Effect of foundation embedment on seismic behavior of elevated tanks considering fluid-structure-soil interaction

Dynamic behavior of R/C elevated tanks with soil–structure interaction

An efficient methodology is presented to evaluate the seismic behavior of a Fluid-Elevated Tank-Foundation/Soil system taking the embedment effects into accounts. The frequency-dependent cone model is used for considering the elevated tank-foundation/soil interaction and the equivalent spring-mass model given in the Eurocode-8 is used for fluid-elevated tank interaction. Both models are combined to obtain the seismic response of the systems considering the sloshing effects of the fluid and frequency-dependent properties of soil. The analysis is carried out in the frequency domain with a modal analysis procedure. The presented methodology with less computational efforts takes account of; the soil and fluid interactions, the material and radiation damping effects of the elastic half-space, and the embedment effects. Some conclusions may be summarized as follows; the sloshing response is not practically affected by the change of properties in stiff soil such as S1 and S2 and embedment but affected in soft soil. On the other hand, these responses are not affected by embedment in stiff soils but affected in soft soils.

Seismic evaluation of fluid-elevated tank-foundation/soil systems in frequency domain

Evaluation of response modification factor (R) of elevated concrete tanks

This research experimentally addresses the seismic response of a cylindrical liquid storage tank in terms of six factors, i.e., acceleration, displacement, hoop and axial stresses in the tank wall, sloshing and uplift. Both material and geometrical nonlinear interaction due to sloshing and uplift are considered. The simultaneous effects of the fixity condition, the supporting base flexibility and the aspect ratio on the response are presented in radar plots. The results reveal that, depending on the aspect ratio, the supporting base flexibility governs the overall response by activating uplift. A nonlinear elastic spring–mass model gives a good representation of the results.

Mohamed K. Temraz

Papers

Effects of soil-structure interaction on seismic response of elevated tanks