The Brickell City Centre is a large mixed use facility which includes a five star hotel, luxury condominiums, and high end retail and office space located in Miami, Florida. The project occupies three city blocks (8 acres) and includes two levels of below grade parking; a rarity in South Florida. Additionally, two tunnels were constructed below city streets to expand underground parking and allow for traffic to travel below grade across the entire footprint of the property.
After evaluating competing options of ground freezing and tremie seal to create a dry excavation, the owner accepted Malcolm’s proposed deep soil mixing system (DSM) solution for the project. The DSM bottom seal, or “plug,” is comprised of overlapping soil mix columns extending to depths below the bottom of the planned building excavation. In constructing this plug, every square inch of the site was treated with DSM. A sheet pile wall was installed in wet DSM columns to act as both, the support of excavation and permanent foundation wall. Continuous flight auger (CFA) piles, one-third of which extended to depths beyond 100 feet were installed with Malcolm’s BG50 hydraulic drill rig, the largest and strongest fix mast drill of its type in the world. Top down construction was used to build the larger of the two tunnels on the project which extended the full width of South Miami Avenue; a major Miami transportation artery. The second tunnel was constructed in cut and cover fashion using temporary bridges to maintain traffic flow.
