It took only 20 hours this past weekend for crews to demolish and replace the eastbound lane of a twin bridge in Southeast, N.Y., under a federally funded accelerated bridge construction (ABC) program that involves the use of precast parts. The new 80-ft-long and 57-ft-wide bridge with full shoulders sits beside a new westbound span on Interstate 84 over Dingle Ridge Rd. The westbound bridge was completed Sept. 21, also in 20 hours.

Photo by Rick Raglow, Courtesy HNTB Corp.

Smooth Sliding: Working through the rain, crews began demolition of the existing structure at 5 p.m. Oct. 19 and slid the new one into place by 1 a.m. Oct. 20.

The $10.2-million I-84 project is only the second using the Transportation Research Board's (TRB) Strategic Highway Research Program's ABC toolkit, says Bala Sivakumar, vice president and director of special bridge projects at HNTB Corp., project designer and developer of the toolkit. The first was the Keg Creek Bridge in Iowa, completed in 2011.

Working through the rain, crews led by Yonkers Contracting Co. began demolition of the existing structure at 5 p.m. Oct. 19 and slid the new one into place by 1 a.m. Oct. 20, Sivakumar says.

"That seven hours is pretty near record time for this kind of work," he says. The first slide in September took about six hours longer than this one, due to "a slight racking of the bridge" during the slide, he adds. However, "this one was a smooth, even slide."

The project includes new abutments and the roadway was raised about 2 ft to meet the new bridge. After the slide, crews worked till around 12:30 p.m. on Oct. 20 to raise the approaches using large quantities of asphalt applied in layers, Sivakumar says. "There were no significant [traffic] delays," he adds.

While the slides took only two weekends, the entire project including roadwork began last February and is set for completion in December.