Study On Continuous Collapse Resistance Of Beam-Column Node Substructure Of Steel Frame With Reversed Channel Connection

During the normal use of steel structures,they may be affected by various accidental loads such as earthquakes,explosions,and fires,leading to structural collapse.Collapse accidents are usually accompanied by significant casualties and property losses.Beam column structure is the key part of the frame structure,and its deformation and bearing capacity play a key role in the structure’s resistance to progressive collapse.The use of reverse channel steel to connect beam column structures can provide good rotational and deformation capabilities for beam column joints.However,further research is needed on the mechanical properties of reverse channel steel joints in the event of column failure.Therefore,this article applies ANSYS/LS-DYNA finite element software to study the mechanical properties of reverse channel steel connected steel frame beam-column joints under column failure,mainly including the following content:(1)Establish finite element models of reverse channel steel nodes and bolted connection nodes,and assign three-dimensional fracture models to each component.Analyze the bending and rotation resistance of the reverse channel steel node under the failure condition of the central column,as well as the continuous collapse resistance of the bolted connection node.Compare the deformation map,stress cloud map,bending moment rotation curve,and load displacement curve obtained from numerical simulation with the experimental results,and verify the accuracy of the finite element model of the reverse channel steel node and the bolted connection node given a three-dimensional fracture model,And the correctness of using simplified hinge support boundary conditions during simulation.(2)Select reverse channel steel nodes with the same thickness as the flange and web of the channel steel,and parameterize the reverse channel steel nodes by changing the width of the channel steel,the thickness of the channel steel and the end plate.Analyze the failure mode,deformation form,total bearing capacity,and resistance mechanism of the reverse channel steel nodes under different parameters.Finally,propose reasonable recommendations for the various dimensions of the reverse channel steel nodes.(3)Using the Izzuddin energy method,the dynamic response of the reverse channel steel connection node at different channel steel heights was calculated,and its dynamic amplification coefficient was calculated.Analyzed the variation of the dynamic amplification coefficient of nodes with different channel steel widths,and provided recommended values for the dynamic amplification coefficient of reverse channel steel nodes based on force and displacement.