Evaluation of the ductility features in steel structures with softening moment-rotation behaviour based on a nonconvex optimization formulation

Abstract

In order to determine the ductility features of steel structures, several approaches have been introduced in the bibliography. In this paper a certain method is proposed which considers the actual form of the moment-rotation curve, including the possible softening branches. Moreover, stability phenomena are also taken into account as they significantly influence the overall response of the structure. For the effective application of the considered method, a solution algorithm was developed, mainly based on the nonconvex optimization theory. The numerical applications that follow demonstrate the applicability of the adopted approach.