| T-shaped concrete-filled steel tubular composite structure not only has high strength, good ductility, excellent seismic behavior and a short construction period, etc., but also has the same limb thickness with the wall, to avoid the room appearing edges and corners which affect beauty. It also has the unique advantages on decorating space and improving the housing area. The prospect that is applied to actual engineering is well, so more and more domestic and overseas scholars have taken a watchful eye on it. But currently the research of the T-shaped concrete-filled steel tubular composite column is not much at home and abroad and there is nobody who engage in the theoretical and experimental study of the steel beam connection nodes. In this article, it shows experimental study on seismic performance and non-linear finite element analysis of the special-shaped concrete-filled steel tubular composite column and steel beam connection node, which give a great assistance to understand the seismic performance of the special-shaped concrete steel tubular composite column and steel beam connection node and promote the popularization and application. So this text has important theoretical significance and value in engineering. Meanwhile, the results will provide the reference for the establishment of "Technical Specification for Structures with Special-shaped Concrete-filled Steel Tubular Members ". Content and results of this study mainly include the following aspects:1. According to1:1.5proportion of scale,9T-shaped concrete steel tubular composite column and steel beam connection node specimens(3of extended end-plate connection node specimens,3of top and bottom angle steel connection node specimens,3of double web top and bottom angle steel connection node specimens) is designed and made for pseudo-static loading test. The article shows hysteretic performance, strength, degradation, stiffness degradation, ductility and energy dissipation of different kinds of high strength bolts or different thickness of top and steel plate node. According to the test phenomenon and results, we make a preliminary analysis on the failure characteristics and the failure mechanism of connection nodes.2. The low cycle reciprocating load experiment gives a good opportunity to study the seismic behavior of three kinds of T-shaped concrete steel tubular composite column and steel beam connected node. The test results show that:the hysteresis curves of all specimens are stable, and the curve shape of extended end-plate connection node is full and just like a spindle. All specimens consume less energy than most frame member and its energy dissipation coefficient is greater than2.01. The energy dissipation ability of the top and bottom angle connection node is not well and its energy dissipation coefficient is more than1.88. The curve shape of double web top and bottom angle steel connection node is not full, which has a better energy dissipation ability than the top and bottom angle connection node, and its energy dissipation coefficient is more than1.95. All the nodes have significant strength and stiffness degradation. The displacement ductility coefficient is equal to or even more than2. Equivalent viscous damping coefficient is greater than0.25.3. According to Rvafiq Hasan’s node classification method,9T-shape concrete-filled steel tubular composite column and steel beam connection nodes are analyzed. And the results of the study show that special-shaped concrete-filled steel tubular composite column and steel beam extended end-plate connection node and special-shaped concrete-filled steel tubular composite column and double webs top and bottom angle steel connection node is semi-rigid connection. And special-shaped concrete-filled steel tubular composite column and steel beam top and bottom angle steel connection node is semi-rigid connection in early loading stage, then belongs to hinged connection.4. On the basis of comparing ultimate bend and shear capacity, ductility and deformation ability of specimens, we analyse the main factors which have influence on the indexes and calculate the force of the specimens node domain and put forward some suggestions to improve node.5. According to the actual specimen size, we make non-linear finite element analysis on the seismic behaviour of special-shaped concrete-filled steel tubular composite column and steel beam extended end-plate connection node, and double webs top and bottom angle steel connection node by using the finite element analysis software ANSYS10.0. On the basis of the results of analysis, the situation of the stress distribution of specimen node domain and the hysteretic performance of those nodes are examined and compared with the experimental results. Then some parameters which have influence on the seismic performance have been analysed according to the verified finite element model, including strength of the filled concrete, compressive ratio, thickness of steel tube. The analysis results show that:the finite element calculation results coincide with experimental results. It shows that the calculation of steel and concrete constitutive model, the finite element model, the solving method is reasonable and reliable. The calculation model can be used to provide reference for the subsequent analysis of many parameters. The axial compression ratio (0.2-0.5) has little effect on node capacity but a greater impact on the aseismic performance of the joints; the strength of the filled concrete on load-carrying capacity of small effect, and have a certain influence on the aseismic performance of the joints; the thickness of steel pipe have a great influence on bearing capacity, but less influence on the aseismic performance of the joints; the steel yield strength have large influence on ultimate bearing capacity, and the more obvious effects on the aseismic performance of the joints.On the basis of summing up the work, the research prospect is put forward. |
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