damping of steel eccentrically braced frames in direct displacement-based design

Due to the limitations and deficiencies in the force-based design approach, several methods are introduced and examined in order to improve this methodology. however, over the years, researchers have proposed displacement-based design methods. among them, the direct displacement-based design (ddbd) method is one of the most thorough and accepted. the main goal of this method is to determine equivalent damping. considering the equivalent damping and target displacement corresponding to the desired ductility, the design base shear is obtained from the displacement spectrum. several methods are proposed to determine equivalent damping. in this study, the revised effective mass (rem) method is employed for the design of eccentrically braced frame (ebf) systems. using this method, equivalent damping is determined for ebf’s. an expression is proposed for determining the equivalent damping for ebf’s in term of ductility.