【作者】 李威；

【导师】 韩林海；

【作者基本信息】 清华大学 ， 土木工程， 2011， 博士

【摘要】 钢管混凝土结构在建筑结构工程中正得到越来越广泛的应用。节点是结构受力的关键部位，深入研究钢管混凝土柱-梁连接节点的性能及其实用设计方法非常重要。本文对圆钢管混凝土柱-钢梁外环板式框架节点的抗震性能进行了研究，主要研究工作和取得的成果如下：1.进行了带楼板的圆钢管混凝土柱-钢梁外环板式框架节点在柱顶加恒定轴压力、梁端加往复荷载的试验研究。试验参数有：柱轴压比、梁柱抗弯承载力比和梁柱线刚度比。通过试验研究了上述参数对节点抗震性能的影响规律，分析了节点试件在往复荷载下的强度退化、刚度退化、延性和耗能能力等。试验结果表明，该类节点的荷载-变形关系曲线较饱满，节点刚度和强度退化稳定，抗震耗能能力良好。2.建立了圆钢管混凝土柱-钢梁外环板式框架节点在往复荷载作用下的精细有限元分析模型。该模型考虑了材料和几何的非线性、钢管和核心混凝土之间的相互作用、焊接残余应力和初始缺陷等因素的影响。给出了一种适用于混凝土塑性损伤模型的混凝土损伤指标取值方法，并应用到有限元模型中。通过与构件和节点试件在往复荷载下试验结果的对比分析，表明该有限元模型具有较好的精度和可靠性。3.基于试验结果和有限元模型，对圆钢管混凝土柱-钢梁外环板式框架节点的工作机理进行了细致分析。系统研究了该类节点的破坏形态和各设计参数下的极限状态，明晰了节点各部件在受力全过程中的内力、变形分布以及应力、损伤发展情况。系统分析了钢筋混凝土楼板、核心区轴压比、梁柱抗弯承载力比、梁柱线刚度比、环板和核心区性质等参数对节点抗震性能的影响规律。4.在参数分析结果的基础上，提出了一种圆钢管混凝土柱-钢梁外环板式框架节点的核心区剪力-剪切变形恢复力模型。建议并给出了一种适用于结构体系计算的节点单元模型，并将上述核心区恢复力模型应用其中。计算分析结果表明，上述恢复力模型和试验、数值计算结果均总体上吻合较好，提出的单元模型在结构体系计算方面具有较好的适用性。更多还原

【Abstract】 Concrete filled steel tubular (CFST) columns are being widely used in engineeringstructures in recent years. It is thus very important to thoroughly investigate theperformance of CFST column to beam joints, especially the joints with reinforcedconcrete (RC) slab. This paper evaluated the seismic performance of beam-columnjoints consisted of circular CFST column and steel beam with external diaphragm andRC slab through both experimental and numerical methods. The main research workand achievements are summarized as follows:1. Experiments are carried out on the composite joints with constant axial load onthe top of the column and reverse cyclic loading at the end of the beams. Theparameters include: the axial load ratio of CFST column; the beam to column strengthratio and the beam to column stiffness ratio. The influences of these parameters on thejoint cyclic behaviour as well as the failure modes were investigated. The resultsshowed that the load versus deflection curves were plump and stable strength andstiffness degradations were observed under cyclic loading. It is concluded that this kindof joints had a favorable hysteresis characteristic.2. Nonlinear finite element analysis (FEA) was conducted for the composite joints.The FEA model considered both geometrical and material nonlinearity, interaction andconnection between steel and concrete, residual stress and initial imperfection, etc.Damage indexes for both confined and common concrete under cyclic loading wereproposed based on the concept of “focal points method” from the stress-strainrelationship of confined and plain concrete. The accuracy of the FEA model wasverified by extensive experimental results, including results of structural member tests,joint tests from other researchers and joint test from the author.3. The failure modes, force transfer mechanism, force versus deformation relationsof the composite joints were analyzed by the FEA model. The failure modes of thejoints were categorised. The internal forces, stress and strain distribution at differentcharacteristic points on the force versus deformation relations were investigated. Acomprehensive parametric study was conducted. Influences of the parameters on thejoint behaviour were analyzed. The parameters included: the thickness and width of RCslab, the axial load ratio of panel zone, the beam to column strength and stiffness ratio, the properties of the external diaphragm and the panel zone, etc.4. A shear versus shear deformation hysteretic relation for the panel zone of thejoint was established based on the parametric analysis. A joint element model with thishysteretic relation implanted was proposed for joints in planar frame. It is concludedthat the proposed hysteretic relation and the joint element model had a favorableaccuracy when compared with the FEA and experimental results.更多还原