Preinsulated precast concrete paves the way for a dramatic finish.
By J.T. Long
In the race to finish the Eastland-Fairfield Career and Technical School Auto Academy before the school year started, innovative precast concrete panels smoothed the way. By building the 9-inch-thick, preinsulated, high-performance panels off site complete with finished surfaces inside and out, the suburban Groveport, Ohio, school district kept construction inconveniences to a minimum while maximizing visual interest. Outside, a pair of checkerboard flags and a winner’s circle embossed into the concrete entryway patio brought a NASCAR feel at a fraction of the price of custom brickwork. Inside, the 28-foot-high shell made room for 24 vehicle lift bays, two full-size paint booths, classroom and laboratory space complete with laser technology and computer diagnostics.
Laying the groundwork
The road to completion started as a team effort to fine-tune the plans. After one false start, a winning design incorporated ideas suggested at community meetings along with input from students. Administrators toured other precast concrete projects and saw the functional benefits.
“The sheer size of the building required large panels,” explains Dr. Mark Weedy, superintendent of Eastland-Fairfield Career and Technical Schools. “Plus, the extreme Ohio temperatures made the panel and joint structures appealing because they could expand and contract without cracking like brick and mortar construction.”
The 28,900-square-foot freestanding building includes 95 precast concrete wall panels ranging from 10-by-20-foot rectangles to massive 10-by-30-foot panels. Each panel includes 2 inches of rigid insulation sandwiched between 4-inch interior precast panels and 3-inch exterior precast panels. The design company, TRIAD Architects Ltd. of Columbus, Ohio, worked closely with the precast manufacturer, High Concrete Group, to balance the practical limitations of price, shipping size and load-bearing ability. “The sweet spot ended up being at the maximum size that would still fit on a standard tractor trailer,” says Steve Smith, TRIAD Architects project manager.
The result is an insulated wall that doubles as the structural exterior wall for the steel roof joists, eliminating the need for a steel perimeter frame. Because no vertical columns held the building together, temporary shoring supported the walls until the roof could be tied into place. “It was a matter of careful sequencing,” recalls Peter Macrae, TRIAD Architects president.
One of the biggest challenges was a pair of curved 10- by-12-foot keystone slabs above the glass doors that had to be dropped into place by a crane and welded. “It had to fit precisely, because it was the only thing tying the wall together laterally,” Macrae says.
The TRIAD design also called for two giant black-and-white checkered precast finish line flags on the front of the building above the large glass garage doors. The glass doors spill light onto the 20-foot black and white checkered stained concrete “winners circle” on the concrete floor in the front of the building. High Concrete
Group used a retarding agent to expose 6-foot square black and white relief patterns. In the final stages of production, High Concrete Group acid washed the entire building to create a smooth, clean finish. The use of three different materials (gray, black and snow-white rock) added about $5,000 to the entire project cost and required a meticulous attention to detail to avoid overruns on reveals, according to Josh Fisher, High Concrete Group project manager. However, it had a dramatic impact.
“It is aesthetically unique,” says Fisher. “It is amazing how many different possibilities there are for precast.”
High speed
Time was the other benefit of precast concrete for the functioning campus. Most of the work was done off site at High Concrete Group’s climate-controlled plant in Springboro, Ohio. That eliminated four to five months of teams of bricklayers on site and the need for a staging area on the functioning campus. It also eliminated rain delays, a major factor in Ohio.
“While the material cost of this option may be a little more expensive than the traditional brick and block cavity wall construction, the true savings lies in the erection time reduction and its impact on the job schedule,” says Macrae. He estimated that the district realized a 20 percent cost savings on the $4.6 million building in labor due to time schedule savings.
The job started with schematic designs in July 2006 and the district awarded the bid to Westerville, Ohio-based contractor Corna/Kokosing Construction Co. in March 2007. At that point, the contractor sat down with the architect, electricians and HVAC team to go over the details of embedding the wiring in the walls. “Coordinating this at the beginning saved a lot of problems later,” says Jamie Srbljan, Corna/Kokosing project manager. High Concrete Group started precast manufacturing in June 2007. By September 2007, they were ready to be shipped and erection was complete in a matter of weeks. The exterior was already finished. The interior just needed paint, because High Concrete Group used a gas powered trowel machine with an accelerated backup mix to ensure a smooth surface. Even the raceways for electrical and HVAC lines were already built into the walls.
The district took occupancy in March 2008 after bringing in the latest in automotive diagnostic equipment to give students a taste of real-world job skills. “The building took shape very fast,” Superintendent Weedy says. “We told the board to bring lawn chairs and watch it come together.”
“We are giddy about the final result,” says Jeff Hobbs, director of Business Affairs for Eastland-Fairfield Career and Technical Schools, the proud owner of one of the fastest-built, coolest-looking and highest-tech automotive training centers in the country. “We will definitely consider using precast concrete for future projects,” says Hobbs, whose district averages a new project every year.
J.T. Long, a freelance writer and editor living in Granite Bay, Calif. has written for numerous publications and magazines.
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