Case Studies 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 on budget.

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