Ultimate strength interaction of stiffening steel box girder in cable-supported bridges

摘要

Wide flange box type steel cross-sections are widely adopted as stiffening girders in cablesupportedlong span bridges due to their relatively light self-weight, superb torsional rigidity andaero-elastic performance. Those stiffening girders are supposed to resist externally applied bendingmoment as well as compressional forces in longitudinal direction transmitted from inclined cables.Ultimate strengths are interactively determined as ultimate flexural strength is affected by appliedaxial compressive forces and ultimate compressive strength is affected by applied flexural moment.Effect of strength interaction between bending and compression are investigated for wide flangetype steel box girders in this study. Wide flanges are stiffened with U-shaped stiffeners that are alsocalled U-ribs. To evaluate the interaction effect, nonlinear incremental analysis techniques are fullyutilized for hypothetical numerical models. Initial imperfections and residual stresses are alsoincorporated in the analysis. Strength interaction curves are compared with existing codes for thepurpose of practical strength design for wide flange steel box girders in cable-supported bridges.