$5\mathrm{.}31.$ An H $-$section beam with unequal flanges is subjected to a vertical load $\backslash ($ P $\backslash )($Fig$.$ P$5\mathrm{.}31).$ The following assumptions are applicable:

$1.$ The total resisting shear occurs in the flanges.

$2.$ The rotation of a plane section during bending occurs about the symmetry axis so that the of curvature of both flanges are equal.

Figure P$5\mathrm{.}31.$