Anchoring of empty underground tanks against underground-water-induced floatation by using arched cable system

摘要

An empty underground storage tank, constructed within the fluctuating rise and fall of underground water level, can move upward by an uplifting pressure equal to the weight of the displaced water minus the self weight of the tank. Several methods are used to hold such tanks in position. Piled foundations are used as one of these solutions, in which the piles are subjected to pulling out forces. Practically this solution has many structural defects in addition to its high cost. In this article, it is proposed that an arched cable system could be used to anchor empty reinforced concrete rectangular tanks against any floatation caused by the uplifting pressure which might be generated by the rise of the underground water level. An arched cable is placed through a parabolic profile duct embedded in the concrete of each of the tank long walls and anchored at its ends. The equations required to design such system are demonstrated by using an illustrative example.