【作者】 高山；

【导师】 张素梅； 郭兰慧；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2014， 博士

【摘要】 建筑结构一旦发生连续性倒塌，必将造成严重的人员伤亡和巨大的经济损失。因此，结构的抗连续倒塌性能已引起学者和工程界的广泛重视。当结构中的竖向承重构件发生破坏，结构将通过由节点和梁组成的“悬索作用”来承担竖向荷载。在抗倒塌设计中采用承载力高、变形能力好的节点连接，可以充分的发挥悬索作用，保证结构将上部荷载充分并平稳的传递给周边构件。在正常使用荷载作用下，节点承受负弯矩的作用，而当柱失效后，“悬索作用”将在梁中产生拉结力，失效柱上方节点将承受正弯矩和拉力的共同作用，而相邻节点将承受负弯矩与拉力的共同作用。因此，结构体系中的节点性能的研究和设计将是结构抗连续倒塌设计中的关键指标之一。现有结构体系的连续倒塌性能研究多侧重于钢框架和钢筋混凝土框架，对组合梁钢框架的研究则较少。而对于抗连续倒塌体系中节点性能研究则通常采用简化的边界条件，针对组合节点在弯矩和拉力共同作用下的性能也关注较少。为此，本文对组合梁平面钢框架的连续倒塌性能和组合节点的受力性能进行了较为系统的试验研究和理论分析，具体包括以下四部分内容：(1)完成了2榀四跨单层组合梁平面钢框架的抗连续倒塌性能试验研究，考察了焊接刚性组合节点和平齐式端板连接半刚性组合节点对结构体系抗连续倒塌性能的影响。实测了失效柱柱顶荷载、位移以及框架水平位移，获得了框架梁梁端和跨中应变的分布与发展规律，得到了受荷过程中梁中拉力和弯矩的传递过程和规律，比较了梁柱连接方式对组合梁平面钢框架抗连续倒塌性能的影响。(2)完成了12个钢-混凝土组合节点的试验，考虑了刚性组合节点和平齐式端板半刚性组合节点在纯弯、拉弯和受拉三种工况下的受力机理。实测了组合节点的弯矩-拉力曲线、弯矩-转角曲线和拉力-位移曲线，获得了受荷全过程中梁端的应变分布、发展以及试件的变形特征。基于试验结果和已有的理论分析，提出了组合节点拉弯受力状态的承载力设计方法，并分析了组合节点在抗倒塌过程中不同受力阶段的工作机理。(3)采用ABAQUS建立了刚性连接和半刚性连接的组合梁平面钢框架有限元分析模型，在半刚性连接框架中采用混合单元建模，考虑螺栓断裂后能更精确模拟平齐式端板连接半刚性组合节点在结构体系中的受力性能。探讨了钢梁截面高度、混凝土板厚度、配筋率、节点连接刚度等参数对关键柱破坏后框架抗连续倒塌性能的影响。基于理论分析和试验研究，提出了组合梁平面钢框架简化分析模型及压拱效应模型，并推导了竖向荷载-位移计算方法。(4)建立了三层和九层组合梁平面钢框架有限元模型，对其进行了动力拆柱分析，研究不同层高、不同位置的关键柱破坏后相应节点和结构体系的动力响应和受力机理，确定影响范围及连接性能对结构抗连续倒塌性能的影响规律。通过分析最终提出可用于多层框架结构抗连续倒塌性能分析的简化模型。更多还原

【Abstract】 The progressive collapse of buildings would result in significant casualties and property loss. Hence the study on the progressive collapse resistance of structures has drawn more attentions among researchers and engineers. Once the vertical load-resisting component in structure is damaged, the beams and joints above the damaged component would carry the vertical loads through “catenary action”. The joints with high moment-resistance and good ductility play an important role in the formation of catenary action and redistribution of internal load. Normally, the joints under service loads sustain hogging moment. Tensile loads would appear in the beams due to catenary action under column loss. Hence the joint would sustain bending moments combined with tension. The behavior of the joints under the combination of moment and tension is a key factor in the design of preventing progressive collapse.Previous studies were mainly focused on steel structures or reinforced concrete structures. Fewer attentions were paid to steel-concrete composite structures. Although some studies were conducted recently to investigate the performance of the connection under the scenario of column loss, only the beam-to-column connections were tested within a simplified boundary condition. Specially, the combination of bending moment and tension is rarely considered in the study of composite joint. In this paper, the experimental study and theoretical analysis have been carried on the progressive collapse behavior of planar steel frame with composite beam and the moment-tension performance of composite joint. The main research is listed as followed:(1) Two1-storey4-bay planar steel frame with composite beam were tested under the loss of middle column. The influence of fully welded rigid connection and flush endplate semi-rigid connection on the progressive collapse resistance of structures was considered in the test. The measurement included the vertical load and displacement of the loss column head, the horizontal displacement of frame column and the strains at the beam ends and the mid-span. The transfer mechanism of tension and moment in the loading process was achieved. The influence of beam-to-column connection configuration on the behavior of composite frame under column loss was also analyzed.(2) Ten tests of composite joints were conducted. Two joint types of rigid connection and semi-rigid connection and three load conditions of pure bending, bending combined with tension and pure tension were employed. The moment- rotation relationship curves, moment-tension relationship curves and tension-displacement relationship curves were drawn in the test. The strain distribution and development at the beam ends and the deformation of joints in loading process were also captured. Based on the test results, a moment-tension relationship formula for composite joints was proposed and the mechanism of composite joints in the collapse process was studied.(3) Finite element models for planar steel frame with composite beam were developed by using the software ABAQUS. For semi-rigid composite frame, the mixed-element method was considered and the material fracture was also considered. The influence of height of steel beam, depth of concrete slab, rebar ratio and connection rigidity on the performance of composite frame under column loss was studied by using the FE models. A mechanical model for planar steel frame with composite beam under column loss and an arch action model were proposed. The load-deformation formulae corresponding to the mechanical model and arch action model were also derived.(4) Finite element models for3-storey and9-storey planar steel frame with composite beam were developed. Based on the models, the dynamic column removal analysis was conducted. The dynamic response of the structure under different column losses was studied. The affected area under column loss and the influence of connection behavior were certified. A simplified model for analyzing progressive resistance of multi-storey was suggested.更多还原