地基不均匀沉降对上部框架结构影响的静动力分析

Analysis of influence of uneven settlement of foundation on upper frame structure

地基不均匀沉降会造成上部结构产生过大变形,引起结构构件开裂、损坏。为了研究超过规范允许变形值较大的不均匀沉降变形(0.004l)情况下,原有结构在静力作用下的内力变化和在地震作用下的抗震性能水平,本文以一框架结构为算例,在地基不均匀沉降与地震作用下对结构进行静动力分析。分析结果表明地基不均匀沉降变形对局部变形较大处结构构件产生较大影响,产生较大的附加内力,叠加罕遇地震作用后,结构弹塑性层间变形相比无沉降变形结构显著增大,仍在规范允许范围内,说明大震下结构仍具备较好的整体抗震能力,在沉降变形的附加内力作用下,沉降变形较大的梁柱构件及与之相邻的构件受其影响损坏严重,通过加大构件配筋率可显著改善影响较大构件的抗震性能。

Uneven settlement of foundation may cause excessive deformation of superstructure and cause cracking and damage of structural members.In order to study the change of internal force of the original structure under the static load and the level of seismic performance under the earthquake when the non-uniform settlement deformation(0.004l)exceeds the allowable deformation,a frame structure is taken as an example in this paper,the static and dynamic analysis of the structure is carried out under the action of uneven settlement of foundation and earthquake.The results show that the non-uniform settlement deformation of foundation has a great influence on the local deformation of structural members,and produces a large additional internal force,compared with the non-settlement structure,the elastic-plastic inter-story deformation of the structure is significantly larger,and it is still within the allowable scope of the code,which shows that the structure still has a better overall seismic resistance under large earthquake,and under the additional internal force of settlement deformation,the beam-column members with larger settlement deformation and its adjacent members are seriously damaged by the influence.The seismic behavior of the members with larger settlement deformation can be improved by increasing the reinforcement ratio.