【作者】 张冬芳；

【导师】 赵均海；

【作者基本信息】 长安大学 ， 结构工程， 2013， 博士

【摘要】 复式钢管混凝土柱具有较高抗压承载力，在强地震作用下能体现出很好防倒塌能力，可将其用于大跨度桥梁或超高层房屋建筑中。内圆外方的复式钢管混凝土柱同时兼有整洁美观及节点构造简便等特点，故在工程中日益受到重视。然而，目前国内外对复式钢管混凝土柱-钢梁连接节点的研究较少，阻碍了复式钢管混凝土柱结构的发展应用，所以有必要研究新型复式钢管混凝土柱-钢梁节点的设计方法及抗震性能。综合我国现状及目前钢管混凝土柱节点的研究成果，本文设计了一种新型复式钢管混凝土柱与钢梁的连接节点形式，对其进行了低周往复荷载试验，同时采用数值模拟及理论分析相结合的方法对此类新型节点进行深入研究，主要研究内容和取得的成果如下：本文对6个新型复式钢管混凝土柱-钢梁节点试件和1个单钢管混凝土柱-钢梁节点试件进行了低周往复荷载作用下的试验研究，此类新型节点的传力构件包括锚固腹板、水平端板、连接板及竖向肋板。结果表明：竖向肋板外伸长度可有效调节节点破坏时塑性铰位置，锚固腹板加肋可有效提高节点承载力；此类新型复式钢管混凝土柱-钢梁节点的破坏模态基本为水平端板与钢梁翼缘连接处出现塑性铰破坏；复式钢管混凝土柱节点与方钢管混凝土柱节点相比，承载力较高、耗能能力强、刚性和延性均较好，适用于抗震设防区的钢管混凝土结构中。采用有限元分析软件ABAQUS对新型复式钢管混凝土柱-钢梁节点模型进行非线性有限元分析。数值分析得到的滞回曲线、骨架曲线及节点破坏模态与试验结果吻合良好，证明了有限元模型在选取单元类型、材料本构及破坏准则方面的合理性。在此基础上，对复式钢管混凝土柱-钢梁节点进行了应力分析，此类新型节点传力路径明确，在高轴压比作用下具有良好的工作性能，锚固腹板加肋传递节点应力的能力更好。在数值模型的基础上，对典型节点试件SBJ2-2进行系统参数分析。对比了梁端加载方式与柱端加载方式对节点破坏模态的影响；确定出竖向肋板与锚固腹板的合理高度；得出了各组参数下节点的弯矩-转角曲线及对应的节点初始刚度曲线；采用三参数幂模型建立了此新型节点的弯矩-转角实用计算式，拟合出节点的初始刚度计算式；根据节点弯矩-转角计算式所得结果与试验、数值模拟结果进行对比，吻合良好。本文建立的节点弯矩-转角全过程计算式可评价各个设计参数对节点受力的影响程度，为此类新型节点的工程设计奠定理论基础。研究此类新型复式钢管混凝土柱-钢梁节点的抗剪受力性能。考虑节点在竖向轴力和梁端往复荷载作用下，钢管柱壁的环向拉应力对抗剪承载力的削弱作用；节点域的钢材采用抗剪三折线模型，内外层混凝土采用上升段和水平段抗剪模型，将各部分叠加建立了此类新型节点的抗剪承载力计算式；其中外方钢管腹板与竖向肋板对节点抗剪承载力的贡献值较大；将抗剪承载力计算结果与试验结果进行对比，两者吻合良好，从而验证了此类新型节点抗剪承载力计算方法的正确性。更多还原

【Abstract】 Concrete-filled twin steel tubes (CFTSTs) column, which has been widely used in thelarge-span bridges and high-rise buildings nowadays, is characterized by its high-strength, andespecially good resistance against the strong earthquake loading. CFTSTs column, composingof an outer square steel tube and an inner circular steel tube, has the advantages of not onlygood mechanical performance but also the convenient connection. Therefore, the CFTSTscolumn has attracted increasing attention in the engineering world.Up to now, there is very limited available literature in regards to the connection betweenthe CFTSTs column and the steel beams. Thus, it is necessary to develop new types ofconnection of CFTSTs column to steel beams, investigating their behaviors under seismicload and establish the design methods accordingly. In this dissertation, six connections ofCFTSTs column to steel beams and one Concrete-filled steel tube (CFST) column to steelbeams were designed. Also, the seismic behavior of different types of connections wasanalyzed in details by means of experimental tests, numerical simulation and theoreticalanalysis.Firstly, six new connections of CFTSTs column to steel beams and one connection ofCFST column to steel beams were designed and tested under the lateral cyclic loads. The testresults showed the overhang length of vertical rib plates can adjust the position of the plastichinge for the connections. The bearing capacity for the connections of anchorage webs withribs was also shown to be better than the anchorage webs without ribs. The new typeconnection of CFTSTs column to steel beams has high bearing capacity, good energydissipation, stiffness and ductility.The seismic behavior of the suggested connections was developed and analyzed by aNon-linear finite element software ABAQUS. Comparison of results between the simulationand the test has shown good agreement. Moreover, discussion on the stress distributions of theconnections has shown good performance under high axial ratio. And the connections ofanchorage webs with ribs can transfer stress well. A series of parametric analysis have been carried out for the specimen SBJ2-2based onthe verified finite element model. Different failure modes were found when the loads wereadding at different positions i.e., the end of beam segments and the top of column. The properheight of the vertical rib plates was determined according to the results of simulation. Thecurves of moment-rotation and initial stiffness for the connection were obtained by theparameters analysis. The practical formula of this new type connection was derived accordingto the three-parameter power models, and the fitting formula of initial stiffness for theconnection was retained according to the parameters analysis. Comparison of results amongthe theoretical calculation, the simulation and the test has shown good agreement.The shear capacity of the new type connections of CFTSTs column and steel beams wereproposed, taking into the effect of the axial load and the low cyclic load at beams ends. In thetheoretical derivation, the simplified tri-linear model was used for steel, whereas the ascentstage and horizontal segment model was used for the inner and outer concrete. Additionally,the formulae of the shear capacity and the corresponding shearing deformation of theconnections were derived. Comparison of the calculated shear capacity with the experimentalresults has shown well agreement. Therefore, the proposed method could be used to derive theshear capacity of the new type of connections.更多还原