Study On The Collapse Resistance Of Reverse Channel Joint Based On Column Removal Scenario

With the development of civil engineering,steel structure system has been used more widely.The design of steel structure buildings under the normal loads is more complete in the engineering field.However there are some worth discussing about the progressive collapse behavior caused by sorts of accidental loads.The structure progressive collapse is caused by part failure which leads to the transmission of damage among structural members,and leads to a large-scale or whole collapse which is disproportionate to the initial failure.When a building is seriously damaged,the deformation of the joints in the building structure is usually quite large,failure to deform the local node often leads to widespread or total collapse.Therefore,the subject that is about the mechanical properties of holding under distortion,failure modes and the progressive-collapse resistance needs to be studied further.The reverse channel connection were analyzed through the pseudo-static nonlinear numerical simulation analysis of collapse resistance by using ANSYS/LS-DYNA finite element software based on the demolishing component analysis method,and the mainly studied aspects were as follows:(1)The numerical simulation analysis of reverse channel connection considering material failure strain is carried out.From the data simulation and experiment,the failure shape,bending curve and displacement curve and so on,the data simulation results are consistent with the experimental results.Verify the validity of the simulation method.This thesis analysis of the contract in the process of progressive collapsed internal force to reveal the situation change in the process of progressive collapse mechanics,and discuss the rules of development and transformation mechanism of the Centre still mechanism and Catenary mechanism of collapsing process.(2)Parameterized analysis was conducted on the progressive-collapse resistance performance of reverse channel joints.It discussed the effects of the programme’s own resource parameters on the ultimate joint sustainability,the development of internal strength and the resistance mechanism.The results show that increased SDR will increase the axial strength of the beam,and will increase the contribution of the sebum mechanism,while the ultimate bearing capacity will decrease.However,the span-depth ratio has less influence with final failure pattern of the node.The comprehensive analysis shows that the reverse channel steel joints have good deformation performance,which can avoid the premature failure of the main beam joints,and extend the end-plate connection to provide higher resistance.The catenary action can be developed more fully with a wide channel connection.(3)Based on the Izzuddin energy method,the dynamic response of the study nodes was analyzed,and the dynamic increase factor was calculated in this thesis.With the increase of the displacement of the failure column,the(Dynamic increase factor)DIF_P based on force decreases gradually.With the increase of the failure column load,displacement on the basis of DIF_U gradually increases.Dynamic increase factor is greater than specification specs for dynamic,dynamic increase factor increase factor of specification should be conservative.It is suggested that the DIF_P of the structure in this paper should be 1.3 because the study on progressive collapse is on the mechanical performance of the structure at large deformation stage,DIF_U recommended value 2.8.