Bracing Requirements for Inelastic Steel Beams

The design of bracing for inelastic steel beams is seen to depend on the fulfillment of three separate criteria, that is, axial strength, axial stiffness and bending strength, and stiffness with respect to the longitudinal axis of the beam being braced. Equations are presented which allow each of these criteria to be individually defined. The application of the equations is simple and their predictions are in accord with the few test results which are available. The bracing equations are presented in such a way that they may be directly coupled with deformation capacity predictions contained in earlier papers by the writers. It is shown that the most essential property for the majority of practical brace systems is that they should possess adequate axial strength and stiffness. A basic assumption is that the far ends of the braces are rigidly held. The design force in the brace is found to be close to the currently used estimate of 2% of the beam flange force.