Seismic assessment of mid-rise reinforced concrete buildings is important for urban seismic risk reduction. Nonlinear time history analysis is the state-of-the-art analysis tool for this purpose. However, the number of such buildings may reach to several tens of thousands in metropolitan cities of earthquake prone countries. This necessitates faster yet sufficiently accurate assessment methods to mitigate the seismic risk. In this study, a simple and efficient approach is developed and validated for the assessment of such buildings. The proposed method relies on estimating the reduced secant stiffness values for structural members based on elastic analysis. Afterwards, subsequent elastic analyses with the reduced stiffness values is conducted employing the equal displacement rule. The procedure is tested for twelve buildings with and without shear walls, and torsional irregularity. The member end chord rotation results obtained with the proposed procedure are compared with the mean results of eleven nonlinear time history analyses. It is found that the proposed procedure can estimate column and beam chord rotation demands with reasonable accuracy, significantly reducing the computational time.