摘要
结合简化阻抗法建立了三维相互作用结构的动力有限元分析模型,导出了考虑群桩刚体、惯性效应作用时的结构相互作用时程积分方程式,以近乎纯结构有限元的建模途径合理地反映出桩-土-上部结构在水平地震作用下的动力相互作用特性。模型中引入具有桩(筏)-土阻抗特性的弹阻单元来描述不同群桩布置、土层状况因素对体系反应的参与作用,而在动力方程中竖向SV剪切波经桩土刚体相互作用产生的水平、摇摆分量对体系的影响亦得以体现。20层桩承刚框架结构的动力分析表明:较柔的桩、土基础使得体系的SSI效应增强,但其参与程度与群桩效应相关,而结构构件内力较不考虑相互作用时有较大折减;应用该法可精确、快速地进行复杂上、下部结构时程反应分析。
A dynamic FE 3D structural interaction model and the corresponding time-history equation considering kinematic interaction,inertail interaction of pile-groups are presented with the combination of simplified impedance method. The dynamic characteristics of pile-soil-structures under horizontal seismic loads are rationally reflected by means of similar pure structural finite-element approach. The participation effect on system response of different pile collocation, soil condition is described with spring -dashpot elements characterized by pile-group/raft dynamic impedance in the model. The sway-rocking input components of shear s-wave of pile-group kinematic interaction are also introduced to dynamic equilibrium equation. With the analysis for a pile-supported 20-storey steel frame, it is indicated that the SSI effect would increase with the decrease of pile/soil foundation stiffness depending on pile-group dynamic effect and the internal forces of structural, members under SSI would reduce greatly relative to fixed-base condition. The time-history response for the complicated PGSS will be accurately and quickly developed by this model.
出处
《计算力学学报》
CAS
CSCD
北大核心
2007年第6期756-762,共7页
Chinese Journal of Computational Mechanics
基金
国家自然科学基金(50278033)
教育部科学技术研究重点项目(03122)资助项目
