May 19, 2014, marked the opening celebration ceremony for the Port of Miami Tunnel Project. Hundreds of construction workers and project staff walked out of the tunnel in a special parade with over 1,200 guests, media and dignitaries. Special guests included: Governor Rick Scott, Lt. Governor Carlos Lopez-Cantera, U.S. Secretary of Transportation Anthony Foxx, State Secretary of Transportation Anath Prasad, FDOT District Secretary Gus Pego, Miami-Dade County Mayor Carlos Gimenez, City of Miami Mayor Tomas Regalado, PortMiami Director Juan Kuryla and Former Port Director Bill Johnson.
This $1.2 billion project is undergoing final testing and will soon open to traffic connecting PortMiami directly to the interstate highway system alleviating traffic congestion in downtown Miami, improving quality of life and promoting development while keeping PortMiami competitive.
The project, which was built for the Florida Department of Transportation at an estimated design and construction cost of $667 million, includes 0.75-mile long twin-tube highway tunnels connecting the MacArthur Causeway on Watson Island to PortMiami on Dodge Island. The tunnel was excavated using a 42-ft Herrenknecht Mixshield TBM, which was considered the largest soft ground TBM bored to date in North America.
The TBM used an innovative water pressure balance/control mode in addition to the classical EPB mode. Approximately 751 concrete tunnel lining rings were installed in the 4,186 lf bored Eastbound Tunnel and approximately 745 rings were installed in the 4,152 lf bored Westbound Tunnel.
Five cross passages were built between the two tunnels. Due to the highly permeable nature of the soil, pretreatment was required. The first, fourth and fifth cross passages were not located underneath the channel, so they were pretreated from ground surface using cutter-soil mixing panels that form a grouted block of soil that were excavated. A first for Florida, a ground freezing method was used for the other two cross passages, which go underneath Biscayne Bay, and were treated with a brine to freeze the ground, before excavation was done. Freezing process included the installation of a total of 44 freezing pipes. Estimated freeze time once brine was installed at -22 F was about 40 days. A small cooling unit was installed in the second tunnel to cool the lining segments and ensure efficient closing of ice ring. Steel support frame was installed to prevent movements of the first tunnel due to ice pressures and a steel door was installed as “fail safe” to be closed in case of an emergency during excavation. All cross passages were successfully excavated.
The project was delivered using a public-private partnership between FDOT and MAT Concessionaire LLC (MAT), which hired Bouygues Civil Works Florida (BCWF) to design and build the project.