Research On Hysteretic Behavior Of Multi Branch T-type RHS Joints

Hollow Section Structures (HSS) are applied in almost all the fields of civilengineering for their advantages such as clean and graceful architectural modeling,excellent structural property and extensive applicability. At present, static designmethod which bases on the static properties of tubular joints has tended to perfection,but seismic design method has not been quantified because only a few of investigationshave been done about the seismic behavior of tubular joints. In this case, there arehidden troubles behind the HSS been widely used. It is necessary to carry out a largeamout of research work on the seismic behavior in order to change this situation. In thisthesis, hysteretic behavior of multi branch T-type rectangular hollow section (RHS)joints were analyzed by experimental and finite element (FE) methods. The details arepresented as follows:Experimental tests are carried out on multi branch T-type RHS joints subjected toquasi-static cyclic loads. It can be observed from the test that failure frequently occuredat the weld toe which located along the chord surface, then the penetrating cracksformed which caused by rapid crack propagation due to cyclic loading. The hystereticcurves of tested joints are plump. The influence of annealing treatment and geometricalparameters on the tested joints’ hysteretic behavior were analyzed. The results indicatethat annealing treatment significantly increases the ductility ratio, the energy dissipationvalue and energy dissipation factor of the joint. With increasing width ratio of thebranch-to-chord and decreasing width-to-thickness of the chord, the ductility ratio, theenergy dissipation value and energy dissipation coefficient increases obviously for joint.ANSYS is used for numerical analysis in this dissertation. In the FE model,SOLID95elements and the bilinear stress-strain relationship are adopted. Results ofsimulating indicate that the FE model can be used to estimate the hysteretic propertiesof multi branch T-type RHS joints before the cracks form. Parameter analysis of themulti branch T-type RHS joints’ hysteretic behavior was also developed by means of FEmethod.