Experimental Research On Static Behavior Of T-type And Y-type RHS Joints With Chord Plate Reinforcement

In recent years,more and more structures use Hollow Section Structures(HSS),and the load-bearing capacity of the structural engineering requirements are also increasing.HSS are widely used in many areas,but it can not be used in some structures for the load-bearing capacity of individual joints can’t satisfy design demands.So experts and scholars began to study reinforced joints.The method of RHS joints reinforced with plate on the flange of chord is accepted by many experts,because it is convenient and easy to implement.At present, the domestic and foreign researches on reinforced joints are still imperfect,and there are no definite design formulas for reinforced RHS joints in design code of steel structures in our country.Based on the research results of reinforced joints obtained in our country and other countries in recent years,this paper studied the ultimate strength and related failure mode of T-type RHS joints reinforced with plate on the flange of chord by experimental tests and numerical analysis.In addition,this paper also studied the ultimate strength and related failure mode of Y-type RHS joints reinforced with plate on the flange of chord by numerical analysis,which would be meaningful for the revision of our country code and the engineering application of this joints.Specific contents are as follows:(1) In this paper,static tests were carried out on thirteen T-type RHS joints(including twelve joints reinforced with plate on the flange of chord and one unreinforced joint),and also a detail analysis and comparison of the ultimate strength and failure modes of different stiffening joints are made.(2) Using ANSYS finite element software simulate test joints.The factors of boundary conditions,1/4 model, weld size and nonlinear material were considered when building the FE model.By comparing the test results to the FE results,it fully verified the accurancy and validity of the ANSYS finite element model.(3) The geometry and material properties of test joints were substituted into the related formulas which are derived from existing literature.By comparing the calculation formular results with the experimental results and the ANSYS results,it aims to verify the accurancy of the formulas and discuss the application range of the formula.(4) Parameter analysis of Y-type joints reinforced with plate on the flange of chord is mainly aimed to investigate the influence of these geometrical parameters on its ultimate strength and failure mode.These geometrical parameters are the angle of the brace to chord θ,brace to chord width β,ratio of half brace width to brace thickness γ,the length of stiffening plate lc, the width of stiffening plate bc and the thickness of stiffening plate tc.According to the results of parameter analysis, a summary is made about the failure mode and the change rules of ultimate strength.In addition, the proper stifferning plate dimensions are discussed,which can ensure the efficiency of joints greater than 100% under certain conditions.