Gambo Bridge Replacement at Naval Support Facility Dahlgren

With a weight restriction of just 10 tons, the Gambo Bridge constrained Naval Support Facility Dahlgren’s daily operations, emergency response, and range activities. Built in 1932, the 500-foot-long bridge had deteriorated into a structurally deficient and functionally outdated structure. The project site presented complex logistical, ecological, and safety challenges, including an environmentally sensitive setting, proximity to archaeological sites, and the presence of unexploded ordnance (UXO). In addition, the bridge supported critical utilities, including secure fiber optic lines, which had to remain operational throughout construction.

As designer of record, GFT led a coordinated, design-build effort that balanced environmental protection, base operations, and accelerated delivery. Working closely with the contractor, the team developed cost-effective construction strategies and conducted constructability and value engineering reviews to address environmental constraints while maintaining critical base operations.

The project required coordination with multiple agencies, including Naval Facilities Engineering Systems Command (NAVFAC), the U.S. Army Corps of Engineers (USACE), the National Oceanic and Atmospheric Administration (NOAA) Fisheries, and the Virginia Marine Resources Commission. This collaborative approach streamlined coordination and minimized disruption. Our innovative design incorporated temporary structural systems to enable sequential demolition and phased construction while preserving stability. To avoid construction conflicts and maintain continuous utility service, the team conducted detailed topographic and bathymetric surveys and applied the American Society of Civil Engineers’ Standard 38-02 (ASCE 38-02) to map subsurface conditions and guide utility coordination accurately. The team relocated utilities using horizontal directional drilling to ensure continuous service.