Miami Tunnel Starts with Marathon Platform Pour
The competitive construction market in Miami is a challenge for any pump company, even without the unpredictable weather and site surroundings. Temperatures reaching 95-degrees, 100% humidity, and consistent rain make for unfavorable work conditions. The Port of Miami Tunnel project consists of twin underwater tunnels with an entrance sandwiched in between 6 lanes of traffic. The job required Florida Concrete Unlimited to unexpectedly install 1,000-feet of slickline on two day notice, to access all areas of the 1,000’ x 80’ pour site, and pump into multiple booms to complete the project. Add the fact that not one hick-up could be afforded without causing a catastrophe and this is a story worth telling!
“We love to do the things that intimidate others, it’s just in our blood,” explains Jason Goff, the second generation of Florida Concrete Unlimited, Inc.(FCU) The company is an ACPA members with headquarters in Miami, and various locations throughout the state of Florida. “Most pumping companies in the area were not capable of performing this job based on equipment demands and timelines. FCU finished it on-time by thinking outside of the box, and ahead of the game.” This was one of the first large concrete pours for the Port of Miami Tunnel (POMT) – a nearly one mile tunnel under the manmade Government Cut shipping channel between Miami Beach and Fisher Island.
The 9,000 yard platform will support a Tunnel Boring Machine (TBM) which will excavate twin tunnels to provide increased access to the Port of Miami. The $45 million, 2,500 ton TBM arrived from Germany where it was specifically designed for the largest public works project in South Florida. The 380-foot long machine is 4-stories tall and will bore the 43-foot diameter tunnels specified by the owners of the project. According to the public/private partnership Florida Department of Transportation (FDOT), Miami-Dade County and the City of Miami, this project will not only provide direct access between the seaport and highways I-395 and I-95, but create another entry to the Port of Miami. The Port of Miami is the community’s second largest economic generator.
In preparation for boring in the Fall, the platform was constructed in July. Sheet pilings encased the area which was under water necessitating a tremie pour. The funnel to the 50-foot tremie pipe was set on a floating raft which was maneuvered by cables providing one point of placement for the pump operators. Originally ready-mix access was planned along one side of the pour area for Florida Concrete’s Schwing boom pumps which included two S 61 SXs, two KVM 39 X and a KVM 41X assigned to the project. When project personnel realized that the tight job site, which is sandwiched between six lanes of existing freeway traffic, would not allow truck mixers to reach the pumps, a new plan was hatched. “We had to go pump-to-pump because ready-mix access was now restricted to one end of the pour, “ explains Goff.
Normally acquiring 1,000-feet of five inch system would be a tough call on short notice. But Florida Concrete is one of the leaders in south Florida high-rise construction. The 37-year old pump, place and finish contractor has 15 placing booms and thousands of feet of system on hand waiting for condo and commercial construction to come back to the area. The firm also provided the manpower to form and pour the thrust blocks to contain the system along the side of the pour area.
The company’s two S 61 SXs pumped out one end of the rectangle with 184’2” of horizontal reach and Super X outriggers that allowed maximum utilization of the booms. The curved Super X outriggers telescope along the sides of the pump sub frame and provide excellent stability while projecting only slightly ahead of the truck bumper. Then one of the S 61 X was moved to the opposite end of the rectangle and a Schwing KVM 39 X was moved into place to provide the primary pumping power to supply ready-mix to a Schwing KVM 41X and then another 39X in the middle of the pour area.
The KVM 39 X is equipped with a 2023/5 pumpkit with 9-inch pumping cylinders and 79-inch stroke length. The pumpkit has the ability to be easily changed from a high volume pump with up to 210 cubic yards per hour output pumping on the rod side of the 5.1” diameter differential cylinders to a high pressure pump where hydraulic pressure is applied to the piston side of the differential cylinders. This gives the pump the ability to place concrete at longer distances. Goff elected to switch the pump to the high pressure setting in anticipation of the long push that would ensue when the pipeline was stretched to its full length and pumping would be through the boom of the S 61 SX adding 171’9”-feet of horizontal reach.
From the time the 39X went online FCU averaged 110 yards per hour for 58 continuous hours. Pumping continued straight out the back of the KVM 39X’s discharge end and through the 41X then another 39X and finally a S 61SX. As the pipeline was extended to the 39X and the S 61 SX a diversion valve and priming T was installed to allow the new sections to be primed without having to blow back the line, this was critical as the pour could only be interrupted for five minutes. The pipeline was hooked directly to the deck pipe of the receiving pumps. More than 58 hours of pumping continued in this manner, of the 89 hour pour.
On July 7th the final push began with the KVM 39X feeding the boom of the S 61 SX for 15 straight hours maintaining 100 cubic yards per hour. “Even with the high ambient temperatures and pumping through nearly 1,000-feet of system the pump never exceeded 60 degrees Celsius and pressure’s remained below 200bar, “ explains Goff, “We slowed the number of strokes per minute by switching the pump kit to piston side which kept the temperature in check while keeping adequate concrete pressure to maintain volume.” While the pumps continued non-stop, Goff rotated operators every 8-hours. Divers monitored the pour progress continuously.
“Concrete pumps can do the unimaginable with the right direction and properly trained personnel. I have a high amount of confidence in Schwing’s equipment and even more in my staff. I had the luxury an extremely seasoned team and 40 year veteran Eddie Gillespie at the helm for the entire 89 hours. If I had to describe the pour in one word it would be, FLAWLESS!”, says Goff.
The platform for the TBM is the first step in a four year project that will see the twin tunnels relieving traffic in the downtown core while keeping the Port of Miami vital. It is estimated that the Port generates 81,000 jobs and $12 billion in economic output for the Miami area making it one of the largest wage and revenue providers in the area.
Owner: Florida Department of Transportation (FDOT),
Miami-Dade County and The City of Miami.
General Contractor: Bouygues Civil Works Florida, Miami
Pumping Contractor: Florida Concrete Unlimited, Miami
Pumping Equipment: Schwing Two KVM 39X, KVM 41X and two S 61 SX truck-mounted concrete pumps with placing booms