Finite Element Studay On Aseismic Performance Of Weakened Jiojnts Of Reinforced Steel Frame Beams With Channel Steel

To solve the beam web plate round hole groove node seismic bearing capacity is insufficient,excessive stress deformation on the problem,this article put forward in the beam web plate hole area set up opening channel steel strengthening method,first by using the finite element software ANSYS simulation analysis of the channel steel strengthening beam web weaken type node under the action of static loads is drab,circulation of seismic performance,and with standard for design of steel structure in our country in the recommended way of reinforcing the contrast analysis,finally to further verify the channel steel strengthening web opening round hole nodes in seismic behavior under seismic load,set up three : F-BASE(web not weakened),F-RBW-base(web weakened but not strengthened),F-RBW-U(channel steel reinforced)three-layer steel frame structure model,the bearing capacity and dynamic characteristics of three steel frame structures with different node forms under dynamic load are studied,and the following conclusions are drawn:1)under the action of monotone and cyclic static load,channel steel is set in the hole of the plate,and the ultimate bearing capacity,initial stiffness and energy dissipation capacity of the node are greatly improved compared with that of rbw-base;The specimens with proper arcweakening of upper and lower flange and web of channel steel have lower stiffness degradation rate,more full hysteresis curve and the largest total energy dissipation coefficient than those without or with improper arc-weakening.The bearing capacity,initial stiffness and energy dissipation performance of the specimens with the same weakening position of channel steel rl and the weakening depth c all increased with the increase of channel steel thickness t.When the strength grade of channel steel is higher than that of steel beam,the energy dissipation capacity of members in the peak displacement stage is significantly reduced.2)through the casing with our specification recommended,ring stiffener,annular plate reinforcing method comparison,found that the bearing capacity of the channel steel strengthening way node,ductility,stiffness degradation rate,hysteresis properties are seismic performance is superior to casing,ring stiffener,annular plate reinforcing method,is a recommended way of strengthening.Among the three reinforcement methods recommended in the specification,it is recommended to choose casing reinforcement first,followed by ring stiffener.As ring plate reinforcement method does not make plastic hinge move from the beam end,it is not recommended to use this method.3)for F-BASE(web not weaken),F-RBW-BASE(web weaken not reinforcement),F-RBW-U(channel steel reinforcement)three different nodes in the form of a steel frame structure under dynamic load mode,BASE shear,interlayer displacement contrast found that three models of the first three order vibration mode shapes are basically identical,steel frame is not because of the steel beam web weaken or split hole area to strengthen and change of the structure of the vibration mode;The reinforced f-rbw-u steel frame has a small dynamic response of base shear and interlayer displacement under seismic load,and has good seismic performance.