Jan 22, 2010

Building Sustainable Infrastructure

Related Searches from WaterInfoLink.com Prestressed Concrete Tank | CH2M HILL | DYK, Inc.

DYK, Inc. , an award-winning leader in the prestressed concrete tank industry, is currently working on several projects in New York as the general contractor, tank contractor and prestressor. These projects include a 30-million-gal tank for the Onondaga Country Water Authority in Manlius, just east of Syracuse, as well as a recently completed 350,000-gal "tilt-up" tank for the Village of Adams.

Additionally, working with consulting engineers CH2M HILL and O'Brien & Gere, the City of Syracuse is currently renovating its Westcott Reservoir by constructing twin 32-million-gal concrete water storage tanks. The project allows the disused open basin to be brought back online, meeting current drinking water standards for quality, while adding 64 million gal of secure storage to the city’s drinking water system. At 375 ft in diameter and 43 ft tall, these tanks are the largest prestressed concrete tanks east of the Rocky Mountains, and the fourth largest in the world.

Constructed in 1930, the city’s 110-million-gal Westcott Reservoir faithfully provided storage for the city’s drinking water supply for nearly 70 years. However, water quality issues with the uncovered reservoir along with a failing liner and piping prompted the city to close the reservoir in 1999. An engineering evaluation concluded that repair would not be the most cost-effective solution. Concrete storage tanks were selected, as they would provide the desired water quality, security needs and meet current regulatory standards. Prestressed concrete tanks reduce maintenance and are designed with a lifespan to provide the city with clean drinking water into the next century.

Funding for the $40-million project was a significant concern. However, the city was able to obtain a federal matching funds grant through the U.S. Environmental Protection Agency, as well as a subsidized loan through the New York State Environmental Facilities Corp. In addition, the city plans to install solar panels on top of the South Tank that will provide virtually all of the power needed to operate the site.

The two covered tanks are being built concurrently within the existing Westcott Reservoir's earthen footprint. The prestressed concrete tanks have cast-in-place corewalls, and will be bi-directionally post tensioned, providing enhanced durability to the concrete structures. In addition, the circumferential wrapping of the tank will incorporate galvanized prestressing, a new feature for the area but already commonly used in the Western U.S. Galvanizing offers a further layer of environmental protection to the core of the tank structure, and provides further confidence in its longevity.

Construction of the tanks began during fall 2008. In order to keep the project on schedule, construction progressed through the winter. Despite considerable snowfall and cold temperatures, significant progress was made during the winter months, but it required soil to be thawed prior to construction and concrete to be heated for several days after pours to ensure proper curing. The first tank was completed in December 2009, and completion of the second tank will follow shortly thereafter in mid-2010.

This project reflects the efficient use of available space while guaranteeing minimal disturbance to the surrounding community, which was important to the city. Since the tanks are located inside the existing reservoir basin, and the site entrance is obscured by a new earthen berm and curved access road, most nearby residents will not be able to see the tanks. Upon completion, the tanks will bring the city’s drinking water system into compliance with new regulations, while also enhancing water quality and improving security due to the protection offered by closed storage tanks. Most notably, the tanks will provide more than 200,000 residents in the city of Syracuse with safe and reliable drinking water for generations to come.
Photos by Photography Reece, Syracuse, N.Y.