Stability of nonsymmetric cross-bracing systems

When a lateral force acts on a cross-bracing system, one brace member is subjected to a compressive force while the other is subjected to a tensile force. The tension brace provides a restraint to its compression counterpart at the point of intersection, if they are connected. This interaction of braces reduces the effective length of the compression brace member and should be taken into consideration to avoid overconservative designs. This paper presents a numerical method based on the energy principle for the determination of buckling load and effective length factor of the compression brace member. Typical design charts are given for a quick estimation of the effective length factors. Moreover, closed-form solutions are presented for the special case of symmetric brace systems