Assessment of International Seismic Design Codes for Partially Filled Elevated Water Tanks Using Experimental and Numerical Investigations

Abstract

Elevated water tanks (EWTs) are one of the most important structures, particularly in highly seismic regions, due to their role in supplying water and extinguishing fires during and after an earthquake. Therefore, they should be designed to withstand the expected seismic loads. This paper aims to evaluate current Response Spectrum Analysis used in Eurocode 8, ACI 350.3-06, and ASCE 7-16 for EWTs. These codes are based on the simplified theory expressed by the method of mass-spring equivalent system. In this study, finite element models of the EWT based on different soil types, medium and hard soil at various levels of tank fullness, are analyzed using ANSYS Software, considering the water sloshing effect to evaluate the code provisions of EWTs, A comprehensive time history analysis is performed under seismic loading. To provide a more accurate assessment of the EWT frequencies, a laboratory experiment using Digital Image Correlation (DIC) was conducted. The maximum shear force and bending moment at the tank's base are analyzed under several scenarios. The results indicated that current international may not provide precise seismic response predictions for EWTs, especially under variable fill conditions, and that the sloshing phenomenon on the water's free surface is a crucial component of tank study and design.