钢筋混凝土框架抗倒塌性能影响因素分析

Analysis on Factors Affecting the Capability of Collapse of Reinforced Concrete

为了研究钢筋混凝土(reinforced concrete,RC)框架结构抗倒塌性能的影响因素,首先采用两榀混凝土平面框架抗倒塌试验对ABAQUS有限元模型进行验证与校准。然后基于验证后的模型,建立15个3层4跨的混凝土平面框架进行不同层数的中柱失效、梁下部钢筋配筋率和梁上部钢筋配筋率等参数变化的抗倒塌分析。研究结果表明:失效柱所在楼层越低,悬链线效应越难发挥作用;梁下部钢筋配筋率的提高对悬链线效应没有正面影响,当配筋率过高时反而会削弱结构的悬链线效应;梁上部钢筋配筋率的提升可以显著增强结构的悬链线效应。悬链线效应阶段消耗的能量至少占倒塌全过程消耗总能量的70%,评价结构的鲁棒性时应结合悬链线效应的作用。

In order to examine on the factors to collapse resistance of the structure,the ABAQUS finite element model was firstly verified and calibrated by using the progressive collapse test results of the two-layer concrete plane frame.Then 15 three-story and four-span concrete plane frames were established to carry out the progressive collapse analysis on three parameters based on the verified model.The parameters included the failure of the middle column of the different layers,the reinforcement ratio at the bottom of the beams,and the reinforcement ratio at the top of the beams.The results showed that the lower the floor where the failure of the center column is,the more difficult the catenary action is to play a role.The improvement of the reinforcement ratio at the bottom of the beams had no positive effect on the catenary action.The catenary action of the structure was weakened when the reinforcement ratio was too high.The increase in the reinforcement ratio of the upper part of the beam could significantly enhance the catenary action of the structure.The energy dissipation at the catenary action accounted for at least 70%of the total energy dissipation during the collapse process.Thus,the contribution of the catenary action should be considered when evaluating the structural robustness.