Simplified method for calculating dynamic characteristics of soil-isolated structure system

A simplified analysis model of base-isolated structure considering soil-structure interaction (SSI) is proposed based on an SR (sway-rocking) model. Rigorous and closed-form formulas for dynamic characteristic parameters are derived. In essence, the proposed methodology is an important extension of the simplified methodology for the case of non-isolated structures. The results of the proposed methodology were compared with the corresponding ones of the relatively rigorous complex eigenvalue approach with examples. And the results of comparison indicated that the proposed formulas can be applied in most engineering site conditions. However, the proposed method is more simple and practical. It is also shown that the SSI effects are more pronounced for high-rise structures in comparison to the low-rise ones. The proposed methodology can provides a concise and effective way of evaluating SSI effects on isolated structures in the schematic design phase, laying the groundwork for the study of the design method of isolated structures considering soil-structure interactions.