Memorial Bridge 1923-2012

Constructed between 1920 and 1923 and demolished in 2012, Memorial Bridge was the second bridge built across the fast and deep waters of Portsmouth Harbor and the first vertical lift bridge constructed in the eastern United States. When completed, it had the longest lift span and highest lift towers in the nation, became the prototype for many later and larger lift bridges, and inspired the 2013 lift bridge. Funded equally by the United States, Maine, and New Hampshire, it culminated a long campaign to replace a dilapidated 1822 toll bridge upstream with a less expensive movable bridge design that could still accommodate large ships passing farther up the river. The new free bridge gave New Hampshire workers direct access to the Portsmouth Naval Shipyard in Kittery, Maine, and it was dedicated on August 17, 1923, as a memorial to those who served in World War I. Its opening brought the newly created U.S. route and interstate traffic through the center of Portsmouth, making it a vital Eastern Seaboard transportation link and helping prompt the need for additional bridges across Portsmouth Harbor, including another vertical lift bridge on the Route 1 bypass and the high-level Piscataqua River Bridge completed in 1973. Memorial Bridge was designed by J.A.L. Waddell, the prominent bridge designer of the area, who claimed more than 1,000 bridges, developed vertical lift bridges in the United States, and held patents on most aspects of their operation; on the strength of this bridge and two other contemporary bridges, his design was adopted worldwide where spans greater than 300 feet were required. In 1924, bronze plaques and sculptural elements were added to the south portal, including a plaque honoring World War I sailors and soldiers, the United States and New Hampshire seals, and an eagle with outstretched wings, and these were reinstalled on the 2013 bridge. Construction over the extreme tides and currents of the Piscataqua River was especially challenging: Holbrook, Cabot, & Rollins used watertight caissons for deep underwater excavation for the piers, and the American Bridge Company assembled the superstructure spans on the Boston & Maine Railroad’s Market Street Wharf in Portsmouth before floating them in at slack tide on barges built by tugboats. Ninety years later, the trusses for the 2013 bridge were moved into place the same way to rest on the original 1922 piers. To let tall boats pass, the center span rose between flanking towers, with steel pulleys carrying cables that connected the lift span to counterweights balancing its weight, while electric motors raised or lowered the span with a separate set of cables. The 2013 Memorial Bridge, designed by Theodore P. Zoli III of HNTB Corporation and constructed by Stephen A. DelGrosso of Archer Western Contractors, introduced further innovations, including being the first truss bridge built without gusset plates, using identical steel sections spliced together, introducing cold bending of steel to truss bridge construction, using a zinc coating for longer-lasting protection than paint, and rehabilitating the original 1922 granite piers with micropile technology.

Portsmouth, New Hampshire · United States