Deep Foundation Shoring in South Florida-Paper

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The paper presents the shoring design for the Naples Bay Center, a deep excavation in Naples, Florida, for a mixed-use development with underground parking. The excavation is approximately 374 by 164 feet and 27 feet 8 inches deep, with groundwater about 6 feet below grade. Site constraints and the high cost of dewatering led to a two-phase construction plan that keeps groundwater in place during excavation and bracing.<br /><br />The system uses 630 sheet piles, supported by pre-engineered hydraulic Super Powerbrace Plus wales and Mega Struts. Drilled shafts serve as both the building foundation and columns. After excavation and installation of the bracing, a 4-foot-thick tremie seal slab is placed underwater. The excavation can then be dewatered, and the permanent foundation slabs and walls are constructed against the sheet piles.<br /><br />Coulomb earth-pressure theory was selected because predicted wall movement was considered sufficient to mobilize active soil pressure and wall friction. Soil–structure interaction and bracing loads were analyzed using proprietary modeling software and finite-element analysis, with elastoplastic springs representing soil support. The design also evaluates sheet-pile and frame strength, including wale bending, shear, buckling, and strut forces.<br /><br />Building Information Modeling (BIM) supports coordination, visualization, equipment lists, and fabrication drawings; animation and virtual reality illustrate the construction sequence. LIVEPin instruments in the struts will transmit load data during construction, allowing measured forces to be compared with model predictions, trigger alerts if loads exceed thresholds, and refine design assumptions. The project demonstrates how phased construction, hydraulic bracing, digital design tools, and monitoring can support a complex excavation while minimizing the need for pre-seal-slab dewatering.

Keywords

deep excavation

sheet piles

hydraulic bracing

groundwater control

tremie seal slab

finite element analysis

soil-structure interaction

building information modeling

Coulomb earth-pressure theory

structural monitoring