It’s a Race to the Top with Unique Placing System On Indianapolis Luxury Hotel
R.L. McCoy, Inc., Columbia City, IN are completing one deck every week on the new 23-story Conrad Indianapolis & Residences, a five-star hotel and condominium complex by Hilton Hotel’s luxury division. Located in the heart of downtown Indianapolis, the new building will feature grade-level retail and 243 luxury hotel rooms topped by 18 residential condominiums. With an occupancy deadline of Spring 2006, contractors have utilized a unique combination of a self-climbing form system and truck-mounted concrete pump with detachable boom manufactured by Schwing America. A fast setting, chemically charged mix design is also helping to keep the project on schedule.
Joint venture developer Circle Block Partners, LLC and general contractor Hunt Construction Group, Inc., with dual headquarters in Phoenix and Indianapolis, broke ground on the cast-in-place post-tensioned structure in April of 2004. Concrete contractor Bowen Engineering Corporation, Indianapolis, oversees cost-effectiveness and efficiency of concrete operations.
Concrete pumping contractor R.L. McCoy has been on the site since September 2004, beginning with multiple spread footing pours. Gary Brown, manager of McCoy’s Indianapolis office, commented on the challenges involved with pump set up in the busy downtown area.
“Buildings on the north and west side of the property eliminated those areas for pump set up. On the south and east, there are major traffic arteries, not exactly forgiving for ready mix access and our equipment. Shoring also hindered our set up room,” he said.
The general contractor managed to develop a pour schedule to accommodate the supply trucks and pumper, closing down one-half of a traffic lane on the east side of the project at 9:00 AM on weekdays following rush hour. This allowed R.L. McCoy to utilize sidewalk space and the extra room to set up the pump. “With that system, we were still forced into only 20 to 22 feet of set up area,” says Brown.
Depending on the day’s specs, Brown says R.L. McCoy utilized just about every long boom in their fleet. “Every boom pump from 32 to 42 meters was on that site at some point,” he said. Average individual pours ranged between 300 and 500 yards, and crews placed an estimated total 2,000 yards upon completion of the foundation.
According to Brown, the company’s Schwing KVM 39 X made the grade as the most useful pump during the initial days of construction, providing the small foot print and long boom reach important to this particular project. “The 39-meter boom pump has a lot of boom for the amount of set up space it requires,” says Brown. “It got us through a few rough days in the beginning before the shoring came down.”
With 127 feet of vertical reach and over 105 feet of horizontal reach, the 39-meter boom pump reached into the corners of the foundation from its cramped quarters.
With the foundation completed and shoring dismantled, McCoy brought in their Schwing KVM 52 with Overhead Roll and Fold boom to complete deck pours on the hotel’s first six floors. This boom design allows the first section to be angled away from the pour and the remaining three sections to be inserted easily deep into pour zones. With 170 feet of vertical and over 157 feet of horizontal reach, McCoy’s KVM 52 completed the structure’s first six floors from an easily accessible set up area. To maximize production on the remaining 17 floors of post-tensioned flat deck pours, the general contractors elected to utilize a separate placing boom. McCoy stepped up with their 32 XL truck-mounted pump with detachable placing boom. The boom was mounted on a zero-elevation cross frame, mounted directly on top of the core formwork system. The transfer of the boom from the truck to the forms takes less than one hour. The formwork features built-in hydraulic jacking cylinders, creating a self-climbing system for the placing boom.
Forming Concepts, Inc, Gilberts, IL, the manufacturer of the forming system, is a pioneer in the attachment of placing booms to self-climbing systems. “Contractor customers of ours say it is the only way to go,“ reports Forming Concepts Executive vice-president Norton Baum. The company’s Tru-Lift system being used in Indianapolis features large single-stroke hydraulic cylinders to jack the formwork, boom and even a lift of rebar. “We are all about making it easy for the contractor to attach a boom to our forms,” Baum adds, “A placing boom adds tremendous loads to the form system, but our design transmits those loads to our supports. We think it is a selling point that we can do this.”
Using a 400-foot supply line, the 32 XL truck pump pushes a tough mix to its 32-meter counterpart, completing one floor deck every week, an estimated 350 yards of concrete. Two pours are necessary for each deck – one smaller, approximately 130-yard pour requiring a little over two hours of operator and equipment time, and a larger, approximately 220-yard pour requiring three hours. According to Brown, a very “high chemical,” 5070 psi mix is responsible for the less than ideal production figures.
“The mix is chock full of accelerants. It’s incredibly fast-setting, and in that respect, it has a very short shelf life,” says Brown. This forces Chicago-based ready-mix supplier Prairie Material, placers and finishers to move quickly.
“I’ve never seen a mix design work like this,” says Brown. “Some of the decks are about 70 feet wide. Almost immediately following our pours, they’re applying power trowels. And within 15 hours of placement, the mix is already 80 to 85 percent set – enough to allow them to begin pulling cable.”
R.L. McCoy crews switched to the piston side of the pump at the 15th floor to efficiently move the mix at lower pressures and still achieve the output required by the contractor. “This is a challenging mix to pump – I wouldn’t allow anything potentially dangerous into this hopper. But there’s no doubt in my mind this pump is earning its keep.”
Equipped with a 2023-5 Generation III pump kit, the 32 XL truck pump features maximum output of 209 yards per hour. It easily handles mixes containing up to 2.5-inch aggregate. The machine’s Rock Valve™ provides excellent feeding of the material cylinders – important when pumping harsh or low slump mixes. “The water to cement ratio isn’t exactly ideal for these pumps, but they rip through it just fine,” says Brown.
Upon completion of a deck, Brown estimates it takes the site’s carpenters approximately four hours to jack the forms and placing boom for the next pour. Meanwhile, McCoy’s crews add the appropriate amount of line system to reach the boom’s new location.
The top five floors of the 287-foot high structure are dedicated to 18 residential condominiums, some covering two stories of the building. To accommodate the change in floor plan, the substructure of floors 18 to 23 consist of post-tensioned flat decks and beam and girder systems. Extra space requires extra concrete, and each deck above the 17th floor requires between 420 to 475 yards of the fast-setting mix. Utilizing the same truck-supplied detachable 32-meter boom, contractors once again executed two pours per deck, placing an estimated 90 yards every hour. R.L. McCoy completed deck pours on the 18th floor in April. Contractors estimate concrete placement on the Conrad Indianapolis & Residences should wrap up in May.
At the completion of the project, R.L.McCoy’s Schwing 32XL truck pump will be reunited with its placing boom and begin servicing the Indianapolis area as a versatile tool for residential and commercial concrete placement.