The Aseismatic Performance Research On Steel-beam-column Top-seat T-stub Connections

At present,in order to simplify the calculation in steel structure engineering design,it is usually calculated on the hypothesis that the connecting points of the beam-column joints of the steel frame are ideal hinged,which makes the design unsafe or too conservative.In fact,the beam-column joint of steel frame has enough non-linear deformation ability in actual working condition,which is between two hypotheses and is called semi-rigid connection.steel-beam-column top-seat T-stub connections is the most typical form of semi-rigid joint,the beam and column flange through the top and bottom T-beam with high-strength bolts together,many factors in the node assembly will affect the node's stress state.In this paper,we use ABAQUS finite element software,combined with the T-section steel joint test in literature,to do numerical simulation at first,compare the similarity and difference between the test and finite element analysis,so as to determine the rationality of finite element modeling.Using the idea of "strong joints and weak members",the structure of the joints is changed,including the addition of stiffener,the weakening of the flange of the beam,and the widening of the T-section steel with open holes in the web of the beam.The mechanical properties of different structural joints under monotone load and the seismic behavior under cyclic repeated load are analyzed.The following conclusions are obtained:1)Under the action of single-direction load,the additional stiffening rib can greatly improve the ultimate bearing capacity of the joints,but the ductility of the nodes is relatively low.It canincrease the ductility of the node while increasing the bearing capacity with T-stub widened.it ultimate bearing capacity of the node decreases less,but the ductility increases greatly with reduced beam sections.It ultimate bearing capacity of the node decreased,but the ductility increased the most with reduced web sections.2)Under cyclic load,the ultimate bearing capacity of stiffener joint is larger than that of T-stub widened,but the T-sub widened can better improve the energy dissipation capacity of the node.There is no obvious difference between the reduced-beam-section joint and the reduced-web-sections jonit in contrast of the ultimate bearing capacity of stiffener.but compared with the BASE,the energy dissipation capacity is significantly improved.3)The ultimate bearing capacity and deformation degree of the joint under cyclic loading are higher than the ultimate bearing capacity and deformation under single-direction load.4)The elastic region of beams,columns,T-stub and bolts in the joint area under cyclic load is obviously less than the single-direction load,and the area of each component area reaching the ultimate strength of the material increased,and the material strength can be fully exerted.