Bending of Deep Girders with A514 Steel Flanges

An investigation was conducted to determine the maximum web slenderness that could be safely used in homogeneous and hybrid girders with A514 steel flanges. An experimental study included tests of four 39-in-deep girders: two pairs of girders in which each pair consisted of a hybrid and a homogeneous girder. The tests showed that the present design formula for a reduced flange stress due to a nonlinear web stress can be applied to homogeneous A514 steel girders, whereas for hybrid girders with A514 steel flanges and A36 steel webs this reduction is not required provided that the effect of web yielding is considered. A theoretical model of the vertical-buckling phenomenon treats the compression flange and a portion of the web as a column elastically supported by the web and subjected to vertical buckling between transverse stiffeners. Design criteria are suggested, for transversely stiffened girders with A514 steel flanges subjected to pure bending, to insure that the flange-yield moment can be reached without vertical buckling.