A simplified method to determine seismic responses of reinforced concrete moment resisting building frames under influence of soil–structure interaction

As the Iranian seismic code does not address the soil–structure interaction (SSI) explicitly, the effects of SSI on RC-MRFs are studied using the direct method. Four types of structures on three types of soils, with and without the soil interaction, are modeled and subjected to different earthquake records. The results led to a criterion indicating that considering SSI in seismic design, for buildings higher than three and seven stories on soil with Vs<175 m/s and 175