FAILURE CRITERIA AND ANALYSIS OF AN UNDER GROUND RESERVOIR ON SUBMERGED SOIL USING PRINCIPLE OF BUOYANCY

Abstract

The basic requirement in the design of reinforced water tank is to ensure it must be crack free. This study is about the analysis of an underground reinforced concrete water reservoir under fully submerged soil prone to exert buoyant force. A Microsoft Excel Spreadsheet is generated for quick assessment of behavior in various conditions of reservoir, geometrical features, critical condition for upliftment for both full and empty conditions of the tank and the probable feasible solution. It has been observed that the empty tank on fully submerged soil becomes the most critical condition in terms of factor of safety and to sustain in this condition geometrical modification is not sufficient and also uneconomical. In all the examined probable solutions, the base extension with considering the weight of soil wedge due to angle of internal friction of soil and provision of anti floatation slab gives satisfactory stability to the water reservoir on fully submerged soil. Considering both the above mentioned solution, a comparison study is made on STAAD Pro for determination of node displacement, shear stresses & moment at base slab and side walls.