Effect of gravity columns on mitigation of story drift concentration for concentrically braced steel frames

Concentrically braced frames (CBFs) are among the most cost-effective systems and very commonly adopted in earthquake-prone regions (for example, Tremblay 2001, Marino & Nakashima 2006). An extensive survey of brace tests (Tremblay 2002), however, indicates that typical steel bracing members exhibit limited energy dissipation and severe degradation of resistance, and CBFs are prone to form a story-collapse mechanism after buckling of the braces (Tremblay 2001, MacRae et al. 2005).