Longfellow Bridge

The Longfellow Bridge carries Route 3 and the MBTA Red Line over the Charles River on eleven open-spandrel steel arch spans between Beacon Hill and Cambridge, opened in 1906 and framed by its four granite 'salt-and-pepper' towers. MassDOT's rehabilitation rebuilt every arch span, retrofitted the masonry piers and dismantled and rebuilt the towers while Red Line service continued, and won the 2019 APWA Public Works Project of the Year for historic restoration. Atlantic Bridge & Engineering worked on the bridge across five contracts from 2010 to 2018.

In Phase I, for SPS New England, ABE furnished and installed the structural steel and cross-bracing repairs, 44 new diaphragms and the utility support structures at piers 1 through 10, after removing the old post bracing and arch-rib diaphragms. For the Phase II design-build joint venture of White-Skanska-Consigli, ABE fabricated the W36 gantry support beams and the temporary support steel that let the arch spans be rebuilt in stages under live traffic, 220 support assemblies, 440 friction connection plates, gantry supports and columns, a grillage pad at span 12 and later shoofly repairs, and then installed the gantry supports and rails. Rebuilding riveted spans also meant working with rivets again: ABE developed a method in its own shop for replacing more than 50,000 worn rivets safely and cost-effectively.