Sunset Key is a single family villa waterfront community of 47 single family units set on a twenty-two-acre island of land situated in Punta Gorda, Florida. The villas are located within Burnt Store Marina on Charlotte Harbor and the west end of Punta Gorda Isles. It lies at the heart of the island’s exclusive and ultra-private gated community of Prosperity Point.
Amenities include, private canal-side dockage for each individual home within the marina basin. Not incidental is the property’s proximity to some of the best dolphin and manatee watching in Southwest Florida.
Concrete seawalls are structures in our coastal areas that provide shoreline and slope protections. Although appropriately constructed seawalls follow specific engineered designs to withstand caustic marine environments, severe weather can place unexpected stress on a seawall. A prolonged period of heavy rain and the crashing of storm waves created dramatic pressure on the Sunset Key seawall. This powerful force was created by Hurricane Irma.
In addition, once the eye of the storm passed there was a dramatic tide event which drained all the water out of Charlotte Harbor. This created a catastrophic event which triggered 1,200 lineal foot of seawall to fail and collapse.
The aging seawall lies in close proximity to the Gulf of Mexico and constant coastal erosion and lack of maintenance assisted the total failure. There was a ten foot wide sidewalk, upland retaining wall and various underground utilities which prohibited use of conventional tie-backs/dead-men for the project.
Coastal Foundation Solutions was contacted by marine contractor, FMC to install Seawall Saver 1 ½” square shaft helical tieback anchors for the Sunset Key Villas development at Punta Gorda, Florida
The requirement for an engineered and reliable method that could attain the load requirements of the seawall project left helical piles as the only remaining option. The ability of Coastal Foundation Solutions to mobilize floating equipment and prepare for the quick helical anchor installation allowed the project to move forward without additional costly delays.
The helical tie-back anchors were installed to support the new concrete seawall being installed within certain portions of the waterfront villa community.
Our engineers reviewed the existing soil boring information and determined that a helical configuration of 10″-12″ was necessary to generate the required torque rating of 1,400 foot-pounds in tension.
The pile depths ranged from 21’ to 28’ in depth. Upon completion of the helical pile installation, couplings and terminations were provided for final embedment into seawall cap.
One two hundred twenty-five (225) Seawall Saver (1-1/2-inch square bar) helical tieback anchors with a 10”-12”- double-helix lead section was installed beneath utilities, sidewalks and retaining walls. The Caterpillar 305 CR excavator with a specialized mast system powered by a 10k Pro-Dig drive head was utilized to install the anchors. Seawall Saver Helical extensions embedded the tieback anchors to lengths of 21 to 28 feet to attain final installation torques.
The helical tieback anchors were hydraulically rotated to 2,000 P.S.I., providing a tension load of 12 kips.
Two hundred twenty-five (225) Seawall Saver (1-1/2 inch square bar) helical tieback anchors with a 10”-12”- double-helix lead sections.
Five-hundred sixty-two (562) additional extensions were used to attain dynamic load capacity due to sub-surface soil disparities.
The helical tie back anchor was linked to a hot dipped galvanized steel channel, placed within the new seawall cap to provide lateral structural support. All tiebacks and anchors were load tested with a 30-ton center pull ram to secure required engineered load capacity.
This project was completed over a 3 month period by our team.