摘要
场地土层条件及地震动频谱特性对地震中结构响应及其震害具有显著影响,而现阶段结构易损性分析多未考虑场地条件以及地震动特性的作用。根据地震动频谱特性参数,即峰值位移与峰值加速度比值(Rd2a),将输入地震动分为4组;同时,基于场地土层平均剪切波速将场地分为基岩、硬场地、中硬场地和软场地等4类。采用OpenSees软件,建立坐落于单一土层场地上的6层钢筋混凝土(RC)框架结构概化模型。在不同场地条件下输入不同分组地震动,采用增量动力分析法(IDA)分别计算结构响应及结构破坏状态,探讨地震动特性和场地条件对结构易损性的影响规律。结果显示:①不同分组地震动输入下结构的易损性曲线差别显著,Rd2a值越大结构破坏的概率越大;②场地条件对结构易损性曲线存在一定的影响,该影响与结构的破坏状态相关,即结构破坏状态越严重,越硬场地的破坏概率趋于增大;③相对于地震动特性对结构易损性的影响,场地条件的影响较小;④在结构的易损性分析中既要考虑场地条件的影响也要考虑地震动特性的影响,特别是输入地震动的选取,对结构易损性分析结果影响较大。通过简化模型评价场地条件和地震动特性对结构易损性的影响,以期为结构易损性评价以及震害预测提供参考。
Site conditions and ground-motion frequency characteristics play a significant role in structural response and seismic damage distribution.However,the current structure fragility analysis techniques have hardly considered such effects.Taking the ratio of peak displacement to peak acceleration(i.e.,Rd2a)as an index,the ground-motion records collected are subdivided into four groups.Meanwhile,based on the site average shear-wave velocity(Vs),the site conditions are classified into four categories which are bedrock,hard site,medium-hard site,and soft site.Using the OpenSees software,a simplified model for a six-story reinforced concrete(RC)frame structure on a single soil-layer site is built.The effects of ground-motion characteristics and site conditions on the fragility curves of structures for different structure damage stages controlled by the maximum structural inter-story drift angles are investigated using the incremental dynamic analysis methods.The analytical results indicate that:(1)The frequency characteristics of ground-motion greatly impact the fragility curves of structures,that is,the probability of structural damage under ground-motion loading of large Rd2a values stays higher than that of small Rd2a values.(2)The site conditions,nevertheless,impose definite influences on the structural fragility curves.Such influences correlate with the structural damage states,e.g.,when the structure is seriously damaged,the possibility of structure damage tends to increase with the increasing stiffness of sites.(3)The site conditions maintain relatively smaller influences on the structure fragility curves than the ground-motion frequency characteristics.(4)The influences of the ground-motion characteristics and site conditions should be necessarily considered in the structure fragility analysis,especially during selecting input ground-motion.The investigation of the influences of the site conditions and ground motion characteristics on structural fragility herein by a simplified model provides a reference for the structure fragility analysis and seismic damage prediction techniques.
作者
费扬
陈龙伟
FEI Yang;CHEN Longwei(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Disaster Mitigation,Ministry of Emergency Management,Harbin 150080,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2023年第S02期220-228,共9页
Chinese Journal of Geotechnical Engineering
基金
中国地震局工程力学研究所基本科研业务费专项资助项目(2021EEEVL0104)
国家重点研发计划项目(2018YFC1504004)。
关键词
RC框架结构
易损性分析
峰值比
场地条件
简化模型
RC frame structure
fragility analysis
peak ratio
site condition
simplified model