Putzmeister Trailer Pump Has the Size and Muscle To Pour a High-Rise Building in Crowded Chicago June 2001

Although already crowded with skyscrapers, downtown Chicago keeps making room for even more high-rise structures. The latest one under development is Columbus Towers. After completing its 6-floor parking garage, a 52-story apartment building will follow for a total of 58 stories. The lower floors will be ready for initial occupancy next spring, with final completion scheduled for next fall.

Keeping in line with the fast pace of the Windy City, this particular contract is calling for an unbelievably fast completion as well. It requires one apartment floor to be placed every three days in comparison to the more common five to six day schedule per floor. Added to this challenge is the fact that the structure going up is in a very tight area on Columbus Drive bordered by bridges on three sides and another high-rise on the fourth.

"Because of the close quarters and height, we had to use a trailer pump rather than a truck-mounted boom pump, and one with enough power to get the very dense, high-strength concrete up that high," said Selton "Sam" Sampson, concrete superintendent with James McHugh Construction in Chicago, the general contractor. "This concrete is much harder to push than normal-weight concrete."

To push the concrete, Sampson is using a Putzmeister BSA 14000 HP-D trailer pump, which is capable of pumping 134 cubic yards an hour (102m3/hr) at 2176-psi (150 bar). The unit is pumping concrete to a 38-Meter Putzmeister placing boom attached to a square placing tower supported by a Putzmeister adjustable wall bracket.

Placing boom facilitates quick moves This unique combination of equipment helped keep the project on its fast track. Putzmeister recently introduced the 38-Meter as the largest placing boom on the market that doesn't require counterweight. McHugh found its extensive 111-foot (34m) horizontal reach a necessity for the greatest coverage and its light weight important for using on-site crane capacity. Plus, moves could be done quickly without the hassle of counterweight, which saved time … a precious commodity with this specific job.

Putzmeister worked in conjunction with McHugh and Periforms, the formwork supplier, to develop a new, adjustable version of their existing wall bracket to accommodate the larger sized 38-Meter placing boom. Plus, the adjustable feature would make lifts easier with a bottom connection that had an adjustable range of 12 inches (305mm) for better lining up with the concrete embeds.

The newly designed wall bracket proved its worth. It was attached to the side of an elevator shaft, but not anchored to the formwork. This meant no vibration to the forms for a far superior finished product and reduced wear and tear on the forms for cost savings. Setup and disassembly was also quick and easy, as the wall bracket was easily raised with the forming system when it was elevated. If preferred, it could have also been raised by crane.

As a result of this successful joint development, the new adjustable version is now the "standard" style of the Putzmeister wall bracket. This same bracket can be used with all Putzmeister America separate placing boom models, no matter what the boom weighs. It can additionally be used with any manufacturer's brand of self-jacking forms on the market. In this situation, it moved the job along at an accelerated pace.

Will pour a total of 38,000 yards "We're using about 350 cubic yards (268m3) of concrete for each apartment floor," said Sampson. "Including the parking area, we'll eventually pour more than 38,000 cubic yards (29,053m3) before we're finished."

As noted, five or six days are allowed to pour each floor in normal high-rise construction schedules, so the pace of one floor every three days after the parking floors are finished doesn't leave a lot of room for error. Andres Pantoja, the labor superintendent on the job who supervises about 25 laborers, said his 12-man concrete crew is highly experienced. "Fortunately, the key people in this crew each has about 15 years of experience," said Pantoja, who has been in construction for more than 25 years. "They know how important it is for everyone to be on the same page at all times and working together to meet the target of three days a floor. At this pace, we can't afford to have people who have never worked with concrete, especially hundreds of feet off the ground."

Pantoja added that the smooth operation of the Putzmeister placing boom and the long strokes of the trailer pump help to make the concrete placement both safe and efficient.

"It's perfect for the job" "I can't say enough about that trailer pump," said Sampson. "It's perfect for a job in downtown Chicago where you don't have a lot of space and yet have to go up pretty high." He had used a Putzmeister trailer pump to pour the floors of the new 74-story Park Hyatt, located on Michigan Avenue in Chicago's historic Water Tower Square. The hotel opened in June 2000.

For that job, he had rented the pump from Hoyer Warner Equipment, a Putzmeister dealer in Bensenville, Ill. "After seeing what it could do, and because of the jobs we had coming up, I decided to buy one."

Sampson said the trailer pump would be put to good use in the months ahead because their job plate is full for some time to come. "The economic slowdown hasn't affected commercial building yet as far as we're concerned," he said. "It may down the road, but right now that trailer pump will pay for itself in a very short time."

They started the concrete pour for the parking garage last August, and the building is expected to be completely finished by the fall of 2002.

Chicago High-Rise JOB SPECS: Owner: Charles E. Smith Residential Realty, Arlington, Va. Architect: Loewenberg Associates, Chicago General contractor: James McHugh Construction, Chicago Ready-mix supplier: Prairie Material Sales, Chicago Equipment dealer: Hoyer Warner Equipment, Bensenville, Ill. Equipment: Putzmeister BSA 14000 trailer pump, Putzmeister 38-Meter placing boom, and Putzmeister adjustable wall bracket.