Alpha Foundations was contacted by General Contractor Culpepper Construction to install Drive Rite™ 2500 Series 2-7/8" Schedule 40 Helical Pipe Piles at the Water Street Marina in Apalachicola, Florida.
Alpha Foundations reviewed the soil information and found the top 12’ of soil was loose sand. From 12’ to a depth of 55 was extremely loose clay (N value of 0), followed by a very dense layer of lime rock. These poor soil conditions made building a dock impractical for typical wood or concrete piles because there embedment depth would need to be 55’ deep.
Alpha Foundations installed 55 helical piles for this dock to an embedment depth of 21’. A 7 helix arrangement was used to overcome the poor soil conditions. The piles were installed to 3,000 foot/ pounds of torque which provided a pile with an ultimate capacity of 27 kips (27,000 pounds) per pile. The piles were fastened to the boardwalk with a typical saddle bracket (shown to the right).
These conditions also made it necessary to install 18 helical piles under the swimming pool. These piles had a 7 helix arrangement and were installed to 8,000 foot/pounds of torque which provided a pile with an ultimate capacity of 72 kips per pile. The pile caps were embedded in the center of the foundation.
It was also necessary to install 4 helical piles to support the sewer buffer tank which weighed 130,000 pounds. The tank was set directly on top of the helical piles. The entire project took 4 days to complete.