Combined stiffnesses for beam and column braces

Synopsis An approximate analysis is developed for uniformly loaded members braced at mid- length.  The primary member is replaced by a pair of axially loaded flanges, linked by the web in such a way that twist rotations and transverse flange displacements are coupled. The brace has both axial and bending stiffness, the latter being such as to restrain twist rotations of the primary member.   Closed form solutions are obtained for critical combinations of axial and bending brace stiffness.  The necessary values of axial and bending stiffness are shown to be linked by an equation which is of consistent form for all cases considered.