Abstract
Local buckling of beam and/or connection elements is a source of softening in the moment-rotation behavior in certain connections. This effect can significantly reduce the maximum load-carrying capacity of steel structures. In this study, an elastic-plastic plane frame analysis which includes the effect of nonlinear connection behavior is presented to predict the ultimate load-carrying capacity of steel frames. The structural model comprises members which are assumed to behave elastically with nonlinear connection moment-rotation behavior. The main objective of this study is to investigate the effect of connections which exhibit strain-softening behavior on the ultimate strength and stability of flexible frames. Numerical studies of frames made using the developed computer program are presented. Observations regarding the effects of flexible connections on the strength and deflection of steel framed structures are discussed. The proposed analyses procedure using flexible joints modeled by the Richard function were found to be simple and accurate which compared to elastic-perfectly plastic models.