Bridge Facts

  • History
    • Built in 1940, The Sarah Mildred Long Bridge provides a regional link between Maine and New Hampshire and is the critical back-up route in case of disruption on the Interstate 95 Bridge.
    • The bridge was the direct result of the work of the Maine-New Hampshire Interstate Bridge Authority, which had been formed in 1937.
    • For many years, the bridge was known as the Maine-New Hampshire Bridge. In 1987, the bridge was renamed to honor Sarah M. Long, an employee of the Maine-New Hampshire Interstate Bridge Authority for 50 years.
  • Replacement Project
    • Joint venture between the Maine and New Hampshire Departments of Transportation, with MaineDOT serving as the lead.
    • Project is part of a “Three Bridge Agreement” between Maine and New Hampshire to address their jointly owned bridges spanning the Piscataqua River.
      • Other two bridges are the “high level” bridge that carries I-95, and the Memorial Bridge that links the communities of Portsmouth and Kittery.
    • Project is expected to cost approximately $158.5 million.  In September 2014, a $25 million TIGER (Transportation Investment Generating Economic Recovery) Grant was awarded for the rail portion of the bridge. 
    • The new bridge was designed by a joint venture between specialty bridge design firms FIGG I Hardesty & Hanover. Maine-based Cianbro will be the construction firm for the project.
    • Design process began in 2013 with construction starting winter 2015.
    • Traffic will be impacted for around 10 months at the end of the project as it intercepts the old bridge at the Kittery side
      • Traffic will be detoured to the Piscataqua River Bridge on I-95.
    • New bridge is scheduled to open in late September/early October, 2017. 
  • Key Bridge Attributes
    • New bridge alignment improves marine navigation by straightening the navigational channel, allowing larger ships to access the port and shipyard.
    • With a larger 56’ vertical clearance in its “resting” position, there will be 68% fewer bridge openings. In the normal operating, “resting” position, the bridge’s lift span is at its middle level, allowing motor vehicles to cross the river. The new bridge’s movable “hybrid” span lifts up to allow passage of tall vessels and lowers to railroad track level for trains to cross.
    • 200’ tall precast concrete towers will support the 300’ long streamlined structural steel box girder lift span.
    • New bridge layout uses eleven (11) fewer piers than the existing bridge, also improving the gateway span leading into downtown Portsmouth by eliminating an existing median pier. 
  • The 200 ft. tall precast concrete towers will support the 300 ft. long streamlined structural steel box girder lift span.
  • New bridge alignment improves marine navigation by increasing the navigational clearance, allowing larger ships to access the port and shipyard.
  • Each of the four towers of the bridge will have 22 concrete segments and will rise 215 feet above the water. Each tower Each tower segment weighs 80 tons.
  • With a larger 56' vertical clearance in its “resting” position, there will be 68% fewer bridge openings.
  • This significant undertaking is expected to cost approximately $158.5 million.
  • The new lift span currently weighs approximately 3 million pounds in its “float-in” configuration. Once complete and placed in-service the new lift span will weight approximately 4 million pounds or 2000 tons.
  • There are eight operating ropes (steel cables) that pull the counterweights up and down to lift and lower the bridge. If laid end to end these operating ropes would stretch over a mile. The forty counterweight ropes that support the four corners of the new lifts span would extend over 2 miles, if they were laid end to end.
  • There are four counterweight sheaves (one per tower) which transfer the load of the bridge and counterweights to the tower. Each sheave measures 20 feet in diameter and they weigh 100 tons a piece.
  • Too put these weights in perspective a standard pickup truck weighs approximately 2 tons.