SUMMARY
A practical application of ‘beam on nonlinear Winkler foundation’ approach has been utilized in this paper for a case study on seismic performance of concrete shear wall frames to assess the soil–foundation–structure interaction effects. A set of 3-, 6-, 10- and 15-story concrete shear wall frames located on hypothetically soft, medium and hard soils were designed and modeled using the OpenSees platform. The numerical model of each frame was constructed employing the distributed and lumped plasticity elements as well as the flexure–shear interaction displacement-based beam–column elements incorporating the soil–footing interface. Pushover analysis was performed, and the results were studied through two code-based viewpoints: (a) force-based design and (b) performance-based design. A comparison was made afterwards between the frame behaviors in the fixed-/flexible-base conditions. The results indicate some degree of inaccuracy in the fixed-base assump-tion, which is regularly applied in analysis and design practice. The study emphasizes on how the fixed-base assumption overestimates the design of the wall element and underestimates the design of the connected moment frame