Chapter 8 - Seismic risk of RC water storage elevated tanks: Case study

Abstract

In the field of civil engineering, concrete water storage tanks are considered as hydraulic structures and take a special place among the constructions. The experience feedback, nearly half a century of management, revealed a wide disparity of behavior of these structures to seismic effect, manifested by several pathologies. In this chapter, the concept of seismic vulnerability is used to predict the average level of damage that can occur on an elevated tank under the earthquakes action. We propose a simple and practical method allowing for a civil engineer a quick assessment of the seismic vulnerability of a storage elevated tank. In this method, the level of vulnerability involves 12 parameters. Some parameters characterize the geometry of the tank, while others are associated with the supporting structure as defined by the design engineer and then the rest of the parameters are related to the location of the elevated tank. The vulnerability scale is adapted from the Italian method called Gruppo Nazionale per le Difesadai Terremoti. From a calculated vulnerability index, we propose a tank classification scale in three levels of behavior, which are associated with different colors. The first level includes tanks with good behavior (green); the second includes tanks with an average behavior (orange 1 and orange 2), and the third concerns the tanks with bad behavior (red).