The Massachusetts Department of Transportation (MassDOT) selected STV as lead designer for the replacement of the aging Belden G. Bly Drawbridge on Route 107, a key connector between Lynn and Saugus that opens approximately 2,500 times per year to support marine traffic. The goal was to deliver a modern movable-span that maintains reliable vehicle and maritime access while enhancing safety, mobility and community connectivity.
What challenges did STV address?
The project introduced numerous technical and geometric constraints: a low roadway elevation prevented deep pit foundations, marine clearance was limited, right-of-way was restricted and the community context necessitated bike lanes, sidewalks and traffic improvements. STV addressed these by selecting an innovative heel-trunnion bascule design with overhead counterweight and carefully balancing span mechanics, crane/gear tolerances and utility relocations – all while minimizing disruption to adjacent neighborhoods and waterway traffic.
What solutions did STV deliver?
STV’s interdisciplinary team developed the structural, mechanical and electrical design for the new single-leaf bascule span, including a segmental gear drive system, overhead counterweight tower and reconfigured approach roadways with complete streets amenities. The design accommodates bicyclists and pedestrians, provides effective traffic flow and supports marine navigation. Geotechnical and foundation designs replaced timber piles with driven-pile abutments and integral piers. STV also coordinated utility relocation (including a major water main).
How does this project benefit the community and region?
By replacing an outdated drawbridge that caused recurring delays and navigation issues, the new Belden G. Bly Bridge enhances traffic reliability for motorists, improves connectivity for cyclists and pedestrians and facilitates uninterrupted marine access for local fisheries and recreation. The project strengthens regional mobility, helps revitalize the Lynn-Saugus corridor and exemplifies how infrastructure renewal can support safe, modern, multimodal travel.
Key Stats and Accolades
- The new bridge uses an overhead counterweight, heel-trunnion bascule design to meet low-clearance constraints.
- Approaches include new sidewalks and bike lanes, aligning with Massachusetts’s Complete-Streets policy.
- Design aimed to minimize right-of-way impacts and maintain marine and vehicular operations during construction.
