harbour island plaza

Underpinning and Chemical Grout: Multi-Use Commercial Building, Tampa, FL

In Commercial Projects, Commercial Blog Posts, Featured Projects by John Topa

The Plaza at Harbour Island

Tampa, FL

Foundation Repair for a Multi-Use Complex

Improvement of the clayey sands and silty soils

Micropiles installed to a 45-50 ft depth range

Project PDF


The project is a multi-use complex, including retail space and multi-level condominiums/apartments. The Geotechnical Engineer of Record recommended a foundation repair of underpinning micropiles and chemical grout injections to solve settlement problems.


• Bay bottom sediments of very loose silty to clayey sands and clays with differing silt, sand, and shell content.
• The surface of the limestone formation was encountered between 33 feet and 44 feet.


Helicon worked alongside the geotechnical design team to develop a foundation repair program designed to meet the building code load criteria. Micropiles were installed to a depth range of 45-50 feet below existing grade. The support brackets for the micropiles allow not only prevention of further settlement of foundation elements but also can be utilized to provide some uplift of foundation elements. Chemical grout injections were completed to give additional support to the foundation. Efficient planning & coordination was key to overcoming the challenges & limitations. Helicon collaborated with the Geotechnical Engineer of Record throughout the work and confirmed all recommended criteria were followed. 

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