Seismic assessment of different vertical bracing systems in staging of elevated liquid retaining tank

Abstract

The study of earthquakes indicates that earthquakes have a significant impact on the grid system, as well as significant catastrophic effects on human life, buildings, bridges and other structures. In macro scale water distribution network, water tanks play the key point site component, and it is the most vulnerable element in case of an earthquake. Water tanks play a vital role in our lives as they help to store and supply water for domestic and commercial purposes. They also store water for firefighting, irrigation and other agricultural needs. Based on the previous literatures, papers, articles, and other sources, it can be concluded that during an earthquake generally, a liquid retaining structure, i.e., water tank failure generally occurs due to the inability of the staging system to resist lateral movement. Most post-earthquake failures of elevated tanks are likely to result from dynamic buckling caused by overturning moments of seismically induced fluid inertia and surface sloshing waves. As they are the vital structures of our society, their construction and proper seismic evaluation is crucial. In this paper, the seismic response of liquid retaining tanks for different vertical bracing systems has been compared as per IS1893:2014 part-2 and the response spectrum analysis procedure. In all the models the storage tank's capacity has been taken as 150 cubic meters, keeping all the dimensions the same. The loads are considered as per IS875, IS3370 and other relevant codes. The different models considered in this paper are – water tank without bracing, water tank with diagonal bracing, water tank with cross bracing, water tank with K-type bracing, water tank with chevron bracing and water tank with box bracing. These models have been compared on the basis of different seismic parameters and optimized model is being suggested.