Study And Application On The Existing Steel Frame Structure With Weakened Section

At present,in the field of construction,countries around the world pay more and more attention to the development of environmental protection.Compared with the traditional reinforced concrete structure,masonry structure and other structures,steel structure has many advantages such as high strength,light weight,good seismic performance and recyclable materials,which are widely used in construction projects.However,steel structure will be affected by environmental factors(such as atmospheric corrosion and chemical corrosion)in the process of long-term use,the effective section of structural members will be weakened,which will reduce the bearing capacity under various external loads,resulting in greater impact on the safety in use,while the stability of steel structure often determines the bearing capacity,so the study of section cutting The stability of weak steel frame is very important.This paper mainly studies the stability of steel frame under the joint action of vertical load and horizontal load under the condition of weakened section.By reducing the thickness of the bottom column flange,the thickness of the bottom column web,the thickness of the bottom beam flange,the thickness of the first and second layer column flange,the damage of the existing steel frame section is simulated,and the theoretical analysis is carried out by using the finite element method,And the scale model test is carried out,and the main contents are as follows:(1)The finite element analysis model of full-scale steel frame structure is established.The linear elastic stability analysis and nonlinear buckling analysis of 16 analysis models under 6 working conditions are carried out by using ABAQUS software,and the change of stability bearing capacity of steel frame structure under different weakening degree of beam and column sections at different parts is studied;(2)According to the model similarity theory,the scale model of the structure is designed,and five kinds of steel frame test models of the weakening degree of beam and column sections are designed and manufactured.The static load test of the model under the combined action of vertical load and horizontal load is completed,and the change of bearing capacity is studied;(3)Theoretical analysis and test results show that when the beam section of steel frame structure weakens,the bearing capacity of steel frame structure decreases with the increase of the weakening degree of the beam section,which shows that the weakening of the beam section has little effect on the stability of the structure.When the column section of the steel frame structure weakens,with the increase of the degree of the column section weakens,the bearing capacity of the steel frame structure decreases significantly,which shows that the weakening of the column section has a great influence on the stability of the structure.Therefore,the stability analysis of the structure with the weakened section should be carried out,and the structure should be strengthened to ensure the safety of the structure.