Analysis Of The Ultimate Bearing Capacity And Hysteresis Performance Of H-steel-square Branch T-join

Steel structures are widely used in airport terminals,stadiums,offshore platforms,and high-rise buildings due to their excellent mechanical properties,convenient processing and fabrication,and easy to create cross sections.As an important part of steel structures,joints affect the bearing capacity and energy consumption capacity of the structure.In practical engineering,the problem of insufficient bearing capacity of joints often occurs.In addition,in the past half century,earthquakes have occurred frequently around the world,and there are not a few cases of steel structures being damaged in earthquakes,and most of the damage is caused by initial node damage.It can be said that the response of joints under earthquakes determines the overall seismic performance of the structure,Therefore,it is necessary to evaluate the mechanical properties of joints by studying their ultimate bearing capacity and hysteretic behavior.This paper studies the ultimate bearing capacity and hysteretic behavior of H-shaped steel square branch T-shaped intersecting joints through finite element analysis.The main contents of the study are as follows:Verification of the finite element model.After fitting the hysteretic curve and skeleton curve obtained from the finite element analysis with the experimental results,it is found that the finite element results agree well with the experimental results as a whole,indicating that the established finite element model is correct.This provides a basis for the subsequent parametric analysis of the ultimate bearing capacity and hysteretic behavior of joints using finite element software.Ultimate bearing capacity study.The finite element models of 64 unreinforced joints are designed and analyzed using Abaqus software.After completing the analysis,the load-displacement curves of each model are obtained.First,the ultimate bearing capacity of each node is obtained using the ultimate strength criterion,and then the effects of geometric parameters such as the ratio of branch pipe width to main pipe flange width(β),the ratio of branch pipe thickness to main pipe flange thickness(γ),and the ratio of main pipe flange width to thickness(η)on the ultimate bearing capacity of the joint are analyzed,Then,the ultimate bearing capacity calculated by the European code formula is compared with the finite element results,and a multiple linear regression fitting is performed using Origin software to obtain a recommended formula for calculating the ultimate bearing capacity of such T-joints.Finally,the failure mode and distribution rule of the joints are analyzed.Hysteresis performance study.A finite element model of 36 unreinforced and reinforced joints was designed,which was divided into three types of specimens: non stiffened,with stiffened ribs,and filled with concrete in the stiffened ribs.There were three groups of specimens for each type,with four in each group;After obtaining the hysteretic curve through finite element software analysis,based on this,the effects of geometric parameters on the hysteretic curve of the specimen,the skeleton curve,stiffness degradation,and the cumulative energy dissipation coefficient are analyzed.The failure mode of the joint is analyzed through stress nephogram to study the hysteretic performance of the joint.