Abstract: A prestressed concrete tank includes a pair of generally parallel, laterally spaced, straight concrete wall sections which are preshrunk by the application of compressive forces. Straight wall sections are constructed on top of a footing covered with a plurality of plastic sheets to reduce friction so that limited longitudinal movements of at least portions of each wall section are facilitated during the preshrinking operation. The ends of the tank comprise semicircular walls which are prestressed using wire tendons extending peripherally around the wall and tightened to impose centripetal forces on the wall and thereby place the same into circumferential compression. The walls each comprise a substantially vertical steel shell diaphragm with a layer of cementitious material such as shotcrete on each side thereof.

Abstract: A self washing water storage tank has a floor, a cylindrical, generally upright, peripheral concrete wall which sits on the floor and extends around and defines a water storage chamber, and a concrete roof that is mounted atop the wall in substantial covering relationship to the chamber. The roof is essentially flat and has an internal surface which faces the chamber. The tank is arranged such that during the fill cycle the water level rises to a high water level which is above the interior surface of the roof so that such surface is washed during each fill cycle to prevent damage from corrosive gases which may escape from the water and accumulate on the interior surfaces of the tank above the water level.

Abstract: A prestressed concrete tank includes a pair of generally parallel, laterally spaced, straight concrete wall sections which are preshrunk by the application of compressive forces. Straight wall sections are constructed on top of a footing covered with a plurality of plastic sheets to reduce friction so that limited longitudinal movements of at least portions of each wall section are facilitated during the preshrinking operation. The ends of the tank comprise semicircular walls which are prestressed using wire tendons extending peripherally around the wall and tightened to impose centripetal forces on the wall and thereby place the same into circumferential compression. The walls each comprise a substantially vertical steel shell diaphragm with a layer of cementitious material such as shotcrete on each side thereof.