Study On Mechanical Properties Of Openings Of Casing Reinforced Beam Webs In The Failure Of Middle Column

The most critical part of the frame structure resisting continuous collapse is the beam-column joint.Under the failure condition of the middle column,the monolithic load of the beam-column joint will produce obvious axial force effect,so that the structure passes through the catenary.The effect continues to resist vertical loads,and the deformation bearing capacity and rotational capacity of the beam-column joints are important indicators for predicting the collapse resistance of the frame structure.The opening of the casing reinforced beam web has been proved in the relevant seismic research.It can meet the plastic hinge external displacement under the reasonable opening parameters,effectively protect the beam-column weld joint area,and has good deformation bearing capacity.It allows the pipelines of different locations to pass through,saving construction space and making it easy to check and repair.The performance research of this kind of nodes under the failure of the middle column is still lacking.Therefore,this paper studies the nodes and compares them with the opening nodes and basic nodes of the web.Firstly,the finite element software ABAQUS is used to establish a refined model of all nodes considering material fracture,and the existing experiments are used to verify the rationality of the finite element method.The results show that the selection of suitable fracture parameters can effectively simulate various beam-column failure phenomena,and the simulation results are in good agreement with the experimental results.Secondly,according to the difference of the aspect ratio,the nodes are divided into three groups.The basic nodes,the typical opening nodes and the casing reinforcement nodes are selected for the node with the height ratio of 8 to analyze the performance of the nodes.Mode,bearing capacity,deformation and rotation ability,beam internal force and resistance mechanism development.Finally,the comprehensive analysis of all nodes under different span ratios and opening parameters is carried out to study the influence of opening parameters and span-to-height ratio on the deformation bearing capacity and resistance mechanism development of nodes,and the opening parameters of nodes with different span ratios.The scope provides reasonable advice.The analysis proves that the opening of the casing reinforced beam web improves the bearing capacity and ductility of the joint without reducing the resistance of the bending mechanism of the joint,effectively preventing the premature cracking of the joint,promoting the development of the resistance of the joint suspension mechanism and improving The frame structure is resistant to collapse.Reasonable opening parameters have a great influence on the ductile failure and ultimate resistance development of the joint,and the beam span height ratio has a significant influence.The larger the span ratio is,the faster the suspension mechanism plays,and the later the cracking of the joint.