Study On Behavior Of Enforced Loop Joint Of CFST

At present,the concrete filled steel-tubular structure has been used in many hight - building ,but the CFST column connected beam have a lot of questions,need to study deeply. Using Ansys software,carry finint element analysis on enforced loop joint of CFST.Compared with result of experimentation, finint elemnt model can simulate real structure effectively.Through ten F.E. models, study on enforced loop plane from five aspects:(1) width of enforced loop plane;(2) thickenss of enforced loop plane;(3) thickenss of steel tubular;(4) axial load,(5) model of load.The analytical result is : With width and thickenss of enforced loop plane increased,the bearing capacity of joint has been improved obviously.So width and thickenss of enforced loop plane is important factors that affect bearing capacity of joint.As thickenss of steel tubular increased, loading capacity has been improved ,so thickenss of steel tubular is not important factor. When put axial load on column, stress of enforced loop plane has been improved.Stress maximum that value has been increased,the maximum is less than stress on final load,axial load contribute to loop stress value relatively lightly,thus needn't consider affecting on joints.As putting singal load, fivty precent of maximal stress and strain of enforced loop plane focus on area that is less than 45owith axis of beam.It is to say that load affection is limited,focusing on 45orange.As putting two load, different direction stress of enforced loop plane superimposed in 45o range. Yield area of enforced loop plane is range that is less than 45o with axis of beam,so 45osection of enforced loop plane is unsubstantial part.Distributing of stress and strain on 45o section is declining line,high stress and strain focus on inside of enforced loop plane.So suppose distributing of stress and strain on 45o section is straight,it adapt to real structure and suit to safe design.Accdording to analysis on theory,put forward the design method.The design method is simple and suit to different type. It is valuable method for design of CFST structure.