A procedure that can be used for preliminary seismic analysis of intake-outlet
towers including soil-structure-water interaction is developed. The formulation also considers the effect of partial soil-foundation separation, a phenomenon of considerable interest for the design of such systems that has not been addressed in the literature. The hydrodynamic pressure of the water is accounted for through added masses given in concise closed-form expressions for easy use in analysis and design. The nonlinear equations of motion, based
on foundation-soil bond conditions, are solved numerically. The effects of soil-structure-water interaction are evaluated for a representative intake-outlet
tower. Parametric studies are also conducted in the presence and absence
of surrounding and contained water for typical cases of soil conditions and tower height-foundation width ratios. The results indicate that hydrodynamic
effects are significant and cause an increase in deflections, moments and shears and a decrease in foundation rotation. The study shows that for short
towers, foundation uplift is unlikely to occur. On the contrary for slender towers, uplift is more likely to appear, especially for foundations supported by stiff soil, causing significant decrease in moments and deflections.