This article discusses the functional requirements, planning, design considerations, and erection aspects involved in the construction of two 10 million gallon (37.9 million liter) precast, prestressed concrete water tanks in Spokane, Washington. The tanks were designed to replace a two-basin, 5-acre open-type reservoir. A major feature of the structures is the combination of single pie-shaped tees for the roof and single tees with exposed aggregate flanges for the circumferential wall. A synthetic liner is used on the interior of the tank to ensure the structure is watertight. The authors describe the design and construction process from the perspectives of the project engineer, the owner, and the precast concrete manufacturer.
