High-strength steel: implications of material and geometric characteristics on inelastic flexural behavior

New developments in steelmaking have enabled high-strength steels to be produced which have exceptional toughness and weldability, making the material appealing for structural design applications. In earthquake resistant design, where members are expected to deform inelastically, it is imperative that these members possess adequate ductility. This paper discusses the mechanical characteristics of the new high-strength steels and reviews existing US compactness criteria for flexural members. The effects of web and flange slenderness, material stress-strain characteristics, and axial load on ductility capacity of flexural members are presented. Based on recent research, the extrapolation of current US compactness criteria to higher strength steel is shown to overestimate flexural ductility capacity. In addition, the yield-to-tensile strength ratio of the material is shown to have a significant influence on ductility and energy dissipation capacity under cyclic loading, suggesting that a limiting value should be used in order to ensure acceptable behavior under earthquake loading. (C) 1997 Elsevier Science Ltd.