Commodore Isaac Hull Bridge Emergency Rehabilitation

The Commodore Isaac Hull Bridge carries Route 8 over the Housatonic River between Derby and Shelton. When inspections identified deterioration in steel gusset plates essential to the bridge's truss system, the Connecticut Department of Transportation (CTDOT) initiated an emergency rehabilitation program to restore structural integrity and maintain the reliability of this vital corridor.

CHA served as the lead designer, performing an expedited structural assessment that identified additional concerns and informed CTDOT's emergency declaration. Working under aggressive schedule constraints, the team evaluated both conventional steel repairs and innovative alternatives before developing a first-of-its-kind rehabilitation strategy using ultra-high-performance concrete (UHPC). Leveraging UHPC's exceptional strength, durability, and flowable properties, the design created a secondary load path that restored capacity to critical gusset plates while overcoming the constructability challenges associated with working in confined spaces within the bridge's truss system.

The project repaired 12 gusset plates across three truss spans and incorporated a polymer pavement-coating overlay to reduce dead load on the structure and improve long-term performance. Completed in less than four months, the rehabilitation restored structural reliability with minimal disruption to the traveling public.