DESIGN OF TRANSVERSELY STIFFENED WEBS OF I-BEAMS

The design rules for webs in shear given in the limit states British and Australian steel standards are reviewed. The semi-analytical complex finite strip method of buckling analysis is then used to obtain the elastic local buckling coefficients of the webs of I-beams subjected to shear when the restraint provided by the flanges is included. It is shown quantitatively how the flange restraint increases the local buckling coefficient above the value for a web with simply supported edges, the latter forming the basis of the strength rules in the present standards. The use of the rationally-derived local buckling coefficients to enhance the strength of webs in shear implicit in the design standards is then described. Use of these local buckling coefficients should lead to economies in steel.