When the City of Alexandria decided their 70+ year old, one million gallon welded steel water tank needed to be repaired and painted, MML&H was selected for the project. MML&H engineer Heath McGuffee (pictured with the tank) inspected the tank and determined that the deterioration of the tank was more severe than originally believed. MML&H prepared a 20-year life-cycle cost analysis to compare various options for repairing and/or replacing the existing tank. Based on the analysis, it was soon realized that it would be more cost effective for the City of Alexandria to demolish the current welded steel tank and rebuild a new prestressed concrete tank in its place.
The prestressed concrete tank was selected over other alternatives because of its relatively long life and fewer maintenance requirements compared to a welded steel tank. Depending on market and site conditions, prestressed concrete tanks are also more cost effective than bolted steel tanks in larger sizes, generally starting at one million gallons. Prestressed concrete is engineered with single-wire prestressing to assure a permanent cylindrical compression in the tank wall, therefore the walls and floors are not required to be as thick as traditional concrete tanks. The majority of the floor for this one million-gallon tank is only 4 inches thick. The new tank was built by Precon Corporation on the same footprint as the previous tank. Although prestressed concrete tanks do not require coating, the City of Alexandria opted to paint their new tank with their City logo for aesthetics. Meyer, Meyer, LaCroix & Hixson, Inc. (MML&H) has also designed prestressed concrete tanks for other clients including the City of Winnsboro, the Town of Delhi, the Buckeye Water District, and the City of Oakdale.
