Study On The Mechanical Behavior Of The Joint Transferred From Two Inclined CFT Columns To A Supporting CFT Column Under Cyclic Load With Different Axial Compression Ratio

The development of function and structure form for tall or supper tall building has a tendency of diversification, which results in the wide application of transfer story in practical engineering. With the advantages of transmitting force directly, higher bearing capacity, smaller section, better service space, and significant economy benefit and so on, the inclined column-shaped transfer structures with concrete-filled steel tubular(CFST) members have a wide application prospect. Based on the research of predecessor, three joints were designed and experimented under cyclic load on steel beams. With the help of ABAQUS, simulations of these joints have been performed to study the Joints’ mechanical behavior. The results of this study can provide significant academic value for perfecting the theoretical research system about the mechanical behavior of the joint of CFST structure under complex load conditions. Meanwhile, it can also provide theoretical basis and design reference for engineering.The main jobs finished in this study are as the following aspects:(1) Three specimens under different axial compression ratio were designed and conducted to cyclic load experiments. Experiment results indicate that the core center of the joint has high stiffness that few displacements could be detected. The intersectional area of two inclined CFT is still weak spot that need to be concerned. As axial ratio goes higher, the more likely intersectional area could collapse.(2) Finite element model(FEM) was established in FEA software ABAQUS to simulate experiment condition. By comparing the analysis results with experiment results, the FEA simulation was verified to be feasible and reasonable. FEM results also show that as long as the vertical bearing capacity is the control factor of inclined CFT parts, the joint could function normally under complex stress condition.(3) Based on the experiment results, FEA results, and currently national specifications, several reasonable suggestions and a possible design method are proposed.