Inelastic Behavior of X‐Bracing in Plane Frames

Abstract

A numerical procedure for determining the hysteretic behavior of axially loaded, pin‐ended bracing members is outlined. The relationships between axial loads and deformations are computed recognizing the different states corresponding to appropriate load‐displacement conditions covering both buckling and yielding. Accurate numerical representation of the hysteretic response curve of bracing members is confirmed. By incorporating bracing elements in representative elastic rigid‐jointed plane frames, the contribution of braces to lateral load resistance in seismic excitation conditions is examined using numerical integration techniques. The efficiency of bracing systems is demonstrated. Both the lateral displacements and the loads induced in the main frame are less than those in the equivalent unbraced structure. Accurate prediction of post‐elastic behavior of bracing members has significant practical application potential particularly in industrial structures where the concept of an initially stiff yet structurally efficient system capable of degrading under extreme lateral loading conditions to a more flexible, but still load resistant structure, is very attractive.