Numerical Analysis Of The Mechanics Performance On CFST Column-steel Beamjoint With Outer Stiffened Ring

Concrete filled steel tubular structure is a type of new structure that can use theadvantage of steel and concrete. Owing to its good behavior, the new structure is usedmore and more widely. Along with widely spread use of CFST（concrete-filled steel tube）structure, people have paid more attention to the design of CFST joint. The designs of thejoints have a great impact on the strength, rigidity and stability of steel structures. With thestructural manifold forms the joint types of beam and column are varied. The strengthenring joint is a joint type recommended by the procedures， which is apply to the connect ofsteel beam or precast concrete beam and column， but the specific design method ofstrengthening ring node is not given in procedures， and the calculation methods of thejoint bearing capacity and the Rigidity are to be perfect. To determine a theoretical modelwhich is reasonably reflected the stress mechanism of the joint core area， and to analysisthe node system parameter， is the key to improve calculation method of node bendingstrength. Therefore， it is necessary to analysis the mechanical properties of strengthenring node on the overall system.Base on the researches of the CFST frame node at home and abroad， and accordingto the previous existing experimental and theoretical research results， some works of thisarticle were in the following:On the base of reading literature in quantity， according to the general principles ofthe node design from the norms， the finite element model of concrete-filled steel tubecolumn-steel girder node is established， through a large number example analysis oftypical nodes， the rationality of the model is validated in this paper.This paper adopts ABAQUS finite element analysis software to study the mechanicalproperties of the joints with outer ring stiffeners under monotonic load. Some geometricparameters are used in the paper, such as the flange width and thickness of beams, the webheight and web thickness of beams, the wall thickness of columns, the height of outer ring. Theinfluence curve of the connection’s bearing capacity and rigidity can be drawn from the variation of impact parameters which have an impact on the ductility, bearing capacity andrigidity of the connections. The deformations of the connection with outer ring stiffeners whichformed by monotonic load include the distortion of columns, the distortions of columns and theshear deformation of node domain. The impact of joints with outer ring stiffeners due to theshearing deformation of node domain with thechanges ofsingle parameter is analyzed.From the research results, the flange width and thickness of beam, the wed thickness ofbeam and the height of outer ring all have an impact on the capacity, rigidity, ductility, stresscloud and the shearing deformation of node domain. The wed thickness is not the mainparameter which influences the mechanical property of connections. The computing formulasof bearing capacity and rigidity are raised and the confidence coefficients of the formulas areanalyzed.