考虑悬链线效应的钢筋混凝土框架结构抗连续倒塌能力分析

Progressive collapse capacity analysis of reinforced concrete frame structures considering catenary action

为了研究悬链线效应对钢筋混凝土(RC)框架结构抗连续倒塌能力的影响,基于OpenSees建立可以考虑悬链线效应的RC框架宏模型,通过两个RC框架子结构在移除中柱后的竖向承载力试验结果对比,验证了所采用宏模型的合理性,并研究了悬链线效应对RC框架子结构抗连续倒塌能力的影响。分别采用备用荷载路径法中的非线性静力方法和非线性动力方法对1栋10层RC框架结构进行抗连续倒塌能力分析,研究悬链线效应对RC框架整体结构抗连续倒塌能力的影响。结果表明:不考虑悬链线效应的影响将低估RC框架结构的抗连续倒塌能力;在移除底层中柱情况下,不考虑悬链线效应分析得到的荷载放大系数最大值小于2.0,而考虑悬链线效应分析得到的荷载放大系数最大值则超过2.0。

The effects of catenary action on reinforced concrete （RC） frame structures to resist progressive collapse were investigated. An OpenSees-based macro-model considering the catenary action was developed. The macro-model was validated by comparing the simulated results with the test results of two RC beam-column substructures, which were subjected to the loss of a middle column scenario. Moreover, the effects of catenary action on the response of a ten-story RC frame structure to resist progressive collapse were examined by both nonlinear static and nonlinear dynamic analyses from the alternative path method. The results show that if ignoring the catenary action, the progressive collapse capacity of RC frame structures will be underestimated. When the catenary action is not considered, the calculated maximum load increase factor for the frame subjected to the loss of the middle column of the first story is less than 2.0, while it is beyond 2.0 with considering the catenary action.