不同地震动特性下RC框架校舍抗震加固残余变形分析

Residual deformation analysis of a seismically reinforced RC frame school building subjected to earthquakes with different characteristics

校舍的抗震性能和震后残余变形直接关系到学生的顺利疏散和学校的震后修复,因此,本文以RC框架校舍为背景对其不同地震动特性下的抗震性能和震后残余变形展开研究。首先,介绍了泰州市姜堰区实验小学敏学楼的工程概况和加固方案,并据此建立了结构三维有限元模型,开展了动力特性分析;随后,进行多遇地震作用下的弹性和设防/罕遇地震作用下的弹塑性时程分析,并以层间位移角为性能指标对结构抗震性能水平进行了评估;最后,以层间残余位移角和顶点残余位移为指标对比分析了近、远场地震作用下的结构残余变形。研究结果表明,近场地震作用下的抗震性能水平和残余变形指标均差于远场地震作用下的结果,其中底层层间残余位移角为远场地震的1.67倍;加固后结构在罕遇地震作用下的破坏模式由严重破坏降低到了不严重破坏,层间最大残余位移角最大降低了69.9%,校舍逃生概率和震后恢复能力显著提升。

The seismic performance and residual deformation of the school buildings influence both the smooth evacuation of the students and the post-earthquake rehabilitation of the school. Therefore,this paper focuses on the seismic performance and post-earthquake residual deformation of an RC frame school building subjected to earthquakes with different characteristsics. Firstly,the description and reinforcement scheme of the Minxue school building of the Jiangyan Experimental Primary School in Taizhou are presented,and a threedimensional finite element model of the structure is established,then the dynamic characteristics are analyzed. Secondly,the elastic time history analysis under the frequent earthquakes and the elastic-plastic time history analysis under the fortification and rare earthquakes are carried out,and the inter-story drift ratios are used to evaluate the seismic performance level of the structure. Finally,the residual deformation of the structure under near-field and far-field earthquakes are compared by using the inter-story residual drifts and the top residual displacement. The results show that not only the seismic performance level but also the residual deformation index under near-field earthquake are much worse than those under far-field earthquake,and the residual drift ratio of the bottom story is1. 67 times as much as that under far-field earthquake. The failure mode of the reinforced structure under rare earthquake is reduced from severe damage to moderate damage. The maximum residual drift angle is decreased by 69. 9%,and the escape probability and post-earthquake recovery ability of the school building are improved significantly.