Historic Rockville Bridge Rehabilitation

Located just south of State Route 9 within the Town of Rockville, Utah, the Historic Rockville Bridge carries the single‐lane Bridge Road across the Virgin River and provides the only access to several residences and ranches south of the river.

The 217‐foot, rigid‐connected bridge consists of 12 panels in a single‐span steel truss supported by concrete abutments. Constructed in 1924, the Rockville Bridge is the only remaining Parker Through Truss bridge in Utah still open to traffic. In 2012, a Utah Department of Transportation (UDOT) inspection of the bridge revealed significant deterioration. The bridge’s load rating was downgraded to 14 tons and then further downgraded to six tons, too low for emergency and trash removal vehicles. As a result, plans were made for a new two‐lane replacement bridge. However, local residents and property owners overwhelmingly preferred restoration of the existing bridge, which shifted the project scope. With the rehabilitation approved, UDOT hired Lochner to provide design and construction management.

Through structural design and rehabilitation efforts, Lochner improved the bridge’s load rating to 25 tons. The project required extensive coordination with the Town of Rockville as well as the State Historic Preservation Office (SHPO). Lochner’s relationship with SHPO ensured improvements maintained the existing Parker Through Truss’ historic significance and preserved the bridge’s place on the National Historic Register. To increase capacity sufficiently, a timber glulam deck was used and four of the diagonals were replaced in kind. Additionally, steel stringers were swapped out and the floor beams were strengthened. In this manner, the historic appearance was not only maintained, but enhanced while upgrading the structure to meet the current needs of the citizens.

Additionally, Lochner provided utility coordination; design of a temporary one‐way, bypass road consisting of dirt fill over six large culverts for traffic use during construction; environmental clearance for both the bypass road and the bridge historical preservation efforts; river hydraulics; and project management.