December 22, 2012
This project includes the construction of a 59-span, 4,764' (1,452m), environmentally sensitive replacement bridge for Virginia Route 175 connecting the mainland to Chincoteague Island. The two-lane, 43'-4" (13.2m) wide bridge utilizes typical 80' (24.3m) precast concrete girder spans placed on top of cast-in-place concrete cylinder piles and cast-in-place caps located just under the roadway. The bridge length includes 4,035’ (1,230m) of mainline and 729’ (222m) of a secondary connector bridge providing access to Marsh Island. The navigational channel span is a 92’(28m) single leaf trunnion bascule containing two 123’-6” (37.64m) steel bascule girders 10’-7” (3.23m) deep. The weight of the structural steel in the bascule span is 417,460 pounds (189,000kg). There were approximately 292 piles driven on this project. All were 36" concrete cylinder piles with a 6.5" wall. Pile lengths varied from 84’ to 108’. The majority of the piles were driven to a tip elevation of -85+/-. However, 61 piles were driven to a final tip elevation of -129 by using a follower 30’ long. This is the first instance of a hollow cylinder pile driven 25’ underwater. Also included in the contract was the demolition of the existing bridge.