏,西区框架中等及以上破坏等级的比例达到81%,而东区框架仅为13%,呈现出与台地边缘的强关联性。为分析东、西区框架结构震害差异的原因,采用FK-SEM方法分析了磨西台地的地震放大效应。计算结果表明,距离台地边缘越近,地震放大系数越大。其中,水平和竖向的地震放大系数在西区建筑场地分别为2.30和2.25,而在东区建筑场地则分别为2.01和1.99。在此基础上,采用磨西台站的地震动记录,对东、西区框架结构进行了震害模拟,分析了其破坏原因。研究结果表明:磨西台地边缘的地震影响系数的实际放大系数超过了《抗规》规定,存在不利地段影响和近场地震效应叠加的情况,仅按《抗规》不利地段进行考虑,多层框架结构难以实现“大震不倒”的设防目标;竖向地震作用是框架柱下端破坏的直接原因,主要破坏形态为偏拉、偏压破坏,水平地震作用导致其二次破坏;“仿雀替”构造对结构整体变形能力不利,是框架结构“强梁弱柱”型破坏的主要原因。根据震害调查和分析结果,建议在9度近断层设防地区,靠近台地边缘的多层框架结构,设计前宜对建筑场地进行分析,并考虑竖向地震的影响;在有民族特色的建筑设计中,应将“仿雀替”等装饰物与框架脱离,设计为非结构构件,以减少其对框架结构抗震性能的不利影响。On September 5,2022,anMs6.8 earthquake occurred in Luding County,Sichuan Province.In the seismic damage investigation of a frame structure on the Moxi platform,it was found that the east and west frames experienced varying degrees of seismic damage.All the upper of the frame columns appeared “ strong beam-weak column” type failure.The proportion of the failure levels of medium or above in the west frames accounts for 81%,while the proportion of the east frames is only 13%,showing a strong correlation with the platform edge.To analyze the reasons of seismic damage differences between east and west frames,the FK-SEM method was used to analyze the seismic amplification effect of the Moxi platform.The calculation results indicate that the closer to the edge of the platform,the greater the seismic amplification factor is.The horizontal and vertical seismic amplification factors are 2.30 and 2.25 for the west frames,while 2.01 and 1.99 for the east frames.Based on the platform effect and the ground motion records of Moxi station,seismic damage simulations were conducted on the east and west frames,and the reasons for structural failure were analyzed.The results indicate that the actual amplification factor of the seismic impact coefficient on the edge of the Moxi platform exceeds that in the Code for Seismic Design of Buildings,exhibiting a superposition of unfavorable areas effect and near-field seismic effect.It is difficult to achieve the seismic fortification goal of “not collapsing during a major earthquake” when designing multi-story frame structures in unfavorable areas.Vertical earthquake is the direct cause of the damage of the bottom of the frame columns with the main forms of tensile and compressive failure,while horizontal earthquake mainly causes secondary damage.The imitated Queti structures are unfavorable for structural deformation and is the main reason for the “strong beam weak column” type failure of frame structures.Based on the investigation and analysis results of seismic damage,it is

关 键 词：泸定地震 震害调查 台地效应 震害模拟 框架结构 竖向地震 

分 类 号：TU375.4[建筑科学—结构工程] TU242.5