Hysteretic Behavior Of Steel Tube-reinforced Concrete Column And Steel Beam Joint

With the increasing use of steel tube-reinforced concrete (STRC) column in building structures, it would be particularly important to study the fundamental mechanics properties of STRC columns. Joints are the key part of the structure. Thus, it has a high research value and practical meaning to study the performance of STRC column and steel beam joints. In the context of STRC column and steel beam joints of a real project, this paper studied the hysteretic behaviour of this kind of connection. The main research work and achievements are summarized as follows,(1) The hysteretic tests of four connections between STRC columns and steel beams were carried out with the main parameters of the axial compression ratio and whether to supply the RC slab. The load was applied on the end of the beam. Meanwhile, the constant axial load applied on the top of the column. The results showed that the hysteretic curves were plump and stable. Strength and stiffness degradations were observed under cyclic loading. It means that this kind of joint has a good seismic performance.(2) Finite element analysis (FEA) software ABAQUS was conducted numerical modeling. The geometrical nonlinearity, material nonlinearity, the contact between the steel surface and the concrete surface, interaction between steel bars and concrete and initial imperfection were considered in this FEA model. The existing test data were used to verify the accuracy and reliability of this FEA model.(3) Based on this FEA model, this paper conduct a whole-process analysis of this kind of joint. The failure mode, the development law of stress and strain of this kind of joint was clearly understood as well. At the same time, a large number of parameters analyses were carried out. The parameters included the axial load ratio of column, the ratio between the bending capacities of the beam and column, the beam to column stiffness ratio and the steel ratio of columns, the ratio of inside concrete strength to outer concrete strength and whether to supply the RC slab. The influence of the parameters on the hysteretic behaviour of this kind of connection was studied. The bearing capacity is affected by the axial load ratio of column, the ratio between the bending capacities of the beam and column and whether to supply the RC slab obviously. The beam to column stiffness ratio, the steel ratio of columns and the ratio of inside concrete strength to outer concrete strength influence the bearing capacity not obviously. All of the parameters affected the rotational stiffness no significant effect.