摘要
随着GB 18036—2015《中国地震动参数区划图》中引入了极罕遇地震作用、GB/T 51408—2021《建筑隔震设计标准》中提出了基于直接设计法的隔震结构设计理念以及《基于保持建筑正常使用功能的抗震技术导则(报批稿)》中对保证结构正常使用功能提出了相应指标,有必要对基于直接设计法的基础隔震结构在设防、罕遇和极罕遇地震等多级地震作用下能否保证安全性及正常使用功能展开研究。将基础隔震结构简化为集中质量的多自由度体系并采用直接设计法完成结构设计,采用非线性时程分析方法研究上部结构自振周期、水平侧向刚度竖向分布及隔震系统力学性能参数对基础隔震结构在多级地震作用下安全性和正常使用功能的影响规律。研究结果表明:上部结构自振周期和隔震系统屈重比的变化对于基础隔震结构在设防和罕遇地震作用下的安全性及正常使用功能有较大的影响;极罕遇地震作用下基于直接设计法的基础隔震结构基本能够满足保证结构安全性的要求,但是同等条件下增大上部结构自振周期、减小隔震系统周期和屈重比均会对保证结构安全性带来不利影响;在隔震层与基坑挡墙发生碰撞的情况下基础隔震结构将难以保证安全性和正常使用功能,因此为有效降低基础隔震结构在极罕遇地震作用下与周边基坑挡墙发生碰撞,同时也避免过大的隔离空间,建议隔离缝的宽度取为罕遇地震作用下隔震层水平变形值的两倍。
With the introduction of extremely rare earthquakes into GB 10836—2015“Seismic ground motion parameters zonation map of China”,the direct design method proposed in the GB/T 51408—2021“Standard for seismic isolation design of building”,and some performance indices related to functionality of structures proposed in“Guideline for seismic technology to maintain functionality of buildings in earthquakes(draft for approval)”,it is necessary to investigate whether base-isolated structures based on the direct design method could guarantee the safety and function requirements under multi-level earthquakes(i.e.,design based earthquake,maximum considered earthquake and extremely rare earthquake).In this study,a direct design-compliant base-isolated structure was modelled as a multiple degree of freedom of system with lumped masses.Through parametric studies,the effects of the natural vibration period of the superstructure,the distribution of lateral stiffness and the parameters of the isolation system on the safety and function of base-isolated structures were studied.The results show that the natural vibration period of the superstructure and the yield-weight ratio of the isolation system have a great influence on the safety and function of base-isolated structures.Under the extremely rare earthquake,the base-isolated structure can basically ensure safety.However,uniform lateral stiffness distribution,long natural period of superstructure,short period and small yield-weight ratio of isolation system will be unfavorable to structural safety.Considering the pounding of the structure with surrounding retaining wall,the safety and normal use function of the base-isolated structure will be difficult to ensure.Therefore,it is recommended that the width of the seismic gap should be twice as much as the horizontal deformation of the isolation system subjected to the maximum considered earthquake.
作者
王昱翔
叶昆
WANG Yuxiang;YE Kun(School of Civil and Hydraulic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2023年第11期1-14,共14页
Journal of Building Structures
基金
国家自然科学基金项目(52078234)。
关键词
基础隔震结构
铅芯橡胶隔震支座
直接设计法
多级地震作用
抗震性能
碰撞
base-isolated structure
lead rubber bearing
direct design method
multi-level seismic action
seismic performance
pounding
