Pumping Down Under In New York City
East Side Access is one of the largest transportation infrastructure projects currently underway in the United States with a history that reaches back to the 1950’s. The project encompasses work in multiple locations in Manhattan, Queens and the Bronx and includes more than 11 miles of tunneling. Concrete work is underway to create subway platforms and passenger walkways in two large caverns that will become double-deck stations for the Long Island Railroad. Our Rental Corp., Babylon, NY is providing efficiencies using a truck-mounted concrete pump with a unique boom 150-feet below Grand Central Station. ACPA member Our Rental is an arm of Ruttura and Sons Construction in Farmingdale, NY, a family-owned business that will celebrate its 100-year anniversary in 2018.
Using a variety of techniques and equipment, the dense bedrock beneath Manhattan and the soil under Queens has been excavated and cleared to make room for the new train tunnels, platforms, service facilities and ventilation and access shafts. Techniques included tunnel boring, cut-and-cover, drilling and blasting. Concrete pumping is currently underway in two caverns measuring approximately 75-feet high, 55-feet wide and 1,200-feet long. Scott Montgomery, Our Rental operator for 10 years has been on the project for more than a year and a half. “When we initially were awarded this contract, we purchased a small 25-meter that didn’t have the reach to cover pours on the opposite side of the tunnel from one set-up,” he explains. Montgomery is constantly maneuvering the pump through the underground of maze of tunnels.
“We realized that the solution to higher efficiency on the project was a pump we already have in our fleet,” explains Nick Avella, Our Rental sales manager, “In fact we have four of the Schwing S 31 XT truck mounted concrete pumps with telescoping booms.” The company utilizes the unique boom on the 31-meter for repair work, indoor pours, under bridge decks and on mezzanines. “It’s the most popular pump in our yard. Customers request it by name,” Avella adds. The machine has a five-section XT boom that incorporate 15’3” of telescoping action. It also has over 830-degrees of boom articulation including a 278-degree Z-tip section. The unfolding height is 18’8” and the machine can reach 87-feet horizontally without exceeding the unfolding height and still pour back to the front bumper. “We have been able to stay on schedule with the 31XT, “ Montgomery states, “Thanks to the booms versatility in the tight confines.”
The machine’s versatility is confirmed by Steve Opitz, Mass Transit Authority senior inspector, “The concrete placement is actually ahead of schedule and the operator is able to maneuver the boom along the wall pours using the telescoping action without folding the other sections which helps with safety and productivity.” Montgomery and another operator, Brian McCoy, are exclusive to the project and the S 31 XT. “These two Manhattan Caverns will eventually house three stories – two levels of train tracks and an entry level joined by elevators – and the space is just going to get more confined. You can be pretty creative with this boom to reach some tight areas.”
The boom pump shuttles to all areas of the two parallel caverns and is fed by three different pumps placed on the surface. Depending on the location of the pour, line length can exceed 2,000-feet. A Schwing SP 4800 is feeding directly into the deck pipe of the S 31 XT. “This keeps the machine cleaner than pumping into the hopper and we only have one man dictating the flow,” Montgomery notes. He utilizes a mine phone, hard-lined to the surface to regulate the flow of the stationary pump which has the ability to apply 2,364 psi on the concrete and output 106 cubic yards per hour. The machine operates in two modes to optimize output or pressure by directing hydraulic flow to the rod side or piston side of the differential cylinders.
“We leap frog throughout the caverns,” according to Montgomery, “We pump while the forms are being stripped in another area.” Pours sizes vary from 150 to 200 yards for the four-feet thick walls that reach a height of 16-feet. Mix designs range from 4,000 to 5,000 psi with metal fibers and 3/8-inch aggregate. “The pumping is going well,” according to Montgomery. The crew starts the day by pumping grout through the line followed by concrete. The initial discharge is placed in a large bucket that is carried by a forklift. Clean up is accomplished with a ball and air compressor. Montgomery performs routine maintenance on the boom pump that hasn’t seen the light of day since it was lowered into an access tunnel and driven to the caverns over a year ago.
When completed, East Side Access will serve approximately 162,000 customers a day, providing a faster and easier commute from Long Island and Queens to the east side of Manhattan. The revised budget for the East Side Access project is $10.178 billion. Revenue service is forecast for December 2022.
“The key to our success on this project is people and equipment,” states Avella, “With responsible operators, reliable equipment in the hole and on the street, I don’t need to go down there.”
Owner: Mass Transit Authority, New York, NY
Concrete Contractor: Michels Corp., New York, NY
Concrete Pumper: Our Rental, Babylon, NY
Pumping Equipment: Schwing S 31 XT truck-mounted concrete pump with placing boom, Schwing SP 4800 stationary pump.