Post girder-erection work continues at the Corps of Engineers/Jacksonville District's Palm Valley Replacement Bridge along St. John's County Road 210 in northern Florida. The project challenged Standard Concrete Products, Inc. to fabricate mammoth haunched beam girders — 141 ft. long, tapering from 15 ft. tall in the middle to 96 in. on the ends — placed along three main spans over the Intercoastal Waterway.

The producer handled the 146-piece contract from its Savannah, Ga., and Tampa, Fla., operations. The latter supplied conventional 78-in. Florida Modified 6 Bulb Tee prestressed girders for the six-span east and west approaches. The 119-ft.-long members were trucked to the site, nestled between the Atlantic Coast cities of Jacksonville and St. Augustine.

With easy access to the Atlantic Ocean, the Savannah plant handled the 125-ton haunched beam girders and two other custom members: 148-ft.-long, 96-in.-deep main span drop-in beams and 139-ft.-long, 81-in.-deep end-span beams. Delivered in 10 barge runs, the main-span members are placed eight across and have end-to-end post-tensioning. The spliced girders support a 290-ft. main — with 65-ft. navigational clearance — and 210-ft. end spans.

Standard Concrete built an elevated compression frame pretensioning bed to fabricate the Palm Valley project's 16 haunched girders. The assembly comprised 24-in. prestressed piles (wet cast at Standard/Savannah), raised 17 feet and resting on steel columns with bolted connections, plus a form engineered for easy filling and retooling. To that end, Bonnybrook Custom Steel Forms incorporated in the form a) pour windows to receive concrete from side discharge Tuckerbilts for lower portions of the girders, thus minimizing the drop of mixes from buckets used to fill top portions; and, b) a horizontal joint enabling Standard to repurpose the unit for 96-in. members of more conventional profile, plus a subsequent contract requiring a 12-ft. haunch beam.

A 26-month construction schedule for the Palm Valley Replacement Bridge calls for completion in September 2002. The contractor on the project is Eby Construction Co., Port St. John, Fla.; design engineer is URS Greiner Woodward Clyde, Tampa.