In September of 2017 following the passing of hurricane Irma, Coastal Foundation Solutions was contracted to install supplemental helical tieback anchors to facilitate emergency repairs to an existing seawall structure. Coastal Foundation Solutions sprung into action to quickly and strategically structure a plan to serve the foundation needs of Tin City.
Many businesses took a direct hit from Hurricane Irma at Tin City, an old commercial fishing compound on the Gordon River that has been converted into shops and restaurants. Tin City includes over 32 boutiques and two destination waterside restaurants. Irma sucked the water from Naples Bay, leaving the complex’s sea wall vulnerable to the storm’s pounding rains and hurricane force winds. The storm and violent tides tore away the sea wall to the point of total failure. There was three hundred fifty-four (354) foot of 8” concrete seawall protecting the complex.
The severity of the situation was the water depth at front face of the seawall was ten (10) foot deep. The critical element is that the restaurants proximity (5 foot) to the failing seawall could be catastrophic if the wall collapsed into the river. The owner was extremely concerned that the destination location would be lost.
A phone call was received at Coastal Foundation Solutions very late one Monday afternoon following the destruction from hurricane Irma. The owner explained the critical situation at Tin City and the urgency set our company and barges in motion. Fortunately, we had equipment close by to the project location to facilitate emergency repairs.
Coastal Foundation Solutions met on site with engineers from Turrell Hall and Associates, Existing Structure Engineering, and owner’s representatives to initiate emergency repair plans. Such a complex construction repair relied on a sophisticated anchoring system and this is where Seawall Saver helical anchors were able to impact restorations.
Turrell Hall and Associates located in Naples, Florida in September 2017 awarded Coastal Foundation Solutions a contract for the installation of forty-two (42) supplementary helical tieback anchors and forty-two (42) 12” marine grade piling (bolster piling). CHS along with Byron Evetts P.E. with Existing Structures Engineering calculated a technical plan to preclude any further movement to the existing concrete seawall and stabilize the structure. A Seawall Saver Helical Tie-Back anchor system was selected by the engineer, contractor, and owner’s representative as the preferred method to stabilize the seawall structure. The system was installed by Coastal Foundation Solutions (CFS), a Certified Installer of Seawall Saver Helical Solutions, Located in Matlacha, Florida.
Forty-two (42) Seawall Saver SS150 (1-1/2-inch square bar) helical tieback anchors with a 12”-14” double-helix lead section was installed beneath existing restaurant structures. There was a 10” marine piling driven into river sub-strata to terminate helical anchors into. The 88SR Komatsu excavator, powered by a 10K Pro-Dig drive head was utilized to install the anchors. The wood pilings were installed with an Allied Plate compactor mounted on 210 Kobelco excavator. Seawall Saver Helical extensions imbedded the tieback anchors to lengths of 28 to 35 feet to attain final installation torques.
The helical tieback anchors were hydraulically rotated to 2,700-foot pounds of torque, providing a tension load of 24 kips.
One hundred forty-two (142) additional SS150 extensions were used to attain dynamic load capacity due to engineers specified load capacity. The helical tie back anchor was fastened to a 10” marine grade piling, placed at the outside seawall face to provide additional lateral structural support.