Design-Build Replacement Bridge for St. George Island Protects the Environment and Ensures Durability

摘要

style="text-align: left;">A 4. 1 mile (6.6 km) long, precast, prestressed concrete replacement bridge, belonging to the Florida Department of Transportation (FDOT), was built to provide mainland access to the barrier island  of St. George in the Gulf of Mexico. The $73.4 million bridge is needed to accommodate sensitive environmental restrictions and must provide a 75- year service life with quality production and erection processes for a 10-year warranty from the design-build team. At the time of construction, the two-lane St. George Island Bridge was the single largest design-build project undertaken by the FDOT and when completed in 2004, the 1180 ft (360 m) long, five-span continuous channel span was the longest spliced girder crossing in the United States. In this article, the authors discuss the major advantages  of the design-build approach, the innovative concepts used in the project - including spun-cast cylindrical piles, a new precast concrete bent cap-to-pile connection, stay-in-place precast concrete footing  forms, and bulb tee girders - and how precast concrete design ingenuity led to rapid construction and maximum span lengths while protecting the marine ecosystem. >References style="text-align: left;">1. AASHTO, LFRD Bridge Design Specifications, Second Edition, American Association of State Highway and Transportation Officials, Washington, DC, 1998. style="text-align: left;">2. AASHTO, Standard Specifications  for Highway Bridges, 16th Edition, American Association of State Highway and Transportation Officials, Washington, DC, 1996. style="text-align: left;">3. Issa, Moussa A., a€?Testing of Pile-to-Pile Cap Moment Connection for 30 in. Prestressed Concrete Pipe-Pile,a€? FDOT Report No. 98-9, Tallahassee, FL.