Project is Model Of Efficiency Aided by Separate Placing Boom 2006

General contractor Adolfson & Peterson Construction, Minneapolis, MN, is nearly a year into construction on a new 291-foot tall building that will expand the downtown Minneapolis skyline into the nearby Elliot Park area. Despite adjusting to separate mixes required for decks, walls and outdoor patios, things are going smoothly thanks to the ready-mix producer and pumper being one and the same. Cemstone, Inc., Mendota, MN chose their Schwing KVM 39 X detachable placing boom to contribute to the efficiency on the project. Skyscape consists of 28 floors of residential and commercial space that is part of the city’s growing downtown community.

The first four floors of the mid-rise will accommodate commercial vendors and parking facilities for residents and patrons, while the remaining 23 will consist of 252 condo units. To access nearly all areas of the first few a-typical floors, Cemstone utilized a KVM 39 X truck-mounted concrete pump with Overhead Roll & Foldä boom design and 127 feet of vertical and over 114 feet of horizontal reach.

The parking structure posed a minor challenge for the supplier/pumper, as rough Minnesota winters translate into automobile tires encrusted with salt and other corrosive chemicals. To ensure the facility will stand the test of time, Cemstone supplied a proprietary mix engineered to hold up under the effects of these caustic substances. Acting under the dual role of supplier and pumper, Cemstone was able to determine not only the correct mix design for the application, but also a way to place the concrete safely and efficiently.

“On every project that calls for both of our divisions, the pump operators, the engineers and the batch plant personnel are constantly communicating,” says Mike Beagan, Cemstone Concrete Placing Foreman on the Skyscape site. “In the case of the parking facility, if the mix design varied at all and affected our production, one call to the engineering department solved the problem.”

With the first four floors completed, construction moved upward to the 150 by 150-foot decks, columns and walls. Adolphson & Peterson, after several months of touring job sites in Seattle, Chicago, and other high-profile projects across the nation, elected to take advantage of the remote placing capabilities supplied by the KVM 39 X detachable boom.

“Adolphson & Peterson has a long history in concrete construction,” says Beagan, recalling the contractor’s completion of the IDS tower, one of Minneapolis’ most prominent high-rises, and one of the earliest pumped skyscrapers in the late sixties. “They were one of the first to explore the benefits of pumping and placing equipment. Although they no longer have a concrete division of their own in the Midwest, they understand the time and labor savings that accompany this type of placing technology.”

Removed from its truck and mounted on a 52-foot tubular mast erected within the pre-engineered knockouts in the building’s floors, the 39-meter boom is able to supply 40,830 square feet of coverage from one position. “The boom provides more reach than we actually need on this particular project,” comments Beagan, “We can hit all of the corners with no problem.” Positioned in the middle of the structure, and secured in two floor frames, the height of the mast allows the supplier/pumper to pour two floors before using the tower crane to raise the mast and boom. The lifting process is simple, requiring the placing crew to pull a pin on the bottom floor frame, remove the wedges, lift and repin and wedge. As of mid-April, the contractor was averaging two pours a week and wrapping up on the eighth floor.

The KVM 39 X truck-mounted pump equipped with 2023-5 pump kit handles 6,000-pound mixes for decks and 8,000-pound mixes for columns and walls, supplying the boom through hard pipe positioned to avoid disruption of other subcontractors on the Skyscape site.

“The general contractor plans on having the model units open to the public prior to the occupation deadlines for the rest of the building,” says Beagan. “We accommodated carpentry and finish work on the floors below us by suspending the pipeline from the ceiling of the first floor, in an area that will eventually become a hallway.” According to Beagan, as Cemstone crews continue with their regimented pour schedule, the suspended pipeline will not get in the way of open houses or subcontractors.

According to Beagan, the boom will remain situated on the mast until the building is completed. A versatile fleet of Schwing truck-mounted concrete pumps allows Cemstone to assign their KVM 39 X with detachable boom to the site throughout the entire construction period, cutting down on crane time. An agreement with the general contractor would allow the boom to be reattached to the truck if pouring were suspended for a lengthy period. This process typically takes less than an hour to transform the separate placing boom to a truck-mounted unit.

Each Skyscape condo offers a patio, posing a challenge to the Cemstone Engineering Department and pouring crew. Unlike the rest of the deck, the patio sections will be exposed to the elements, requiring a different mix design. Again, Cemstone’s one-stop-shop equipment, personnel and experience came in handy.

“The transition between the deck and patio pours certainly has to be orchestrated, but it’s relatively seamless with engineering, the ready-mix plant and placing crew in such close communication,” says Beagan. Between the Cemstone quality control personnel on hand, the producer’s engineering department, a finely tuned dispatch department and their batch plant’s ability to adjust mix designs on the fly, the 39 X remains supplied with the right mix at the right time to stay productive and meet job specifications.

In addition to the mounting system used on the Skyscape site, Cemstone has utilized alternative systems for their 39X placing boom, including lattice tower mounting for a recently completed art museum. Other Schwing mounting options include wall truss, ballasted cross frame, foundation frame and zero elevation frame on climbing forms.

“It’s a real pleasure to have a unified effort on a project like this,” according to Beagan. The effortless progress of Skyscape is testimony to good communications, a good crew and good equipment.