A simplified methodology to determine damping for special concentrically-braced frames

Abstract

There are two approaches most widely used in the literature to determine damping: steady-state harmonic excitation and the earthquake excitation approach. Using these approaches, different expressions have been developed to determine damping of structures based on various hysteretic models and ductility levels. In this paper, a simplified methodology is proposed for the determination of the damping of SDOF systems, in particular, special, concentrically-braced frames. This new method, based on revised effective mass, uses both of the above approaches to determine the damping. Using this method, damping is determined for special inverted V and X braced frames. Two expressions are proposed for determining the damping for special, concentrically-braced frames in terms of ductility and slenderness ratio.