Prosperity Pointe Island Pool Bulkhead Replacement

ClientProsperity Pointe Island Pool
LocationPunta Gorda, Florida

Wooden Bulkhead Replacement For Burnt Store Marina

Located on stunning Charlotte Harbor is Burnt Store Marina a prime waterfront location for avid sail boaters. There are numerous luxury waterfront villas and condominiums situated within the adjacent Sunset key and Prosperity Pointe development. A charming amenity is a community swimming pool located on a island with only pedestrian bridge traffic for pool access.

The deluxe swimming pool and bathhouse has a 25 year old wood retaining wall which is failing. The entire deck and surrounding spa has brick pavers throughout and concrete sidewalks.

Project Challenges

The project team encountered a number of methodology challenges including construction in a sensitive, limited construction access within dense villa and condominium environment, and difficult subsurface soil conditions (sub-surface rock) that are commonly found in this specific location.

The scope of work entailed being a subcontractor to Benton and Sons to install seventy-eight (78) helical tieback anchors to sustain a new “Trueline” vinyl seawall. Helical Tie-Back Anchors on the project site were engineered to twenty (20) kips ultimate load, however the site provided numerous challenges. Remnants of previous structures, such as buried concrete tie-backs, submerged cables and large buried concrete masses, were present behind the wall to additionally complicate the previously challenging subsurface circumstances. In addition, we had to utilize a 100 ton crane to mobilize our barge and support equipment into lake.

Project Solution

The project team explored several piling options, timber piles, drilled micropiles, concrete pre-stressed piling and helical piles.

Helical Anchor Piling (tie-backs), were both an attractive selection due to limited access, subtle vibration, and reasonably affordable cost. The Seawall Savers Team decisively selected helical piles as the most suitable and cost-effective tie-back anchor favorite for the project. It provided owners a low-noise and minimal vibration project for adjoining neighbors.

The final pile engineering was performed by Rube Clausen Consulting and featured a galvanized 1 ½” steel square shaft section manufactured by “Chance”. The piles consisted of a 1 ½”inch sq. shaft with triple-helix (8”/10”/12”) lead sections. The tie-back helical anchors were engineered to derive end-bearing capacity in the dense soil layer.

Helical Pile Installation

Before the installation of production piles, the General Contractor, Benton and Sons Marine Construction, eliminated potential obstacles, such as partial removal of pedestrian bridges, including utilities. This would allow for barge access around the island.

Upon helical piling termination, all helical piles were cut to their required length. Pile production included a full-time Quality Control person to oversee pile testing and installation. Pile monitoring and certification was performed by Forge Engineering of Naples, Florida.

The helical piles were installed by Seawall Savers (SS), a Certified Installer of “CHANCE” Helical Foundations Systems.


Sixty (78) “CHANCE” 1 ½” square shaft with triple-helix (8-inch/10-inch/12-inch) lead sections were installed. The foundation helicals were embedded with a Caterpillar 311 excavator powered by a 10K Pro-Dig hydraulic drive head. Seawall Savers advanced the foundation anchors to lengths on the order of 15 to 21 feet to achieve final installation torque. The ultimate required load bearing in tension was 36 KPS.

• Install seventy-eight (78) SS5 galvanized helical tie-back anchors

Utilize one hundred twenty-two (122) SS5 1 ½” extensions

• The helical anchor pilings were affixed with a galvanized 7’ by 7” termination cap.

Project Summary:

• Geotechnical Engineer: Forge Engineering
• Structural Engineer: Ruben Clausen Consulting
• General Contractor: Benton and Sons Contracting
• Piling Monitor: Forge Engineering
• Certified Installer: Seawall Savers

Key Advantages:

• Restrained entry
• Dedicated hydraulic equipment for helical piling projects
• No earth removal
• Verification testing with Digital Torque Indicator
• Secure pile embedment into fractured lime-rock
• Effectively no pulsation/noise

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