非同时受压矩形钢管混凝土界面传力特性研究

受结构构造、施工方法及制作精度等影响，钢管混凝土桥梁节点区域传力较为复杂，压力荷载传递往往先由钢管或混凝土承担，经过一定长度后再由钢管和混凝土共同承担，钢管和混凝土非同时受压现象较为普遍。界面传力机理决定着非同时受压钢管混凝土构件、节点及界面抗剪连接件的工作特性。基于弹性连续介质层法，利用变形协调条件，建立了非同时受压矩形钢管混凝土界面传力理论分析模型，推导出剪力传递长度及界面纵向剪力的解析表达式。经有限元验证理论分析模型，进行了矩形钢管混凝土界面传力特性的敏感性参数分析，给出了矩形钢管混凝土剪力传递长度和界面纵向剪力的变化规律。结果表明：给出的界面相对滑移、界面纵向剪力、剪力传递长度等解析公式计算精度较高，可为钢管混凝土构件、节点及界面抗剪连接件的设计计算提供理论依据；剪力传递长度是反映钢管混凝土界面传力特征的关键指标，决定着钢管与混凝土协同作用范围及强弱；弹性工作阶段混凝土先受压和钢管先受压时界面剪力传递长度相等，与轴力无关，受界面剪切刚度影响规律相同；界面纵向剪力与轴力成正比；剪力传递长度随界面剪切刚度的增大而减小，与之呈负指数函数关系，随钢管、混凝土的轴压刚度增大而增大，与之呈...

Analysis on Interfacial Force Transfer Characteristics of Concrete-filled Rectangular Steel Tube Under Compression

By the structure, construction and manufacture, the force transmission in the joint area of the concrete-filled steel tube bridge is complicated. The load is often always by the steel tube or concrete at first, and is borne by the steel tube and concrete after a certain length, and the phenomenon of non simultaneous compression of the steel tube and concrete is more common. The mechanical properties of components, joints and shear connectors of concrete-filled rectangular steel tube are determined by the interfacial force transfer mechanism under non simultaneous compression. The theoretical model for the interfacial shear analysis of concrete-filled rectangular steel tube under non simultaneous compression was established based on the method of continuous elastic interlayer and deformation compatibility. The analytical expressions of shear transfer length and interfacial longitudinal shear were also proposed. The influence of the parameters on the interfacial force transfer characteristics of concrete-filled rectangular steel tube was analyzed based on the finite element analysis. The variation law of shear transfer length and interfacial longitudinal shear of concrete-filled rectangular steel tube was given. The results show that the analytical formulas of relative slip, interfacial longitudinal shear and shear transfer length presented in this paper are in high precision, it can provide a theoretical basis for the design and calculation of concrete-filled steel tubular members, joints and interface shear connectors; Shear transfer length is the key index to reflect the force transfer characteristics of the interface between steel tube and concrete, which determines the scope and strength of the synergistic action between steel tube and concrete. The shear transfer length is the same when only the concrete or the steel tube is compressed, which has nothing to do with the axial force and has the same rule under the influence of the interfacial shear stiffness. The interfacial longitudinal shear is proportional to the axial force; the shear transfer length decreases with the increase of the interfacial shear stiffness and shows a negative exponential relationship, the shear transfer length increases with the increase of axial stiffness of steel tube and concrete and the relationship is basically quadratic function.