While customer demand is currently the biggest factor motivating precasters to adopt BIM, producers such as Coreslab are part of a growing group that recognize its benefits. Read More
When sophomores at Valparaiso University in Indiana enter their new, all-suite residence hall this fall, they will appreciate the spacious floorplans, kitchenettes, and air conditioning. But what’s behind the scenes is even more impressive. The 85,000-square-foot structure is the university’s first dormitory to be built entirely with precast concrete. In fact, the 300 students would not be moving into their new rooms so soon if not for its precast design, executed with building information modeling (BIM).
After securing the project bid, the Chicago office of Minneapolis-based Mortenson Construction chose its materials to meet the aggressive 12-month timeline. “We knew that by using structural and architectural precast, we could meet the deadline with fewer jobsite quality issues,” says Andy Frank, construction executive for Mortenson. After successfully partnering on the KFC Yum! Center arena in Louisville, Ky., Mortenson selected Coreslab Structures Inc. of Indianapolis as the project’s precast producer.
“Once we get a job and see the client’s model, we can quickly determine how the precast design integrates with mechanical, electrical, and plumbing, and easily change our framing plan based on potential conflicts,” says Corey Greika, Coreslab’s Indianapolis precast sales manager and vice president. “We received Mortenson’s model of the Valparaiso project before we started our engineering, so we could punch it into our structural analysis program and start cranking out numbers without having to lay out the building first. It saved us days of creating and revising drawings.”
Mortenson was an early adopter of BIM technology in 2005, when the contractor began using the tool as part of its virtual design and construction approach. The company now uses it for every project, about one-quarter of which involve precast concrete. “We work hand-in-hand with architects and precast producers very early in the design process to make sure the structural requirements fit with the aesthetic design,” says Frank. “Rework is easily cut in half because the work is so much more accurate when all the trades are coordinated.”
At Valparaiso University, the planning process took about two months upfront, with several design iterations to satisfy both the structural and aesthetic concerns. “Speed is the main benefit of using BIM,” says Greika. “The 3D model educates each partner when they come on to the project so they know what limitations already exist and can make decisions more easily. No one is operating in a vacuum.”
Jobsite payoff
The Valparaiso residence hall had its share of design challenges that were made bearable by BIM. Rather than a 90-degree L shape, the building’s footprint angles to resemble a number seven. Coreslab planned the architectural brick-inlay panels by “walking around” the building in the 3D model. “We have to lay out the brick coursing around all the windows and doors ahead of time,” says Greika. “With a model, we can literally see how it’s going to line up when we turn a corner.”
Using precast panels instead of a brick and mortar façade proved to be a wise decision, as the region’s unusually harsh winter would have prevented onsite bricklaying for weeks, if not months.
Structurally, the producer helped resolve HVAC conflicts and planned the locations of shear walls around the building’s openings to handle the specific weight requirements of precast elements. The process was made more challenging by the contractor’s plan to install prefabricated bathroom units after the structural elements were erected. “A precast structure is generally more closed than a poured-in-place building with concrete columns,” says Frank. “But here, we left openings large enough to slide whole bathrooms from one side of the floor to the other.”
Frank estimates the project’s precast design, combined with BIM and a design-build approach, shaved two to three months from the project timeline. With frequent conference calls to ensure seamless coordination, the designer, contractor, and subcontractors virtually eliminated budget issues and change orders. “In a non-design-build scenario, all the stars might not have aligned as well,” he says, “but we had the right team with the right delivery method to get it done.”
