With millions of cruise-goers passing through the port on an annual basis, the Port of Miami is home to five major cruise lines. It is also one of the world’s largest hubs for cargo-related commerce.
The Port of Miami project, later renamed PortMiami, was designed to help alleviate the staggering amount of both traveler and cargo-related traffic going into the port. A project three decades in the making, a new, underwater twin tunnel would provide direct access between the seaport and Interstates 395 and 95 and also reduce the amount of cargo-related traffic.
A specially designed, 43-foot Herrenknecht EPB TBM was created for the project to create what would be, at the time, the largest bored tunnel in North America.
Nicholson’s portion of the work also won the Deep Foundation Institute’s Inaugural Bermingham Innovation Award.
After further investigation of the tunnel alignment and the
local ground conditions, it was determined that grouting was needed in the Key
Largo formation through which the TBM would mine. The Key Largo formation is a
notoriously unstable and porous coralline limestone.
Nicholson was awarded the specialty grouting contract for both onshore and offshore operation, which included filling voids ahead of Harriet, the project’s massive TBM.
Part of the work was performed at Watson Island, while the other portion was performed off-shore in the channel between Watson Island and PortMiami. This off-shore work, which was performed on barges, had to be carefully coordinated with the Port’s busy schedule.
The offshore drilling also had to be performed under a double-confinement system in order to avoid polluting the waters of the channel.
The environmental protections created an interesting challenge for the off-shore drilling operation. A 70-foot buffer had to be maintained from the operation to the shoreline. This buffer required the innovative use of a pipeline bridge used to bring grout from the onshore batching plant to the offshore equipment.
Collaboration with sister company Bermingham Foundation Solutions yielded a proprietary drilling and grouting system that used the same drill string to drill and grout in a single stroke. This saved drill changing and tooling times that would normally be required.
Technical challenges aside, the biggest hurdle to overcome on the project was working around the active cruise ship schedule. When ships came in, all of Nicholson’s barges, which could include up to ten a week, had to be demobilized.
In total, drilled more than 1,000 grout holes and about
93,000 linear feet of grouting, for a total estimated volume of 65,000 cubic
yards of grout.
Due to the complex nature of the project, the drilling operation was closely monitored using Grout I.T., a proprietary, real-time control and data collection system created by Nicholson’s parent company, Soletanche Bachy.
The PortMiami Tunnel officially opened for business August 3, 2014. The successful completion of the project marks one of the country’s first public-private partnerships that will use an availability payment contracting structure. The project won numerous awards, including the America’s Transportation Award in 2015.