Finite Element Research On Behavior Of New Type Joint Of Concrete-filled Steel Tubular Column With Reinforced Concrete Beam

With the development of high-rise building, the application of concrete-filled steel tubular(CFST) becomes more and more popular. It has many merits as high strength,good plastic and tenacity,the convenience of construction,high fire-resistant,cheap cost, etc and it is a composite construction which has roominess foreground. The design of joints is the key that CFST is applied in high-risebuilding. For the time being the research on concrete-filled steel tubular joints is preliminary. Additionally current joints applied in engineering practice have the disadvantages of structure complicacy,the complicacy of construction and undefined force transfer. A new type of connection between concrete-filled steel bar and concrete frame beam with steel bar run-through was put forward in the reference literature . It not only makes steel bar of the beam run-through at core area of the joint but also makes the concrete connect both inside and outside of the steel tube. It improves the rigidity and entirety of the connection. In order to be discussed emphatically, the joint with small holes and a transient joint were also introduced in the the reference literature. The joint with small holes was already applied in the engineering. The transient joint is a joint which characterized with big holes and strengthening ring and stiffing ribs at core area of the joint. The mechanical performance of three joints was studied in the reference literature by comprehensive contrast and analysis of the three joints under the cyclic load in experiment and FEM. But there are some problems in the above-mentioned study. For example,the model of concrete was not correct and Bond—slip was not taken into account in the study, etc.The main work of this thesis is to use finite element method to study the behaviour of these three joints under unilateral loading and reversed loading by choosing models,setting relevant parameters reasonably and using nonlinear spring element in ANSYS which is used to simulate bond-slip seismic behavior in the working of joints. The results are then compared with testing results. The mechanical performance of force transfer and seismic performance are investigated in order to provide instructions for the engineering application.