North Hero – Grand Isle Drawbridge Replacement, North Hero to Grand Isle, VT
In 1886, engineers built a swing bridge between the Vermont towns of North Hero and Grand Isle. Cranked by hand, this was one of seven movable bridges connecting the Lake Champlain islands. The swing bridge was replaced in 1953 with a twin-leaf bascule drawbridge. Over time, all but one swing bridge was replaced, leaving the North Hero – Grand Isle drawbridge as the only automobile drawbridge in Vermont.
Carrying U.S. Route 2, the bridge is the only connection between the islands and provides a critical link south to the Vermont mainland. It carries 3,000 vehicles daily during the off-season and twice that during the summer and fall. In 2014, a scoping inspection revealed numerous concerns and deficiencies in the bridge. Its open steel grid deck developed numerous holes and pits, exacerbating corrosion and debris on the substructure. The steel girders had deep pitting and rust, the floor beams showed excessive section loss, and the paint system was failing. Moreover, it’s mechanical and electrical systems neared the end of their useful life and failed to comply with modern codes. In fact, it was so worn out that the Vermont Agency of Transportation (VTrans) received permission from the U.S. Coast Guard to open the bridge once an hour instead of twice to reduce wear and tear.
The $74 million North Hero – Grand Isle Bridge Replacement project restores the grandeur of this critical bridge. It maintains the unique design, modernizes the equipment and operations, brings the bridge into code compliance, improves safety, and reduces maintenance. The project team circumvented incredible challenges, including changing a phased construction strategy that would have utilized the existing bridge to using a temporary bridge, maintaining access to both vehicular and boat traffic, unexpected soil contamination, a global pandemic, and sub-zero temperatures. Spanning 160 feet, with two 50-foot approach spans and two 40-foot leaves, the new bridge will serve as the main road through the islands in excess of the next 100 years.