Inelastic Hysteresis Behavior of Steel Bracing Members and Seismic Behavior of Braced Frames

摘要

A modeling study of the hysteresis behavior of several steel braced frames subjected to severe earthquake motion is reported. Preliminary investigations were conducted to develop appropriate methods for computing the inelastic dynamic response of complex structures. The theoretical study utilized a model to represent a bracing member. Results show that optimum post-bucking behavior is obtained when yielding occurs simultaneously in the connections and at mid-length of the member. This study of bracing members identified the effective slenderness ratio as being the most influential parameter in determining their hysteresis behavior. Experiments also demonstrated that differences in static and dynamic hysteresis loops are increased, and that experimental hysteresis loops compare well with theoretical results. Based on these member studies, a mathematical model and a physical model were developed to computer the response of braced frame structures to severe earthquake motion. These two models have been programmed for use with the DRAIN-2D program. Nonlinear building response by the characteristics method and studies of torsion in 3-dimensional structures are described.