Bridge Over Wallkill River
A new precast concrete replacement bridge over the Wallkill River in Middletown, New York, features a haunched-girder design that allowed the spans to be lengthened, eliminating two sets of piers in the water. The design was created by the New York State Department of Transportation (NYSDOT) and produced by J.P. Carrara & Sons Inc., of Middlebury, Vermont.
The bridge, which replaces a deteriorated four-span steel design, has finished its first phase, in which 10 end segments and five haunched (center) segments were erected. The second phase, which will begin in the spring, will shift traffic to allow construction of the eastern half of the project (12 end segments and six center segments). The third phase, in late summer, will shift traffic back to allow finishing of the final portion (12 end segments and six center segments).
"The structure represents one of the first post-tensioned, haunched NEBT girder designs used in the state", says Joe Carrara, sales manager of J.P. Carrara & Sons Inc. The design proved to be more economical and faster to build than other options. The haunched NEBT girders also offered less environmental impact, as the lengthened spans eliminated piers. The haunched design handles moment over the piers and allows for a continuous, two-span design when post-tensioned.
The design features two end spans of approximately 128 feet and a 105-foot center span. The structure was temporarily shored up during erection, with closure pours created between the spans prior to post-tensioning.