Assessment of the Seismic Performance and the Base Shear Contribution Ratios of the RC Wall-frame Dual System Considering Soil–Structure Interaction

Soil–structure interaction (SSI) effects on the dynamic response of reinforced concrete (RC) wall-frame dual system have not adequately been investigated and are usually not considered in the engineering practice. In this study, the seismic behavior of the RC wall-frame dual system is studied in detail. The main goal of this research is to obtain the base shear contribution ratios of the dual system components including shear wall and moment-resisting frame with and without considering SSI effects. For this purpose, three 5-, 10- and 15-story structures are modeled and analyzed in OpenSees platform. For each model of the structures, pushover analysis, and 22 nonlinear dynamic time-history analyses assuming 11 ground motion records and 2 levels of PGA = 0.4 g and 0.7 g are performed once by considering SSI effects and once without it. For more accuracy, the shear–flexure interaction (SFI) model is used to imitate the actual behavior of the RC shear wall. The beam on the nonlinear Winkler foundation (BNWF) method is utilized for modeling SSI effects. The results indicate that considering SSI effects leads to an increase in the fundamental periods of all models and the base shear contribution ratios of the moment frame, whereas it leads to a decrease in the base shear contribution ratios of the shear wall. On the other hand, the SSI effects increase the inter-story drifts in all models. However, when the structures subjected to ground motion, records with PGA = 0.4 g and 0.7 g meet the life safety and the collapse prevention performance levels, respectively.