Study On Load-Carrying Capacity Of New Concrete-Filled Square Tubular Column To Steel Beam Connections With Anchorages

Concrete-filled steel tube has been researched and applied in civil engineering increasingly in resent years. The traditional connections types of concrete-filled square tubular column to steel beam mainly include external diaphragms and internal diaphragms in steel tube column, joint patterns are singleness. The internal diaphragms can only be welded on three edges, but not be welded easily on the forth edge for middle or small dimensions tube column. Referencing some joint forms of beam-to-circular steel tube confined concrete, T-shaped steel anchorages connection for middle or small dimensions square tubular column was put forward in this paper. They consist of the web of T shaped anchorage being set vertical called I type and horizontal called II type.Anchorages transfer the end bending moment of beam to frame joint. The non-linear FEM model involving geometric large deformation and materials non-linear presented FEM software(ANSYS) was used to analyse anchorage pulled out from the column. Which simulate analysed the force transferring mechanism of joint, and get the failure mode of joint. Finally the design formulas of the resistance pulling out capacity and proposes of construction were suggested.The model between bending moments reverse points which bend stiffness ratio of the column and beam are close were choose from frame structure under horizontal seismic action, and analysed the capacity behavior of connections under the monotonic loading. The results of non-linear FEM analyses show the stresses distribution of the joints better, and can be observed in the details. Then the influences of various factors on joints capacity behavior were analysed such as axial compression force ratio and strength classes of concrete.Based on the achievements in theoretical research in this paper, the design provisions on concrete-filled square tubular column to steel beam connections with anchorages were discussed, and detailing requirements and load-carrying capacity formulas according to general design requirement were recommended. They can provide the reference to the engineering design.