"Design-build was the only way we were going to make schedule," says Michael J. McBride, MWRA deputy chief operating officer. Norumbega is a critical part of the system because it serves as a day tank for Boston. MWRA is finishing up a $1.7-billion program that includes building a new water supply tunnel, an ozonation treatment plant and six storage tanks to comply with federal safe drinking water standards and to enhance system reliability.

BIGGEST Norumbega tank is largest in U.S. but started late due to land issues. (Photo by William J. Angelo for ENR)

Massachusetts is one of a handful of states that requires special legislation for design-build on public projects. MWRA has completed four tanks using traditional delivery and has one more to go using design-build. The agency has short-listed five firms for the $28-million, 20-million-gallon Blue Hills covered tank. "We're in the middle of the permitting stage and proposal documents and technical requirements will be out this summer," says McBride. RFPs will be evaluated this fall and an award made at year's end. Blue Hills must be completed by December 2006.

The 115-million-gallon cast-in-place concrete Norumbega tank may be the largest in the U.S. The three-cell structure, designed by Metcalf & Eddy, Wakefield, Mass., and Weidlinger Associates, New York City, is 1,300 ft long, 625 ft wide and 28 ft deep. Work began in June 2000. When completed next year, it will replace the nearby 205-million-gallon Norumbega reservoir.

"We're working longer days and Saturdays now for a phased two-cell opening starting in October," says Marco DePalma, superintendent for Norumbega Constructors, a Framingham, Mass-based joint venture of J.F. White/Slattery. The last cell will be ready in September 2004.

To help speed ceiling work, Ceco Concrete Construction LLC, Bloomfield, Conn., is using a rolling scaffold deck system combined with 16-ft-long, 8-ft-wide aluminum mega-beam panels that eliminate shoring between columns. "The system eliminates about one-third of the scaffolding, or about 2,000 frames," says Dean R. Clawson, Ceco superintendent. "We simply block up the system, do the pour, then wheel it to the next pour. We don't have to reassemble scaffolding and that cuts our manpower needs in half."

McBride estimates the agency saved 5 to 7% using design-build. "We anticipate savings in the same range for Blue Hills," he says.