Earlier this year in the Arizona desert between Loop 101 and Pima Road on the Salt River Pima Indian Community near Scottsdale, construction crews poured and lifted the heaviest tilt-up panels ever erected in the U.S. to create a mostly indoor water park resort for Great Wolf Lodge.
The heaviest panel placed was 369,000 lb, or about 183 tons, according to the Tilt-Up Concrete Association. The previous record was set at Ocean Center in Daytona Beach, Fla., in 2009 with a panel lift of 339,000 lb, or 170 tons.
“Having people do it on the ground, you get better quality, and it is much safer than cast-in-place,” says Brad Hughes, project manager, Mortenson Construction, the general contractor. Many of the nearly 20 other Great Wolf Lodges were built with cast-in-place walls for their water parks, he says.
In Scottsdale, the tilt-up panels surround the 85,000-sq-ft indoor water area. The integrated 27,000-sq-ft family entertainment center is constructed of structural steel, and the 350-room, six-story hotel is cast-in-place concrete. The envelope in the family entertainment center and the hotel is made of wood and architectural elements and mostly prefabricated EIFS panels.
The architect for the project is the Los Angeles office of Gensler. Concrete work, including tilt-up panel fabrication and erection, was performed by Suntec Concrete.
Israel Sanchez, lift engineer, Suntec Concrete, says the extreme length and weight of the largest of the panels created concerns among the team about deflection as the lift progressed. The largest of the 183-ton panels was about 70 ft tall and 63 ft wide.
To overcome those issues, Sanchez says the Suntec Concrete team used 7,000-psi concrete and several tons of steel for reinforcement. By comparison, typical concrete slabs used in residential and commercial construction are comprised of 3,000- to 4,000-psi concrete. The panels were slightly more than 7 in. thick. Even using more durable concrete and the over two dozen tons of reinforcing steel, the panels deflected substantially during erection, as the team anticipated, but were not damaged, he says.
The Suntec Concrete and Mortenson team used a Manitowoc 300-ton crawler crane to lift the 58 panels, four of them weighing 183 tons. The total average lift weight per pick, including supporting rigging and other accessories, was nearly 220 tons, Sanchez says. A special spreader bar was built specifically for the project to handle the width and weight of the largest panels, he says.
The rigging for the crane was primarily 9-in. steel cable, attached to eight different pick points when panels were poured on the ground, Sanchez says.
The panels were attached to each other after erection using NMB splice-sleeves, or grouted mechanical splicing connectors. The system uses a cylindrical steel sleeve filled with a portland-cement based, non-shrink, high early strength grout. Reinforcing bars that are inserted into a sleeve meet near the center, then the interior is filled with SS Mortar grout.
North Woods in the Desert
Tom Sze, entertainment leader, Gensler, says the theme behind Great Wolf Lodge is rooted in the story of cartoon characters Tooth & Nail, The Beaver Brothers. Gensler uses the characters to provide guests an immersive experience that gives a theme park feel to the venue.
The interior includes a high level of interior wood finishes. Wood is used for more than just for accents, however. Among the wood elements that create the resort’s atmosphere are 4-in. structural tongue-and-groove decking used as part of the roof and waterproofing system.
In the water park, the roof structure consists of glulam trusses, structural tongue-and-groove decking, a Grace ice and water shield, plywood, insulation and then a Carlisle waterproofing membrane with a Berridge Cee-Lock standing-seam metal roof, Hughes says.
“Wood is also used because of the humidity in there. There are some steel elements,” Hughes says, adding that the first barrier is designed to keep humidity inside the water park and the second is to keep rain and other natural elements outside the facility.
While Mortenson and its subcontractors built the shell for the water park area and the hotel, nearly all of the water park features and support systems are being built by Neuman Pools of Beaver Dam, Wis. The pool company performs all of its own concrete work as well as the proprietary HVAC and water systems. Like Gensler, Neuman Pools has worked on all Great Wolf Lodges built across the nation.
“We design it with them, and they do a great job,” Sze says.
The facility is expected to open to guests in September.