Investigation On Anti-collapse Performance Of Honeycomb Composite Beam-column Substructure

The continuous collapse of a building structure is a chain reaction caused by a large area or overall damage caused by local failure at a certain location.Once such damage occurs,it will inevitably cause huge losses of human life and property.When a part of the vertical load-bearing member of the structure fails,in the small deformation stage,the beam mechanism is mainly used to resist the external load.In the large deformation stage,the structure mainly depends on the catenary mechanism to provide resistance.The current research on the collapse resistance of the frame structure is mostly concentrated on the solid-web composite beams,but the research on the honeycomb composite beams is quite insufficient.Under the action of external loads,the honeycomb beam holes and beam piers are easy to form after the honeycomb beams are opened.Stress concentration will inevitably affect its anti-collapse performance,so it is necessary to study the anti-collapse performance of the frame structure using honeycomb composite beams in order to obtain reasonable design indicators.Based on the alternate load path method and the monotonic static loading method,the two composite beam column structure specimens connected by bolting and welding were tested respectively,and the weakening of the honeycomb beam web to the collapse resistance of the substructure was analyzed.The results show that the two specimens have experienced six main stress stages:elastic stage,elastic-plastic stage,arching effect stage,plastic stage,transition stage and catenary effect stage.With high initial stiffness,plastic hinges are easily formed at the beam piers when the steel beam webs are properly opened,so that the honeycomb composite beam specimens have better shape-shifting ability and the catenary mechanism can be more fully exerted.Using finite element software of ABAQUS,the numerical analysis models of solid web composite beam-column structure and honeycomb composite beam-column structure are established respectively,and the experiment is compared with finite element on four aspects of load displacement curve,failure mode,internal force and resistance mechanism.The analysis results that the numerical results are in good agreement with the test,the refinement numerical simulation method has high accuracy,it can be used as structure of honeycomb composite beams pillars collapse resistance in-depth study of the important means.In this paper,the parametric analysis of the column structure of bolted welded honeycomb composite beams is carried out.firstly,the influence of the porosity on the collapse resistance of honeycomb composite beams is studied by analyzing the load-displacement curve,the internal force development curve and the resistance mechanism.the results show that when the porosity is between 60%and 70%,the substructure has better collapse resistance.Secondly,the influence of hole spacing on the collapse resistance of the substructure is studied.After analysis,the paper suggests that the hole spacing of honeycomb composite beams should be between 1.0 H and 1.4H.Thirdly,the influence of hole spacing is studied,and the results show that the proper hole spacing can cause the plastic hinge to move out at the joint point,and in order to avoid the web tearing at the first hole at the beam end,the hole spacing should not be less than one time of the beam height.Finally,the influence of the floor reinforcement ratio is studied.The results show that the floor reinforcement ratio has little influence on the initial stiffness of the substructure,but significant influence on the catenary mechanism.