Overall Bending Stability Behaivor Of Q690 Welded H-shaped Section Beams

At present,the research of high-strength steel members is mainly focused on axial compression members and eccentric compression members,while the research of bending members is rarely involved.In this paper,considering the current research progress and the existing codes in various countries of high-strength steel,experimental study and finite element analysis were carried out to investigate the overall stability of Q690 high-strength steel welded H-shaped cross-section beams.A comparative study on the calculation method of the overall stability of Q690 high strength steel welded Hsection beam were also carried out.The research content of this article includes:(1)Bending stability tests were carried out on four specimens of Q690 high strength steel welded H-section beams.Through the analysis of failure modes and corresponding performance indexes,the overall stability of specimens with different section sizes and pure bending lengths was compared.Based on the Q690 material property datas obtained from the material property tests,and the calculation formulas of Chinese,American and European steel structure codes,the critical bending moment of each specimen was calculated.Compared with the test results,it is found that the Chinese code was the most in accordance with the test results,the American code was unsafe,and the European code was conservative.(2)A finite element model was built using the finite element software ABAQUS.Compared with the experimental results,the accuracy of the finite element model was verified.So the finite element model can objectively reflect the overall stability of the Q690 beam.(3)The sensitivity of the overall stability of Q690 high strength steel welded Hsection beams to the parameters such as aspect ratios,initial geometric imperfections,residual stresses and position of lateral supports was studied by numerical simulation.(4)The parametric analysis results were compare with GB 50017-2017,EN 1995-32005 and ANSI / AISC 360-16.It is found that the curves given by the Chinese and European regulations tend to be conservative.EC3 specification is the most conservative with the largest deviation,the Chinese specification has the smallest deviation,and the American specification is unsafe when the beam is loaded at three points.Finally,the applicability of the calculation methods of specifications in different countries to the overall stability of the Q690 high-strength steel beams was discussed.