基于精细化有限元模型的混凝土框架结构动力倒塌承载力

Dynamic Collapse Load-carrying Capacity of Concrete Frame Structures Based on Refined Finite Element Model

为评估混凝土框架结构在柱子突然失效时在动力荷载作用下的承载能力,以研究团队开展的现浇(RC)和全装配式(PC1明牛腿插销节点)混凝土框架子结构中柱移除多级重复倒塌动力试验为基础,通过初级垮塌荷载工况下位移响应曲线的拟合,校核了论文中用ABAQUS软件建立的框架子结构精细有限元分析模型的准确性,并利用拆除构件法对框架结构的抗连续倒塌性能进行了损伤量化评估.由于研究团队试验是多次重复垮塌试验,无法获取RC和PC1(明牛腿插销节点)试件一次倒塌所承受的荷载,对于全装配式(PC2暗牛腿插销节点)未进行动载试验,根据准确校验模型利用试算法分别预测了RC、PC1和PC2框架结构的最终破坏荷载,并对三者的破坏模式和损伤情况进行了对比分析.破坏时,RC梁柱损伤严重,梁端钢筋拉断,装配式梁端连接区混凝土被压溃,插销杆被剪断,且现浇试件的抗倒塌能力明显高于全装配试件,此外还发现,通过加强装配式结构的角钢能提高其抗倒塌承载能力.

To evaluate the load-carrying capacity of concrete frame structures under dynamic loads in case of sudden column failure,this paper is based on the multi-stage repeated collapse dynamic tests of mid-column removal in reinforced concrete(RC)and fully assembled precast concrete(PC1 exposed corbel dowel rob nodes)concrete frame substructures carried out by the research team,the accuracy of the sub-structural detailed finite element model established by the ABAQUS software was verified by fitting the displacement response curves under primary collapse load conditions,and the damage resistance of the frame structure to progressive collapse was quantified and evaluated using the column removal method.Since the research team tests were multiple repetitive collapse tests,it was not possible to obtain the load-carrying capacity in one collapse for the RC and PC1(exposed corbel dowel rob nodes)specimens,and dynamic load tests were not conducted for the fully assembled precast concrete(PC2 hidden corbel dowel rob nodes).The final damage loads of the RC,PC1 and PC2 frame structures were predicted using the trial algorithm based on the accurate calibration model,and the failure modes and damage conditions of the three structures were compared and analyzed.During the failure,the RC beam-column was severely damaged,the rein⁃forcement at the beam end was pulled off,the concrete at the connection area of the fully assembled precast concrete beam end was crushed,and the dowel rob was sheared off.The collapse resistance of the reinforced concrete specimen was significantly higher than that of the fully assembled precast concrete specimen,and it was also found that the collapse resistance load-carrying capacity of the fully assembled precast concrete structure can be improved by strengthening the steel angle cleat of the assembled structure.