Nonlinear Finite Element Analysis Of CFSST Columns And H Shape Steel Beams Semi-rigid Connections

The concrete filled square steel tube (CFSST) column steel frame structures are more and more widely used for the advantages such as more economical, higher strength, better rigidity and seismic performance, short construction period and so on. But there are little theory and test research of the connections between the concrete filled square steel tube columns and H shape steel beams in our county,so it has important theory and application value to research the connections between the CFSST columns and H shape steel beams for the development and application of the CFSST column frames .All over the world,the experirnental study on seismic performance of CFSST columns and H shape steel beams connections, especially semi-rgid connections,is elementary for their different forms and complicated seismic performance.To research The Capacity behavior of CFSST columns and H shape steel beams connections,four different Specimens are designed and tested under the low cycle reverse loads. The 3D solid finite element models are built by the dimension of the CFSST specimens, and the nonlinear finite element analysis is done using software ANSYS. The results of finite element analysis coincide to the results of the experiments. According to the character of CFSST ioints,spread-finite element model is adopted.Different element types are used in the models and bond-slip behavior is taken into account between the steel bolt and steel.all components on the core of CFST ioint.We assumed that Concrete and steel tube are fully bonded. A good correlation between the finite element models and the experimental results is obtained.An analysis is developed for influence factors that have some influence on the CFSST ioints'behavior.The results show that the thickness of steel tube, the height of beam , the thickness of flange ,the thickness of web , the thickness of angle have a good andvisible effect on the capacity of joints;the height of beam has large influence , the thickness of steel tube has little influence.At last, several problems which are arising while the paper is writing have been summarized. And the author put forward some problems of the study on the cooperation status in-between steel tube and in-core concrete in CFSST structures to be researched more deeply and makes an expectation of the wider applied foreground of CFSST structures.