考虑楼板作用的RC框架压膜机制抗倒塌承载力分析

黄远 洪露露 易伟建

摘   要：为研究考虑楼板作用后钢筋混凝土框架结构的压膜机制抗连续倒塌性能，利用SAP2000建立了框架梁板子结构连续倒塌有限元分析模型，通过已有的12个抗连续倒塌试验验证了分析模型的准确性和合理性. 在此基础上，通过定义考虑楼板作用后压膜机制抗连续倒塌承载力提高系数，研究了混凝土强度、楼板厚度及配筋率等参数对承载力提高系数的影响规律. 结果表明：考虑楼板作用后，结构的抗倒塌承载力将显著提高，增大靠近边柱梁端的压拱效应，减小承载力再次上升时的位移. 承载力提高系数随着混凝土强度等级、板的长宽比、梁底配筋率、梁高的增大而显著增加;承载力提高系数随着楼板厚度、板顶配筋率、板底配筋率、梁顶配筋率的增加而减小.

关键词：楼板;连续倒塌;混凝土框架;承载力;数值分析

中图分类号：TU375.4                             文献标志码：A

Abstract：To study the progressive collapse resistance of reinforced concrete frame structures considering floor slab action， a finite element model for progressive collapse analysis of beam-slab structures was established using SAP2000. The accuracy and rationality of the analysis model were verified by 12 specimens from the existing progressive collapse tests. Then， we defined an increasing factor for assessing the compressive membrane mechanism based progressive collapse bearing capacity considering the action of the floor slab. The influence of parameters，such as concrete strength， slab thickness， and reinforcement ratio，on the increasing factor was studied. The results show that，after considering the action of the slab， the collapse resistance of the structure increases significantly，the compression arch effect of the beam near the side column beam also increases， and the displacement reduces when the bearing capacity rises again. The increasing factor of bearing capacity increases significantly with the increase of the concrete strength grade， the aspect ratio of the slab， the reinforcement ratio at the bottom of the beam， and the beam height. However， the increase factor of the bearing capacity decreases with the increase of the thickness of the slab， the reinforcement ratio at the top and bottom of the slab， and the reinforcement ratio at the top of the beam.

Key words：slab;progressive collapse;concrete frame;bearing capacity;numerical analysis

自英國的Ronan Point公寓倒塌事件以来，建筑结构的抗连续倒塌性能引起了广泛关注. 国内外学者对纯框架结构抗连续倒塌中的受力机制[1-2]、性能评估[3-4]、动态效应影响[5-6]等进行了深入研究. 在实际工程中，楼板作为框架结构的水平构件，对结构的抗倒塌承载力的贡献不可忽视. 初明近等[7]进行了单向梁板子结构中柱移除的试验，研究梁板相互作用与荷载传力机制，表明楼板能够提高结构抗倒塌承载力. Pham等采用12点加载方式开展了一系列梁板子结构在均布荷载下的倒塌试验，研究了……