Research On The Overall Stability Performance Of High-Strength Welded Cross-section Beam-columns

With the rapid development of super high-rise and large-span structures,ordinary steel structure buildings can no longer meet the needs of people’s daily production and life.Therefore,in recent years,high-strength steel structures have been used more and more around the world,but my country’s high-strength steel structures The research work of this paper is not enough,especially the lack of research on the overall stability of high-strength welded steel beam-columns,so the rationality and reliability of the engineering design cannot be guaranteed.In this paper,the numerical simulation method is used to deeply study the overall stability of high-strength welded round steel pipes and I-shaped crosssection beam-columns of Q460 and Q690 steel grades.It is discussed whether it is safe to calculate the overall stability of high-strength steel beam-columns by the formulas of national codes,and then put forward reasonable design suggestions.This paper mainly does the following:（1）Firstly,the engineering application of high-strength steel is summarized,and the research status of the initial defect and residual stress of high-strength welded round steel pipe and I-shaped section is introduced.（2）The finite element software ANSYS is briefly introduced,and then the finite element model considering the initial defects is established by ANSYS software.The results obtained by the finite element model are compared with the experimental results collected in the literature to verify the validity of the finite element.（3）The calculation results based on the finite element are compared with the results obtained by the codes of various countries,and it is discussed whether the formulas given by the codes of various countries are too large or too small for the calculation of highstrength steel compressive members.It can be found that the Chinese steel structure code（GB50017）-2017)and the European Code for Steel Structures（EN1993-1-1）are too small,while the American Code for Steel Structures（ANSI/AISC360-16）is too large.（4）The data obtained by the finite element are compared with the data calculated by the Chinese steel structure standard（GB50017-2017）,the American steel structure code（ANSI/AISC360-16）and the European steel structure code（EN1993-1-1）,and verified the national steel structure.Whether the formula for calculating the overall stability of highstrength steel beam-columns is safe.（5）By comparing the finite element results in Chapter 4 with national codes,it can be seen that the overall stability of the beam-columns is related to the regularized slenderness ratio.By fitting the finite element data,a new high-strength steel beam-columns is given.Overall stable correction formula.Based on the above work,the main conclusions of this paper are as follows:（1）In this paper,ANSYS software is used to establish a finite element model of highstrength welded round steel pipes and I-shaped beam-columns.The model takes into account the influence of initial defects and residual stress.The results obtained by finite element are consistent with the existing experimental data results in the literature.The error is within the allowable range,which shows that the finite element model established in this paper can well simulate the buckling performance of high-strength welded round steel pipes and I-shaped beam-columns.（2）Through the analysis of the two parameters of slenderness ratio and eccentricity,it can be found that with the increase of slenderness ratio and eccentricity of the component,the overall stable bearing capacity decreases gradually.When the slenderness ratio of the component is greater than 100,the overall stable bearing capacity of the component is too small,which indicates that the material properties of the component cannot be fully utilized.When the eccentricity of the component is greater than 1,the overall stable bearing capacity of the component is very low,and the change of the slenderness ratio has less and less influence on its overall stable bearing capacity.（3）The calculation results based on the finite element are compared with the results obtained by the codes of various countries,and it is discussed whether the formulas given by the codes of various countries are too large or too small for the calculation of highstrength steel beam-columns.It can be found that the Chinese steel structure code（GB50017）-2017)and the European Code for Steel Structures（EN1993-1-1）are too small,while the American Code for Steel Structures（ANSI/AISC360-16）is too large.（4）Through a large number of finite element data analysis results,a new correction formula for the overall stability of the beam-columns is obtained by using the origin software.