既有结构增设早屈型抗侧力分支体系的性能分析

Performance Analysis of the Existing Structure with Additional Early Yield-type Side Force Resistant System

为准确预测增设抗侧力分支体系的既有结构在真实地震下的动力响应,实现基于性能的抗震设计方法,有必要研究分支体系强度不足而过早屈服对结构地震响应的影响。本文采用等效简化的研究方法,对增设分支体系的既有结构进行了特定烈度地震动力时程分析,研究了分支体系早屈对结构地震响应的影响。结果表明:分支体系早屈的前提下,长周期范围内结构的最大相对位移和原结构承担的地震作用幅值,随分支体系屈服强度系数的降低呈递减趋势。在短周期范围内,结构的最大相对位移和原结构承担的地震作用幅值随分支体系屈服强度系数的降低呈递增趋势。

The accurate prediction of the real dynamic response under earthquake of the existing structures with additional branch system of side force resistant is necessary for the performance-based seismic design method of structures. The affect of insufficient strength of the branch system on structural earthquake response is studied. Research methods of simplified equivalent are used based on time- history analysis under speaific intensity to study the infulenee of early yielding of the branch system on structural earthquake response. The results show that, with long periods, maximum relative displacement of structure and maximum earthquake undertaked by the original structure will be reduced by decreasing branch system yield strength coefficient after branch system yielded. Reversely, with short periods, maximum relative displacement of structure and maximum earthquake undertaked by the original structure will be increased by decreasing branch system yield strength coefficient.