远场长周期地震下层间隔震结构的非线性减震分析  

Mitigation of nonlinear responses of mid-story isolation structures subjected to far-field long-period ground motions

作　　者：颜桂云 方艺文 吴应雄[2] YAN Guiyun;FANG Yiwen;WU Yingxiong(Fujian Provincial Key laboratory of Advanced Technology and Information in Civil Engineering,School of Civil Engineering,Fujian University of technology,Fuzhou 350118,China;School of Civil Engineering,Fuzhou University,Fuzhou 350116,China)

机构地区：[1]福建省土木工程新技术与信息化重点实验室,福建工程学院土木工程学院,福州350118 [2]福州大学土木工程学院,福州350116

出　　处：《振动与冲击》2018年第4期208-218,共11页Journal of Vibration and Shock

基　　金：国家自然科学基金(51778149)；福建省教育厅项目(JA15324)；福建省自然科学基金项目(2015J01182)

摘　　要：远场长周期地震动具有长持时、低频成份丰富等特征,部分地震动后期振动阶段产生多个循环脉冲,类似谐和振动;其可能对隔震建筑等长周期结构的抗震性能带来不利影响,需深入探讨。首先讨论远场长周期地震动的运动特征。然后以8条远场长周期地震与3条普通地震记录作为地震动输入,对一幢钢筋混凝土框架层间隔震结构进行了非线性地震反应分析。探讨地震波中的长周期成份,尤其类谐和成份对隔震结构减震性能的影响。提出在隔震层增设黏滞阻尼器,形成组合隔震方案;分析其对隔震层的限位保护效果与对隔震结构的非线性减震效果。结果表明:远场长周期地震作用下层间隔震结构的减震效果相比普通地震作用下的减震效果变差。特别在远场类谐和罕遇地震作用下,层间隔震结构的非线性响应相比抗震结构几乎无减小,甚至显著放大;隔震支座最大位移远超越其允许位移。组合隔震能较有效地控制远场长周期地震、特别是远场类谐和地震作用下隔震结构的非线性反应,尤其可显著减小隔震支座的最大位移,防止隔震支座破坏。Far-field long-period ground motions were featured by long duration and rich low frequency components.Particularly,multiple cycle pulses similar to harmonic vibration were generated at the late stage of some seismic waves.These may cause adverse influence on the seismic performance of the long-period structures including the isolation building,which needs to be investigated deeply.To this end,the characteristics of far-field long-period ground motions were discussed.Then,six far-field long-period earthquake records and three common earthquake records were selected as the input of ground motions,and the seismic responses of a RC mid-story isolated frame structures were obtained by nonlinear analysis.Also,the impact of the long-period components of seismic waves,especially harmonic-like components on shock absorption performance,was investigated.Further,a combined isolation scheme by the addition of viscous dampers in the isolation layer was proposed,and its effects on limiting deformation of the isolation layer and reducing nonlinear responses were explored.The results show that the effectiveness of the mid-story isolation subjected to far-field long-period ground motions on reducing nonlinear seismic responses is not as good as those subjected to common ground motions.Particularly,the nonlinear responses of the mid-story isolated structure are seldom reduced or significantly enlarged under the far-field harmonic-like strong ground motions compared with those of the seismic structure,and the maximum displacement of isolation bearings is far beyond the allowable displacement.It is also indicated that the combined isolation can effectively control nonlinear responses of the mid-story isolated structure under far-field long-period ground motions,especially harmonic-like ground motions.In particular,the maximum displacement of the isolation bearings can be significantly decreased,preventing the destruction of the isolation bearing.

关 键 词：远场长周期地震 层间隔震结构 组合隔震 非线性反应 隔震层限位 

分 类 号：TU352.1[建筑科学—结构工程]