In September 2011, the bridge on Duanesburg-Churches Road in east-central New York near Albany, was completely washed out during Hurricane Irene. The bridge was closed for a year and a replacement was needed that could handle the velocities associated with a 100-year storm. Schenectady County selected engineering firm Greenman Pedersen to design the replacement.
Based on successful past project collaboration, Greenman Pedersen again consulted with Contech Engineered Solution. They determined a three-sided structure was the best solution, and chose a 28’ x 10’-3.5” x 52’ CON/SPAN® O-Series™ bridge system. The O-Series three-sided precast structure offered a number of advantages over other solutions, including a more efficient structure, cost competitiveness, high-quality precast concrete, an attractive appearance and arch strength.
“When Contech showed us the new shape they were proposing, we were very interested,” said Michael Borgel, P.E., of Greenman Pedersen. “The owner asked us for our thoughts and we recommended the new CON/SPAN O-Series shape to them based on our past experience with using the basic CON/SPAN shape.”
For this bridge structure, riprap was used as a scour counter measure. In order to place the riprap prior to the installation of the bridge units, 6-foot tall cast-in-place pedestal walls were utilized.
Seven precast concrete CON/SPAN® O-Series arch units were installed along with detached counterfort headwalls which all met New York State Department of Transportation (NYSDOT) specifications.
The use of precast bridge components provided the County with an efficiently-constructed bridge, designed in accordance with NYSDOT item #562.01, that saved money and time — especially since the order to installation time was just three months! The bridge structure itself, including the arches and headwalls, was installed in just one day. In addition, the structure will last and perform well for many years to come.
With a history of innovation and experience, Contech has taken precast buried bridge systems to the next level with the introduction of the optimized O-Series in 2012. Requiring less concrete per open area than any other precast buried bridge structure, the O-Series is the ideal blend of hydraulic efficiency and structural capacity. Spans range from 12 to 65 feet.
The Duanesburg-Churches Road replacement structure was completed on time and within budget. “The project came together very nicely, and the owner is very pleased with the finished project,” added Borgel.