RC框架子结构连续倒塌动力响应分析

Analysis of Dynamic Response of Progressive Collapse for RC Frame Substructure

采用ABAQUS有限元软件的Explicit和Standard模块分别对RC梁柱子结构中柱失效的动力试验和静力试验进行了数值模拟,验证了模型的正确性,并在原动力试验的基础上做了进一步的计算,分析了中柱失效时间和梁上荷载值对剩余结构动力响应的影响。为得到该动力试验试件在不同静力荷载下的中柱位移,对该试件采用静力方式进行了加载,通过动力位移与静力位移的比值得到动力放大系数,随后讨论了失效时间和荷载大小对动力放大系数的影响。结果表明:失效时间越短,中柱的最大竖向位移和振幅越大,且动力放大系数随着失效时间的增大而减小;梁上荷载越大,中柱节点的最大竖向位移越大,当荷载大于某一临界值时,位移将随时间持续发散增长,该临界点的荷载值可称作剩余结构的动态极限承载力;剩余结构的动态极限承载力随着中柱失效时间的增大有所增加;梁上荷载对动力放大系数值影响较小。

Numerical simulation analyses for dynamic test and static test of reinforced concrete beam-column substructures were conducted using Explicit and Standard modules of ABAQUS finite element software, respectively, and the correctness of the model was verified. Then, based on the original dynamic test, further calculations were carried out to analyze the influence of failure time of middle column and load on beam on the dynamic response of the residual structure. In order to obtain the displacement of middle column under different static loads, the dynamic test specimen was also loaded with static load, so the dynamic increase factor could be obtained, which equaled to the ratio of dynamic displacement to static displacement, then the effect of failure time and load value on the dynamic increase factor was discussed. The results show that when the failure time gets shorter, the maximum vertical displacement and amplitude of middle column will get larger;the dynamic increase factor decreases with increase of failure time. The maximum displacement of middle column increases as the load on beam increases, when the load exceeds a certain value, the displacement will continue to divergence with time, this critical load can be called dynamic ultimate bearing capacity of the residual structure, according to analysis, the ultimate bearing capacity of the residual structure increases with the increase of failure time of middle column;the load on beam has little influence on dynamic increase factor.