SUMMARYThis paper rigorously assesses the efficiency of viscous dampers connecting two walls to result in âviscously coupled shear wallsâ. This assessment also holds for viscous dampers in wall structures as they are mounted on frames parallel to the walls leading to âwallâviscous frameâ systems. A continuum approach is adopted to model the structure so as to enable nonâdimensional formulation of the governing equations. Those equations reveal that, under the approximations considered, the system damping ratio (defined here by 0.5 sqrt(c^2/(m*EI))) is a convenient compact single parameter controlling the response reduction w.r.t. the response of the corresponding undamped system. In contrast to coupled shear walls, this controlling parameter does not depend on the height of the building; therefore, the viscously damped system is efficient for lowârise buildings as well. The continuum approach also allows a semiâanalytical solution of the eigenproblem in the complex domain followed by a complex modal spectral analysis. Those solutions reveal the efficiency of the added damping in reducing not only the displacements, interâstory drifts, and wall moments but also the absolute accelerations, wall shear, total shear, and total overturning moments. The results of the analyses and the nonâdimensional tables and graphs developed for important response parameters lead to a simple method that could easily be implemented in practice for the purpose of initial design. Copyright © 2012 John Wiley & Sons, Ltd.