Research On Seismic Performance Of Slit T Connection Steel Frame

The beam and column connection is one of the most important parts of the steel frame structure.The traditional rigid connection of the steel frame beam and column has suffered a lot of brittle damage in several earthquakes.Therefore,many experts at home and abroad began to study the connection of beam column with high-strength bolt.The beam-column connection with high-strength bolt is a new type of connection that connects the beam-column together with the top and bottom Angle steel,end plate,section t-shaped steel and other connecting parts through high-strength bolts.It has good bearing capacity and seismic performance,and this kind of connection can transfer certain shear force and bending moment,which is called semi-rigid connection,while the split-t-shaped steel beam-column connection is considered to be one of semi-rigid connections with high stiffness,which has good engineering application value.In this paper,with the support of national natural science foundation of China to study hysteretic performance,energy consumption characteristics and failure mode of the subdivision T steel beam-column connections under low reversed cyclic loading,and to study hysteretic performance,energy dissipation characteristics,buckling mechanism and failure mode of plane steel frame with the subdivision T steel connection and space steel frame under low reversed cyclic loading,and the mechanical characteristics of the t-shaped steel frame are simulated by finite element.The main research conclusions are as follows:(1)Three low-cycle repeated load tests and finite element numerical simulation are carried out by means of column end loading,and the influence of joint form and t-bar parameters on joint performance is studied.The results show that: For the joints in the frame,the larger the size of the divided t-shaped steel is,the larger the yield displacement,yield load and maximum load of the joints in the frame will be;The yield displacement,yield load and maximum load of the frame joint are larger than those of the frame beam-column joint for both the frame side node and the frame middle node using the same type of section t-shaped steel.The maximum strain of the joint of the section t-shaped steel joint occurs at the junction of the flange and web of the t-shaped piece,where plastic hinge is first generated.(2)The low-cycle repeated load test was carried out on a two-story flat steel frame connected by T section,which is found that there is no joint failure or other brittle fracture of the whole frame,and it has good deformation and energy dissipation capacity.The plastic hinge of the frame first appears at the connection between the flange and the web of T section steel.The energy consumption capacity of the bottom layer is greater than that of the top layer for two single-layer plane frames.(3)The finite element analysis of the planar steel frame of beam-column connection with t-shaped steel is carried out,and the following conclusions are obtained: the increase of t-shaped steel flange thickness has limited contribution to the increase of bearing capacity and lateral stiffness of the frame,but it can increase the ductility of the steel frame;The axial pressure has a great influence on the bearing capacity of the frame.When the axial pressure is taken into account,the bearing capacity and lateral stiffness are obviously reduced,and the ductility of the steel frame is also reduced.(4)By the low reversed cyclic loading test on the two-storey single-span and two-truss-space steel frame connected by section t-shaped steel,a preliminary study on the characteristics and failure mechanism of such a connection steel frame shows that the frame has good seismic performance and energy dissipation capacity,fills blank of pseudo static test on subdivision T steel space of semi-rigid connection steel frame,and provides certain theoretical basis for the application of engineering of subdivision T steel beam-column connections.(5)The basic steps of calculating the bearing capacity of semi-rigid beam-column connections are summarized systematically,and the basic steps of determining the bearing capacity of t-shaped steel beam-column connections by means of the component method are introduced emphatically,and based on the ultimate bearing capacity method,a second-order inelastic analysis method for semi-rigid connected steel frames is established.