Seismic Response of Cylindrical Tanks with Dual Concrete and Elastic Baffle System

This paper concerns the seismic response of cylindrical concrete tanks accommodated simultaneously with concrete and elastic membrane baffles. The idea originates from the fact that in order to contain the seismic sloshing, a large area of the free surface of the liquid has to be covered. While this is not possible with concrete baffles, elastic membranes are ideal choices for the same purpose. Three concrete tanks having height-to-diameter ratios corresponding to shallow, intermediate, and tall tanks, are selected for this study. They are provided with concrete and elastic baffles being different in the relative area covered by the elastic baffle. Maximum responses including the seismic sloshing height along with the base shear and overturning moment are calculated under bi-directional horizontal components of 11 consistent earthquake ground motions. The average of the maximum responses under the earthquakes is calculated. It is shown that the use of elastic baffles covering 0.4–0.6 of the tank radius results in a 30–60% reduction in the sloshing height. This is while the overturning moment and base shear increase slightly, up to 20% in the worst case and only 9% on the average. Then, the use of an elastic membrane is recommended as a viable solution to reduce seismic sloshing in cylindrical tanks.