考虑钢筋桁架楼承板的钢管混凝土框架抗连续倒塌性能

Progressive collapse resistance of the frame with concrete-filled steel tubular columns and steel bar truss slabs

利用ABAQUS/Explicit对边柱移除工况下钢管混凝土柱-钢梁-钢筋桁架楼承板体系的抗连续倒塌性能进行研究。在确定材性选择、损伤定义以及建模方法的准确性的基础上,分析模型的竖向承载力与破坏模式、楼承板混凝土损伤云图、关键钢构件轴向应力,探究体系内梁柱的传力规律,并量化地分析主梁抗弯机制、主梁悬链线机制、楼承板机制所提供的竖向抗力。结果表明:在边柱移除工况下,钢管混凝土柱-钢梁-钢筋桁架楼承板体系表现了较好的抗连续倒塌能力;楼承板混凝土受拉损伤和钢筋桁架拉应力主要集中在上表面的负弯矩区和下表面的正弯矩区;镀锌钢底板拉应力和梁柱约束反力占比的变化过程侧面反映了抗力由破坏位置向非破坏位置传递的机制;加载前期G6主梁的压拱效应强于G1、G2主梁,但由于边柱失效工况的边界条件对G6梁的拉结较差,在加载中后期G6梁无法充分发挥悬链线作用;加载初始主梁抗弯机制和楼承板机制提供主要抗力,而当竖向承载力达到最大值时,主梁抗弯机制、主梁悬链线机制、楼承板机制抗力占比分别为42.7%、23.8%、33.5%。钢筋桁架楼承板对框架抗连续倒塌能力的贡献是不可忽略的,始终占总承载力的30%左右。

In this paper,the progressive collapse resistance of concrete-filled steel tubular column-steel beam-steel bar truss slab system under side-column removal scenario was investigated by ABAQUS/Explicit.Based on the accuracy of material selection,damage definition and modeling method,the vertical bearing capacity and failure modes,damage nephograms of slab concrete,axial stress of key steel members were analyzed.Then the law of beam and column transmission in the system was investigated.The vertical resistance provided by the flexural mechanism and catenary mechanism of grider and the slab mechanism was analyzed quantitatively.The results show that the concrete-filled steel tubular column-steel beam-steel bar truss slab system shows a good progressive collapse resistance under side-column removal scenario.The tensile damage of slab concrete and the tensile stress of steel truss are mainly concentrated at the negative moment zone of top surface and the positive moment zone of bottom surface.The tensile stress of galvanized steel deck and the reaction forces of griders and columns reflect the mechanism that the resistance is transferred from the failure area to the non-failure area.The compressive arch effect of G6 is greater than G1 and G2 at the early loading stage.However,the catenary effect can not be fully developed in G6 at the later loading stage due to the bad tension from the boundary conditions caused by the side-column removal scenario.At the initial loading stage,the main resistance is provided by the flexural mechanism of grider and slab mechanism.When the maximum vertical bearing capacity reaches,the resistance contributions of the flexural mechanism and catenary mechanism of grider and the slab mechanism account for 42.7%,23.8%and 33.5%,respectively.The contribution of steel bar truss slab to the progressive collapse resistance can not be negligible,accounting for approximately 30%.