Cutter Soil Mixing and Augered-Cast-in-Place Piling Close to the Gulf of Mexico-Paper

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The Marco Island Marriott renovation replaced part of an existing hotel with a ten-story tower, requiring deep foundations and excavations up to 15 feet below ground. BAUER Foundation Corp. installed approximately 36,500 square feet of Cutter Soil Mixing (CSM) support-of-excavation wall and 1,562 augered-cast-in-place (ACIP) piles.<br /><br />The CSM wall was selected for its stiffness and low-vibration installation near occupied buildings. Its flexible alignment allowed crews to avoid undocumented piles, utilities, and other obstructions. Although some samples at depth had lower-than-designed strength, testing and engineering review showed the wall was acceptable. The excavation was completed successfully, and the wall performed well.<br /><br />ACIP piling encountered difficult ground conditions: loose sands, soft soils, tidal groundwater, and shell-and-gravel lenses connected to the Gulf. These conditions caused grout losses, overages exceeding 400% in some areas, and several ground collapses. BAUER adjusted its grouting procedure and installed piles first along the Gulf-side perimeter. This improved ground conditions around the site, reduced grout takes to an average of about 150% of theoretical volume, and prevented further collapses. Micropiles were also used to support a load test after a reaction pile failed.<br /><br />Heavy seasonal rain exposed weaknesses in the unstoned working platform, delaying production until the area was dewatered, regraded, and surfaced with stone. Reinforcement-cage placement was simplified from many configurations to three options, improving speed and reducing installation errors.<br /><br />The project demonstrates how adaptable construction methods, field adjustments, and coordination can address unexpected obstructions and challenging ground conditions while maintaining a demanding schedule.

Keywords

Marco Island Marriott

renovation project

deep foundations

Cutter Soil Mixing

support of excavation

augered cast in place piles

groundwater conditions

micropiles

construction challenges

foundation engineering