Overall stability behavior and design method of Q460 high strength steel welded I-section overhanging beams

Abstract

To investigate the overall stability behavior of Q460 high strength steel (HSS) welded I-section overhanging beams and develop the corresponding design method of codified specifications, nine overhanging beams with various top flange strengthened section forms and overhanging span length ratios were tested under concentrated loads. The initial geometric imperfections and residual stresses were measured in advance. Test results indicate that the overall stability capacity of the specimens decreases with the increase of overhanging span length ratio and top flange strengthened has a greater effect on the overall stability capacity of overhanging beams than overhanging span length ratio when the dominative stability segment of specimens is located at the simply supported span. Finite element analysis (FEA) models verified by test results were established to examine the effects of load form, load ratio, section form, height-to-width ratio, simply supported span length and overhanging span length ratio on the overall stability capacity of Q460 HSS welded I-section 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. Furthermore, the calculation formulas of ultimate bending moment for Q460 HSS welded I-section overhanging beams were proposed based on the obtained formulas for elastic critical moment of such beams, test results and nonlinear buckling analysis results.