Jeffery Benway P.E., in collaboration with S.W. Cole Engineering, designed the first ever GSR retaining wall in a marine environment in association with Redi-Rock of Central Maine. He was thrilled to be part of such a unique project.
Two years ago, the town of North Haven, Maine, began construction on a very unique bridge project. Their goal was to re-build a currently deteriorating bridge, which provided access to several homes, and was an essential wharf for the towns local lobster industry.
North Haven is an island, off of the coast of Maine, all materials needed to be brought over via boat. The daily tidal variations affected construction, and the wall needed to be able to handle the impact of boats navigating the waterway. “This area doesn’t get wave action, but there’s a very large tidal change – around 6 to 8 feet (1.82 to 2.44 meters). They wanted to use a larger block system that could withstand the tidal changes as well as potential impact from boats” explained Benway, P.E. of SFC Engineering. “The Town found the best solution to these issues was to construct a Geosynthetic Reinforced Soil – Integrated Bridge System (GRS-IBS)” said Benway. He facilitated in the decision to use a GRS wall as opposed to a traditional wall. He explained, “The main difference between a GRS wall and a traditional mechanically stabilized earth abutment wall is that reinforcing fabric is used in much more closely spaced layers, and the fabric is not geogrid. What’s typically used is more like a filter fabric. It doesn’t have the same strength as geogrid, but it’s much more closely spaced – every 6 to 9 inches (150 to 230 millimeters) versus every 18 inches (457 millimeters) with a traditional Redi-Rock wall. This allows the fabric to act as a tension element in the soil. The facing unit isn’t really retaining the soil at all; it’s simply preventing erosion of the reinforced soil mass.”
Despite the many challenges; the project was a success. The wall was completed in April of 2014 and took roughly 4 months. Jeff Benway was featured in Roads and Bridges Magazine, as well as, Redi-Rock International’s official website. Congratulations Jeff!
Publications:
http://www.roadsbridges.com/maine-bridge-uses-first-grs-wall-marine-environment
http://www.redi-rock.com/unique-bridge-repair-using-GRS-wall-solution.htm
