The St. George Island Bridge Replacement Project is one of the largest design-build efforts undertaken by the FDOT. This project featured a 21,615-foot long bridge (4.1 miles; 166 spans) over Apalachicola Bay in some of the most environmentally sensitive waters in North America. Apalachicola Bay accounts for 90% of the oyster harvest in Florida and is home to several endangered species. The old bridge is a primary evacuation route that needed substantial repair due to several structural deficiencies.

The new design provided for a wider bridge deck with two travel lanes of 12 feet width, and two safety lanes 10 feet wide. A key element of the design used new, high capacity 54-inch diameter, precast cylinder piles with precast concrete caps. These piles are expected to last more than 100 years in the harsh saline environment and offered the best foundation alternative with fewer piles and the least environmental impact.

H2R Corp, formerly Williams Earth Sciences, Inc., as the geotechnical consultant, performed all of the subsurface explorations and provided foundation recommendations. Using a barge-mounted drill rig, 49 borings were performed over water, along with 128 cone penetrometer soundings. Dynamic pile testing of 56 test and 520 production piles during construction was also performed.