Henry G. Gilmerton Bridge (Military Highway) Replacement
The Gilmerton Bridge Replacement project, located on Military Highway, west of Brainbridge Boulevard, crosses the Southern Branch of the Elizabeth River. This bridge is operated by the City of Chesapeake, but the project was managed by VDOT. Built in 1938, the original bridge was a four-lane double-leaf bascule bridge. The bridge was travelled by more than 35,000 motorists daily.
Built on the same alignment as the existing structure, the $158 million four-lane replacement bridge is a life bridge with 18 approach spans. The bridge has been designed with provisions to expand to six lanes when future widening is required. The structure is 1,908 feet long, 85 feet wide, and has a 250 foot steel truss vertical lift span. Whereas the existing bridge had a vertical clearance of 7 feet above mean high water and 9 feet above mean low water, the replacement structure has a vertical clearance of 35 feet when the bridge is in the closed position and up to 135 feet when the lift span is opened.
The increased clearance will accommodate marine and motorist traffic with fewer bridge openings. It formed an alternative route to the High Rise Bridge and provided direct access to south-eastern Portsmouth from south-western Chesapeake. The motorists are now able to choose a combination of I-464, the High Rise Bridge, Route 17 and Gilmerton routes to travel between Suffolk and Portsmouth.
NXL provided construction inspection services, was responsible for MOT inspection, Substructure/Superstructure inspections from reinforcing steel, concrete, prestressed concrete pile installation, 5ft Drilled Shafts Installation that includes from the excavation of the shafts with soil classifications, and sounded the bottoms of each shaft prior to concrete placement inside each of the shafts.
Our inspectors also oversaw the environmental issues that arose on the project with dewatering, containment of slurry, and demolition due to working on the river. Construction of the replacement bridge was accomplished in three phases. Phase 1, involved shifting the existing four lanes of traffic to two lanes and constructed the approach spans, 12 foot drilled shafts and 207 foot towers. The mechanical/electrical components were also installed during the phase and the lift span was assembled off-site. The 12 foot shafts are the largest drilled shafts ever constructed in the U.S using the temporary casing method with an oscillator.
Phase 2, the lift span for the new bridge was floated by barge from the off-site assembly location to the project site-a process that required a 14-day closure of the existing bridge and a 10-day closure of the harbor channel. Activities included de-constructing and removing the existing bascule leaves and attaching the new lift span to the towers.
Phase 3 required approximately 18 months to demolish the existing bridge and construct the north approach spans. By August 2013, construction was substantially complete with all work completed by January 2014 with a final CQIP score of 93%.
Virginia Department of Transportation