带腋撑梁式转换结构地震易损性分析

针对钢筋混凝土梁式转换结构存在竖向刚度突变不利于抗震的问题,在转换层处设置了钢筋混凝土腋撑,以降低转换结构竖向刚度突变程度,改善其抗震性能。通过对普通与带腋撑钢筋混凝土转换框架结构进行增量动力分析,建立其地震易损性曲线方程,并且研究了腋撑对钢筋混凝土转换框架结构破坏机制的影响。分析结果表明,钢筋混凝土腋撑能有效地减缓转换框架结构地震反应,显著地降低转换框架结构在各个破坏状态下的超越概率。在强烈地震作用下,钢筋混凝土腋撑能有效地避免结构在首层与转换层处形成"层侧移机构"的破坏机制,防止钢筋混凝土转换框架结构发生整体或局部倒塌破坏。

Seismic Fragility Analysis of Transfer Beam Structure with Haunch Brace

To improve the poor seismic performances of the reinforced concrete(RC) transfer beam structure with problem of vertical stiffness irregularity,RC haunch brace was proposed to be installed at the transfer story to change the vertical stiffness irregularity of RC transfer beam structure.The incremental dynamic analysis of RC transfer frame structure with and without haunch brace was carried out and the seismic fragility curve equations were established.The influences of haunch brace on failure mechanism of RC transfer frame structure were investigated.The results show that the seismic responses of the transfer frame structure can be effectively alleviated by RC haunch brace.The probability of exceedance of the transfer frame structure corresponding to different damage states can be significantly decreased.The lateral drift mechanism in the first and transfer story of the structure can be avoided effectively by haunch brace under the strong ground motions.The global and local collapse of the RC transfer frame structure can be prevented.