Overall Stability Behavior And Design Method Of Q460 High Strength Steel Welded I-Section Overhanging Beams

At present,the research on high strength steel(HSS)bending members are mostly centralized on simply supported beams and two-span continuous beams.Compared with normal strength steel,HSS has excellent advantages and wider application prospect.To study the overall stability performance of Q460 HSS welded I-section overhanging beams and refine the corresponding provisions of codified specifications,with initial geometric imperfections and residual stresses measured ahead,an experiment under concentrated loads was conducted on nine overhanging beams with various top flange strengthened section forms and overhanging span length ratios.Test results indicate that the ultimate moment of the test beams declines with the ascending overhanging span length ratio,and effect of overhanging span length ratio on the ultimate moment of overhanging beams is relatively lower compared with that of top flange strengthened when the critical section of test beams is positioned at the main span.Then,the finite element analysis software was used to model the specimens containing measured initial geometric imperfections and residual stresses.It is found from the test results that the finite element analysis model can accurately simulate the test.Finite element analysis models,correlated well with test results,were applied to examine the effects of various parameters on the ultimate moment of overhanging beams.On the basis of the eigenvalue buckling analysis results and the formulas for the elastic moment of simply supported beam stipulated in Design code of steel structures(GB50017-2017),the calculation formulas of elastic critical moment for overhanging beams were obtained by regression.The design method for the global stability of Q460 HSS welded Isection overhanging beams were proposed based on the test results and finite element analysis results.Moreover,the reliability of calculation method for determining the ultimate bending moment of Q460 HSS welded I-section overhanging beams were assessed by means of a reliability analysis in accordance with GB50068-2018.