St. Johns Ship Building
St. Johns Ship Building, Inc., a full service ship building and marine
repair company in Palatka, Florida, developed plans to install an addition
to the existing tug boat fabrication area, increasing their current fabrication
space by an additional 11,000 ft².
Problem: The entire fabrication area would then be enclosed with a metal building
and have built-in rails for sliding the ships into the river once they’re
assembled. Located about 30 miles from the Florida coast and along the
St. Johns River, the shipyard’s addition had to be designed for
both compression and tension based on the wind loads and the possibility
of hurricane force winds in that region of Florida.
Proposed Solution: The designers of the new facility, Robert E. Taylor, AIA, PA and Conestoga
- Rovers & Associates, proposed the use of Ram Jack’s 8”/10”/12”
multi-helix piles in the foundation of the building. Based on the soil
information collected and the calculated loads of both the building and
the ships that would be assembled in the fabrication area, the design
called for helical piles with a 72 kip ultimate capacity. This foundation
design called for two (2) helical piles with new construction brackets
to be placed in each of the (21) 4 ft. x 4 ft. x 20 in. footings to carry
and hold the projected loads of dead, live, and wind loads.
Outcome: All 42 helical piles were installed over a three-day period to an average
depth of 31ft. with 8,000 ft-lbs. of torque using a Bobcat 341 mini-excavator
and a two-person crew. The installation proceeded without problems and
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