The work presented here concerns the assessment of the corrected equivalent viscous damping coefficient for concentric braced steel frames, referring to the direct displacement based design method (DDBD) described at Section 3. First, concentric braced steel frames and displacement based design are described, with particular attention given to the evaluation of the damping coefficient. The models realized to perform non-linear analysis and the procedure used to determine the corrected equivalent viscous damping coefficient are then described (Sections 4 and 5). Finally, the results obtained through non-linear dynamic analysis are presented and used to propose a relation between the damping coefficient, the slenderness of braces and the ductility level.