| Résumé : |
They say there is more than one way to skin a cat. That same analogy holds true when considering the maintenance of a water tower. There are numerous approaches including direct selection, traditional design-bid-build, and design-build. Each approach holds merit, and before making the selection, an owner should carefully weigh the advantages and disadvantages of each. Some of these advantages and disadvantages are discussed in a previous article, "Old Tanks, Small Towns, Tight Budgets" (JPCL, May 2005).
The sole purpose of selecting from any of the above approaches is simple: to maximize the service life of the water tower's applied coating system. Selecting an approach may be easier when the scope of work is based on the complete reconditioning or restoration of the facility. The contractor begins with a clean slate, and it is easy to identify where the responsibility lies should there be a premature failure. However, often times this approach is just not possible, and what may be referred to as aggressive maintenance is warranted at the system's approximate half-life.
In 2006, SEH embarked on the design-build method of delivery for water storage tanks, and partnered with a Midwestern contractor. One of the first projects in the program was a 300,000-gallon water spheroid in the City of Eagle River, Wisconsin (referred to from this point forward as "the City.") The tank was last painted in 1991, making the existing coating system 15 years old. The first step prior to developing the project proposal, was conducting a com-prehensive inspection of tank surfaces in accordance with AWWA D101, including interior immersion, interior dry (access tube, riser, and base), and accessible exterior areas. Tank appurtenances were also evaluated for compliance with current AWWA and OSHA requirements.
This article will review the design-build approach to developing and executing a maintenance plan to maximize the tank's coating system service life even beyond the recommended 15 to 20 years. |
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Maximizing water tank service life using a design-build approach in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 31, N° 5 (05/2014)
