土与结构相互作用对层间隔震结构影响的参数分析

RELATED PARAMETER ANALYSIS OF STORY ISOLATION STRUCTURE CONSIDERING SOIL-STRUCTURE INTERACTION

层间隔震结构是在基础隔震结构的基础上发展起来的一种新型隔震结构体系。实际工程中,因受到地形条件和建筑功能使用需求的限制,仅能在中间某层设置隔震装置,从而形成层间隔震体系。层间隔震体系在减震机理、振动特性及设计方法等方面均有别于基础隔震结构。通过有限元分析,研究了土-结构相互作用(SSI)对层间隔震结构地震响应的影响,探讨场地土弹簧刚度,隔震层水平刚度等参数变化时,考虑SSI作用下层间隔震结构地震响应的变化规律。研究表明:SSI效应使得层间隔震结构刚度弱化,引起其周期延长,土越软地震效应越大;SSI效应对层间隔震结构的地震响应,如体系的基底剪力、顶层位移、层间位移、层间剪力等,均造成不同程度的影响,土越软效果越明显;隔震层水平刚度对体系地震响应也存在一定影响。

Mid-story isolation structure is a new type of isolating system based on the base isolation structure. In practical engineering application,because of the special terrain conditions and the need for the use of architectural features,which would require setting the isolation unit in the middle layer to form a story isolating system. Story isolation system is different from base-isolations in the damping mechanism of shock damping system,vibration characteristics and design methods etc. The finite element analysis software was also used to analyze how the system seismic responses change when changing the soil stiffness and the isolator＇s stiffness after taking account of the soilstructure interaction. The results showed that because of decreasing the stiffness of the story isolation system,SSI effects prolong the structure＇s fundamental period,and the softer the soil was,the larger the amplitude was; SSI would influence the structure＇s seismic response,such as the base shear,top floor displacement,story drift and story shear of the system,and the softer the soil,the more obvious effects; the horizontal stiffness of the isolation unit also had a certain influence on the system dynamic response.