基于IDA和易损性分析的RC框架结构底层柱端弯矩增大系数

为研究RC框架底层柱上下端弯矩增大系数的合理取值与该系数取值的合理性,设计6栋具有不同柱端弯矩增大系数、不同设防烈度的框架结构进行增量动力分析,输入10条地震波,得到各结构模型的IDA曲线。在此基础上,通过定义不同的烈度水平,得到各结构的易损性曲线与倒塌破坏概率。结果表明:按照现行规范设计的7度设防与8度设防框架可以满足大震不倒的设防要求;若将梁柱节点与底层柱下端弯矩增大系数的取值分别提升至1.5与1.8,可使框架在特大地震作用下发生倒塌的概率降低至可接受范围之内。

Research on bottom column end moment amplification factor of RC frame based on incremental dynamic analysis and fragility analysis

In order to study the reasonable value of the bottom column end moment amplification factor of the RC frame structure and the rationality of the value of this factor according to the current codes, six RC frame structure models were designed with various column end moment amplification factors and fortification intensity.The models were analyzed based on incremental dynamic analysis by inputting 10 seismic waves to obtain the IDA curves of the structures. On the basis of the IDA, different intensity levels were defined, and the fragility curves and the failure probability of collapse of each structure were obtained. The results shows that the RC frame structure at 7 or 8 degree fortification in accordance with the current codes can satisfy the fortification reqirements for "No Collapsing in the Strong Earthquake"; when the values of column end moment amplification factor and the beam column joint are raised to 1.5 and 1.7 respectively, the probability of collapse under the large earthquakes will be acceptable.