Portsmouth Memorial Bridge Replacement


Between Portsmouth, New Hampshire, and Kittery, Maine


Groundbreaking design simplifies fabrication, speeds erection and reunites two communities



•    Modified plate girder bridge delivered in 18 months
•    Innovative concepts speed fabrication, construction
•    Bridge becomes world’s first gussetless truss 

As part of a design-build team, HNTB designed the Portsmouth Memorial Bridge’s rapid replacement over the Piscataqua River between Portsmouth, New Hampshire, and Kittery, Maine. 

Promising to deliver a new bridge in 18 months, HNTB rolled out a series of new concepts. Engineers eliminated gusset plate connections to reduce corrosion. They used double sheer connections to reduce the number of bolts. They spanned the bridge deck system longitudinally between floor beams and standardized  the through-truss span for easier fabrication and construction.

The new lift span was constructed off-site and floated into place. The new vertical-lift bridge echoes the look of its predecessor with three identical through-truss spans, a lift tower on each flanking span, two 11-foot through lanes, two 5-foot shoulders for bicyclists and two 6-foot sidewalks inside the truss planes and pedestrian overlooks.

The bi-state owners and their communities received a stronger, safer bridge in record time.