Concrete Products

SEP 2015

Concrete Products covers the issues that attract producers of ready mixed and manufactured concrete focusing on equipment and material technology, market development and management topics.

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www.concreteproducts.com September 2015 • 33 FEATURE COVER STORY Bayshore Concrete Products has fabricated 60 foot- er boxes for approach span pile caps at its 90-acre, Cape Charles, Va., facility. The tubs are produced in four sizes, the smallest of which are 30- x 73-ft., weighing 320 tons, up to 36- x 84-ft., weighing 490 tons. "We can stage up to 13 units," says Bayshore Plant Manager Chuck Hook, "and we send two units per barge in tandem tow, with about a 10-day turnaround." A subcontractor ties reinforcing cages on site using four truckloads of galvanized steel or stainless steel rebar, the latter specified where the pier will be below the water- line due to micro-flexing of the tub at high tide. Bayshore's fab shop built the steel tub forms. "First we pour the floor, 106 yards," says Hook. "The next day, we pour the walls." The initial pour takes 3.5 to four hours using pump trucks, notes Bayshore's TZC Project Manager Thom- as James. On the second day the walls are poured. After curing, a waterproofing epoxy is applied to the floor-wall joint. Finally, robust plastic fendering systems are bolted in place. The finished tub has cylindrical holes in its floor that allow a 9-in. gap around the piles. A 600-ton, rubber-tired gantry crane was rented for the project to transport the finished tubs through the bustling yard to the staging area and barge slip. Bayshore Concrete approached mid-2015 with production and ship- ping on schedule, tub fabrication wrapping up by August. MIXING & TESTING New NY Bridge precast and cast-in-place concrete struc- tures have common equipment: BHS twin-shaft mixers at TZC's three floating plants at the job site, and at the Bayshore and Coastal precast batch plants. Bayshore's two twin-shaft models on line in 2008, replacing pan mixers in a Standley Batch Systems plant long on storage of a wide range of cementitious materials and aggregates. The mix- ers produce 5.5-yd. batches, discharging into Tuckerbilt sidewinders or Bayshore's fleet of eight 12-yd. front-dis- charge mixer trucks. Every load is tested and, as with Coastal Precast, a New York State Thruway inspector has been on site full time. "We had several different mix designs on file, with and without silica fume, and we tried several different fly ashes to see which would perform best," says James. "We always use the silica fume in the walls, but we only used [it] on the floors in the winter to get the little extra boost in strength that we needed." Previously dosing it by the bag, Bayshore added a silo dedicated to silica fume and conveyed the ultra fine pow- der to a spare water batcher prior to discharge into the mixers. A seven-day wet cure was required, with a target of 6,000 psi. Form removal could occur at 2,500 psi, and picking at 4,000 psi. Bayshore had to widen its barge slip from 58 to 62 feet to accommodate the TZC precast footer boxes. A new cast- ing line, complete with fabric-enclosed, open-truss frame structures, consumed former storage area. "Once the TZC contract was awarded," says Hook, "we excavated new footers and poured a 400-foot soffit, and fabricated the steel formwork in house. For the crane's path to the pier, we excavated and put in 40 inches of compacted material." About 35 to 40 personnel were added for the TZC project, he adds, though it was only one of three large projects that swelled employee ranks from 58 to 400 in one year. Continued on page 34

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