Roads & Bridges Honors George Street Bridge
September 1, 2010
(Mt. Laurel, N.J.) Roads & Bridges magazine ranked the George Street Bridge over Route 18 and Boyd Park as #6 in its “Top 10 Bridges 2010” awards program. This awards program recognizes the best in bridge construction for 2010. Gannett Fleming, an international planning, design, and construction management firm, served as the lead designer and engineer-of-record on this project. The Top 10 Bridges will be published in the November 2010 issue of Roads & Bridges magazine.
The George Street Bridge is one of several bridges constructed as part of the New Jersey Department of Transportation’s (NJDOT’s) $215 million reconstruction of Route 18 in the city of New Brunswick, N.J. The multi-interchange project improved safety and operations for regional travel and provided much needed multi-modal service improvements and local access to downtown New Brunswick, Rutgers University, the Raritan River waterfront, Boyd Park, and various neighborhoods adjacent to the corridor.
From the onset of the Final Scope Development phase, a Context Sensitive Design (CSD) approach was initiated to define a collaborative design solution that met transportation needs, environmental obligations, and community values. Through a Steering Committee comprised of representatives from NJDOT, Gannett Fleming, and the Federal Highway Administration (FHWA), a community involvement action plan was developed that centered on the formation of a Community Partnering Team (CPT).
The CPT was a unique mechanism that obtained broad-based public participation and provided information to stakeholders and community representatives. Concepts developed through the CPT led to the design and construction of the George Street Bridge. A unique structure, the bridge’s construction broke new ground in the use of precast concrete. The resulting bridge truly complements the historical charm of the city of New Brunswick.
The George Street Bridge is one of the largest structures of its kind in North America. Designed as a precast concrete barrel arch bridge that measures 593 feet in length and 60.7 feet in width, it features eight arch barrels, each with a span of 66 feet and a rise of 20 feet. The arch pieces were constructed using 5,500-pounds-per-square-inch concrete and were cast with crown ends to allow them to mate properly.
The height and weight of the George Street Bridge presented a unique challenge. The arches required approximately 12,330 cubic yards of overfill material. Since the arch structure was to be supported on multi-column piers, the design engineers needed to find a way to reduce the mass of this large structure to reduce the seismic loads imparted to the piers.
Gannett Fleming accomplished this by specifying the use of an engineered flowable fill consisting of a lightweight cellular concrete mix with a density of 30-pounds-per-cubic-foot. This material significantly reduced dead load and seismic forces on the piers when compared to the use of a more traditional soil overfill. The George Street Bridge became the first in the world to combine precast concrete arches with a lightweight cellular concrete overfill. Although a unique application, the use of long-span precast concrete arches with a lightweight cellular concrete overfill represents an engineering innovation that proved economical and exceeded the client’s and community’s expectations.
For more information, please contact Paul D. Nowicki, P.E. at (908) 755-0040 or via e-mail.
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