I-95 Piscataqua River Bridge Rehabilitation, Portsmouth, NH
The I-95 Piscataqua River Bridge carries six lanes of Interstate 95 between Portsmouth, NH, and Kittery, ME. The 4,503-foot-long through-arch structure is vital to freight traffic, commuters, and tourists. An average of 78,000 vehicles crosses the bridge each day. In the summer tourist season, daily traffic counts can rise to 130,000 or more, leading to regular traffic jams. As part of the first major rehabilitation since the bridge’s construction in 1972, TYLin was tasked with improving the safety of the bridge, developing rehabilitation designs, and identifying a way to move more traffic through the corridor using the existing structure. TYLin proposed an intelligent transportation system (ITS) to dynamically use emergency shoulders as a fourth traffic lane in each direction when needed during peak traffic periods – a move that will greatly improve traffic flow. The bridge rehabilitation project has prepared the structure and its approaches for the ITS, which is expected to be installed by the New Hampshire Department of Transportation by the end of 2023.
The greatest challenge of the $56.3 million bridge rehabilitation was keeping traffic and commerce moving freely every day of construction. Working closely with the owners, TYLin developed an innovative traffic control approach. TYLin evaluated the traffic levels at the site for every hour of every day of the year. The team created an intricate, incentivized traffic control plan identifying when and where the contractor could perform the rehabilitation work with minimal traffic disruption. The project utilized a movable temporary concrete barrier system that allowed lanes to be opened and closed quickly, multiple times each day. This rapid deployment maximized the contractor’s time to work, shifting the focus as traffic dictated to keep cars and trucks moving while ensuring the safety of construction workers and the public. This novel approach has only been used a few times nationally, and it had never been utilized on a project in New Hampshire or Maine. The creative solution worked exceptionally well, allowing this massive project to be completed with minimal impact to the public and no claims from the contractor. The project was completed ahead of schedule – a win for travelers and the bridge owners. This iconic structure now meets current safety standards and is set to serve for many more years. With the improvements, travelers can feel safe and confident as they cross high above the Piscataqua River.