考虑SSI效应的框架结构体系动力响应分析  

Dynamic Response of Frame Structure System Considering SSI Effect

作　　者：李培振[1] 肖嘉取 杨金平 丁永刚[2] LI Peizhen;XIAO Jiaqu;YANG Jinping;DING Yonggang(State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;College of Civil Engineering,Henan University of Technology,Zhengzhou 450001,Henan,China)

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092 [2]河南工业大学土木工程学院,河南郑州450001

出　　处：《华南理工大学学报（自然科学版）》2023年第9期139-148,共10页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51978524,52108134)。

摘　　要：为了研究软土地基上考虑土-结构相互作用(SSI)对高层结构动力响应的影响机理,文中设计了1:6比例的框架结构模型,分别进行了考虑结构-桩-土动力相互作用和刚性地基上框架结构的振动台试验。通过对比考虑SSI的框架模型和刚性地基框架模型的结构动力响应,总结出本试验中SSI效应对高层纯框架结构的影响规律:考虑SSI效应后,桩-土相互作用对地震波具有明显的过滤作用,大震时一般有削弱峰值的作用,且整体结构的振动频率降低,阻尼比提高。从结构内力来看,SSI效应减小了楼层剪力和弯矩,有效降低了地震动对结构的影响。从结构位移看,当震级较小时,SSI效应减小了结构的弹性位移和层间位移角,降低了地震对结构的作用;当震级较大时,上部楼层由于模型差异和损伤累积,部分工况下SSI效应增大了结构位移响应。从结构加速度看,SSI效应降低了楼层绝对加速度和相对加速度,同样减小了地震对结构的作用。这是由于SSI效应下桩-土相互作用产生辐射阻尼和滞回阻尼,消散了整个结构-桩-土系统的能量,同时软土地基传递给上部结构的辐射波改变了结构的动力特性。A 1∶6 ratio frame structure model was designed for shaking table test,in order to study the influence mechanism of soil-structure interaction on the dynamic displacement response of high-rise structures on soft soil foundation.Shaking table tests were performed on a high-rise frame structure considering soil-pile-structure dynamic interaction system and on a frame structure model on fixed-base condition.By comparing the structural dynamic response of the frame models considering the soil-structure interaction(SSI)and the fixed-base condition,the influence of the SSI effect on the high-level frame structure in this experiment was summarized:after considering the SSI effect,pilesoil interaction has an obvious filtering effect on seismic waves;in a large earthquake,the peak is generally weakened,and the vibration frequency of the overall structure is reduced,and the damping ratio is increased.From the perspective of structural internal forces,the SSI effect reduces the floor shear force and bending moment,and effectively reduces the impact of ground vibration on the structure.From the perspective of structural displacement,when the magnitude is small,the SSI effect reduces the elastic displacement and interlayer displacement angle of the structure,and reduces the effect of the earthquake on the structure;when the magnitude is larger,the upper floor increases the structural displacement response due to model differences and damage accumulation under some working conditions.From the perspective of structural acceleration,the SSI effect reduces the absolute acceleration and relative acceleration of the floor,and also reduces the effect of earthquakes on the structure.This is due to the radiation damping and hysteresis damping generated by soil-pile-structure interaction under the SSI effect dissipate the energy of the entire structure-pilesoil system,while the radiation waves transmitted by the soft soil foundation to the superstructure change the dynamic characteristics of the structure.

关 键 词：土-结构相互作用 动力响应 振动台试验 高层结构 软土地基 

分 类 号：TU318.4[建筑科学—结构工程]