I-84 over Dingle Ridge Road - Rapid Bridge Replacement, Brewster, N.Y.

Photo Courtesy of Andy Ryan Photography/HNTB Corp.

This $10.2-billion accelerated bridge construction (ABC) project involved demolishing and replacing twin steel-and-concrete spans with two prefabricated bridge elements assembled alongside the existing structures. Part of the ongoing federal Strategic Highway Research Program to quickly repair aging infrastructure with minimum disruption to users, this project was chosen to demonstrate ABC methods for replacing spans via the lateral slide method while using a concrete superstructure.

To replace the 50-year-old bridges, the team built foundations for the new structures and used precast concrete bridge beams that were made off site and shipped to the Dingle Road location. The superstructures were assembled just north of each existing span.

During two weekend-long bridge closures, the older spans were demolished and the new ones slid sideways into place and secured. The entire project including approaches and roadwork lasted only 10 months.

Each new structure is 57 ft wide to accommodate three 12-ft traffic lanes, with a 6-ft left shoulder and a 12-ft right one. Each also has a TL-5 concrete barrier on each side. Each span includes an 80-ft, single-span double-tee beam superstructure. Each has semi-integral abutments with elevated cap beams supported on drilled shaft foundations.

The designer and structural engineer says the ABC method coupled with substantial use of precast elements benefited stakeholders by avoiding costly traffic delays, improving safety, protecting the environment by avoiding cross-overs and eliminating the need for a temporary bridge. The firm adds that this approach ultimately saved the state $2 million and about one year of construction time over the usual bridge replacement approach.

Key Players

Owner/Civil Engineer New York State Dept. of Transportation

General Contractor Yonkers Contracting Co.

Lead Designer/Structural Engineer HNTB New York Engineering and Architecture PC

Precast Concrete Engineer/Fabricator Dailey Precast LLC

Contractor's Erection Engineer Siefert Associates LLC

Heavy Lift Contractor Marino Crane

Construction Inspection Parsons Brinckerhoff