Highly Ductile Limits for Deep Steel Columns

Abstract

The collapse behavior of individual deep columns subjected to realistic loading and boundary conditions is investigated in this study. Loading protocols that are representative of seismic demands on first-story columns are developed through simulations of complete frames subjected to collapse-inducing seismic loading. A set of deep columns that cover a wide range of both global and local slenderness ratios representative of commercially available deep sections is used to investigate and codify the effects of three key parameters: level of axial loading, global slenderness (L/ry), and web slenderness (h/tw). Current design recommendations are critiqued and modified provisions that incorporate the influential parameters identified in this study are proposed for designing highly ductile members for seismic applications. The new provisions are proposed in a format that can facilitate adoption into future specifications.