Dunes of Naples located in North Naples, Florida in July 2018 awarded Coastal Foundation Solutions a contract for the installation of eighty-two (82) helical tieback anchors. CHS along with Turrell Hall and Associates designed a system to prevent any further movement to the wood bulkhead alignment. A CHANCE Helical Tie-Back anchor system was chosen by the owner, contractor, and engineer as the desired method to stabilize the seawall structure. The system was installed by Coastal Foundation Solutions (CFS), a Certified Installer of CHANCE Helical Foundations Systems. Coastal Foundation Solutions is located in Matlacha, Florida their service areas include Lee and Collier Counties.
Forty-five (45) CHANCE SS150 (1.5-inch square bar) helical tiebacks with an 8”-10” double-helix lead section was installed through ten-inch diameter core holes in a wood bulkhead using a Kubota KX040 excavator with a specialized mast system powered by a 6K Pro-Dig drive head. Helical extensions advanced the tieback anchors to lengths on the order of 15 to 21 feet to achieve final installation torques, The ultimate capacities of at least twice the design working tension load of 12 kips
Thirty-Seven (37) CHANCE SS150 (1.5-inch square bar) helical Anchors were installed through a combination of 3” thick wood bulkhead and 8” of solid reinforced concrete behind existing wall. Coastal Foundation Solutions utilized combinations of specialized core bits to gain access through existing vertical wall. Anchors were installed to corresponding capacities of working tension load of 12 kips.
Twenty-two (22) additional SS150 extensions were used to achieve required load capacity due to sub-surface soil variations.
The helical anchor was connected to a galvanized steel channel at the outside wall face. The channel bridged 24” with a wood 4” x 6” timber spanning 4’6” from between pilings. The tiebacks anchors were installed approximately two (2) foot down from the top of the wall and at a typical spacing of about five feet O.C. All tiebacks and anchors were load testing with a 30-ton center pull ram to secure required engineered load capacity.
Eighty-Two (82) seawall drains were installed to reduce hydrostatic pressure from upland side of bulkhead.