Seismic Performance of RCC Elevated Liquid Storage Tank

Rahul Paikrao

Abstract

As compared to other Civil Engineering structures elevated liquid storage tank is the 2nd most vulnerable structure under earthquake excitation, reason is more the flexibility and more the mass causes the longer time periods. In most of the cases it is almost equal to or up to 4 seconds. This paper compares the seismic analysis of Intz, Circular and Rectangular shape elevated liquid storage tanks of capacity 250m3 in accordance with IS: 1893- (Part-2) 2014. To study the effect of shape on seismic performance of elevated liquid storage tank (assumed liquid as water). The analysis is carried out for elevated liquid storage tanks of shape Circular, Intz and Rectangular in seismic Zone-IV and Zone-V and on three different soil types i.e (hard rock, medium soil, soft soil) with two different tank-fill conditions - tank full and tank empty. Further, three different staging heights are also considered in this study. A Programme is formulated in Microsoft Excel software package using IS: 1893- (Part-2) 2014 and GSDMA (Gujarat State Disaster Management Authority) guidelines given by IIT Kanpur. The parameters of comparison include natural time period, lateral stiffness, base shear, base moment at the base of staging, vertical ground acceleration, hydrodynamic pressure, sloshing wave height. The present study will be helpful to Civil Engineers to understand the effect of container shape on seismic performance of elevated liquid storage tanks.