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Earth Anchoring Suppliers (EAS) gave material and logistical support to a collaborative effort of Connecticut-based Conte Company, LLC (Conte) and GZA GeoEnvironmental, Inc. (GZA) for a design-build trail system in northern New England. The trail is over 8 miles long with 12 bridges and 21 boardwalks over streams, rivers and wetlands. The bridges ranged from 25-70 feet long and up to 5.5 feet high. The boardwalks ranged from 12-175 feet long and were up to 7.5 feet above wetlands.
Due to the stickup of the piles above the ground (up to 7.5 feet) and corrosion potential, GZA and Conte asked EAS to supply CHANCE round shaft RS3500 and RS4500 piles for the water crossings. In general, RS3500 piles were used for stickups less than 1.5 feet and RS4500 piles for greater than 1.5 feet. For unbraced lengths between 5-6 feet, an additional pile was added to each bent. For larger unbraced lengths, battered SS175 piles were added to resist the lateral loads.
The superstructure of the bridges consisted of W-beams connected directly to the helical piles to form a bent. Each of the bents were connected to one another with longitudinal W-sections with C-channel cross frames. A galvanized steel framed decking system with IPE decking was installed over the longitudinal W-sections. GZA and Conte designed the connections between the helical piles and W cross beams. For standard connections with no battered piles, the connections consisted of 6-inch wide and 12-inch long plates with a pipe fitting that could be bolted to the top of the helical piles.
The boardwalk superstructures consisted of C-channels connected directly to the helical piles. The galvanized steel framed decking system was installed directly over the C-channel cross beams. The helical piles were connected to the C-channels with a similar plate as the bridge connections.
Production piles for the bridges and boardwalks took approximately 5 weeks to complete during the winter of 2017 and the summer of 2018. Conte converted a Polaris UTV into a tool and material carrier to travel the 60+ miles in and out of the woods each day with the workers. An ATV and small trailer were also used to carry tools, generators, and the required material accessories through the 40,000 plus feet of narrow forested trails. Some of the wetlands crossings were within a few hundred feet of one another, but others were several miles apart. With only four entrances into the trail from the logging access road, crews were forced to track the excavator through the wooded trail, sometimes for hours to reach the next crossing. All materials were brought by a skid steer with forks to each crossing. The EAS team was instrumental in keeping the steady flow of helical piles to the remote location.
No disturbance was allowed in the wetlands, streams and rivers. Helical piles were the only part of construction allowed to take place within these protected areas. Since the boardwalks and bridges were designed to meet the construction loading and the final use loading, the site contractor could move their small equipment over each crossing to continue work activities on the trail system.
Helical piles were the best option on this site for many reasons including:
- The segmented pieces allowed for easy travel on the long, narrow, wooded trails;
- The small installation equipment could traverse the narrow trails and still reach off the crane mat staging to perform the work; and
- The minimal disturbance during pile installation allowed for work to be performed within a natural wetlands area.
With the ability to adjust the design and pile locations on the fly due to obstructions or change of conditions, the Owner was able to receive the final product that they requested, even with differing and unforeseen conditions. Very few pile support systems can check all those boxes. At the end of the day, the boardwalks and bridges were constructed ahead of schedule, within budget, and to the satisfaction of the Owner: it was a highly successful collaboration for all.
Earth Anchoring Suppliers Supports Conte Company and GZA in the Creation of a Majestic, Low Impact Walkway in the Wilds of Northern New England
by Keith Dolan