方钢管混凝土结构作为一种新型组合结构，具有承载力高、耗能能力强、延性好等特点，且外形规则便于梁柱连接，防火措施简单，施工周期短，因此，在中高层住宅建筑中有较广泛的应用前景。然而，目前制约方钢管混凝土结构推广应用的主要问题在于节点处构造复杂，没有简明实用的受力计算公式。因此开展对方钢管混土柱框架节点域的受力性能及节点域的承载力的研究，具有十分重要的理论意义和应用价值。 在总结前人研究的基础上，应用虚功原理对现有的节点承载力计算公式提出了改进，提出了简明实用的节点抗剪、抗弯承载力计算公式。应用本文公式和规程中推荐公式对三组试件进行计算, 相比之下,本文公式考虑了轴压比的不利影响,结果较《规程》公式小10%左右,与工程实际更为相符。 建立了同时考虑大变形的几何非线性、各种材料非线性等非线性因素的有限元理论分析模型，利用大型非线性有限元软件ANSYS8.0，对钢材采用Von.Mises屈服准则和运动强化本构关系，对混凝土采用William-Warnke五参数破坏准则和弹塑性本构关系，采用三维实体单元对“带内隔板方钢管混凝土柱－钢梁节点”进行了三维建模，并模拟分析了单调加载下节点的受力性能、节点区应力分布，以弥补试验中无法直观地了解各细部受力情况和改变各种参数进行对比的缺陷，得出了柱壁厚度、混凝土强度、内隔板厚度、梁截面尺寸等对节点性能的影响规律，得出节点处荷载－位移曲线图，对钢管混凝土节点的构造提出几点设计建议。 ANSYS计算结果与公式计算结果进行对比，两种结果符合良好。

As one of new composite structures in the field of Civil Engineering,concrete-filled rectangular steel tubular (CFRT) structure has high capacity, large energy absorption capacity, and high ductility, also it has regular shape which is easy to connect between columns and beams,convenient fire-control measure and short construction time.Therefore CFRT structure will become popular in medium-high rise residential construction.At present time, however, critical factors for which extensive applications of CFRT structure will be influenced is joint detail scheme.And there is no simple mathematical formulas for Load-carrying capacity of joint region.Thus investigation on joints between CFRT columns and steel beams in medium-high rise residential construction has significant theoretical and applied value. Based on the theoretical analysis, the mathematical formulas for determining joint shearing capacity and bending capacity were developed by using the principle of virtual work in this paper. Nonlinear FEM model involving geometric large deformation and materials nonlinear is presented.The Von.Mises failure criterion and multiplier kinematical hardening stress-strain relationships have been used for steel and the William-Warnke failure criterion and elastic plastic stress-strain relationships used for concrete.The 3D models of beam-to-column connections with internal diaphragms by 3D solid elements are founded.And the capacity behavior of connections under the monotonic loading are analyzed. The results of nonlinear FEM analyses can show the stresses distribution in the joints better, so that it provides the possibility to patch up the defects that couldn't observe in experiments in the details.And then,various factors of the influences of joints capacity behavior can be analyzed such as changing thickness of steel columns and internal diaphragms ,concrete strength,and sectional dimension of beam etc.Finally some suggestions for improving joint design are presented according to comparison of theoretic analyses. Comparison between calculation results of ANSYS and theoretical results shows that the two agree better.