Modular construction with precast products offers reduced installation times and enhanced aesthetic appeal.
By Mason Nichols
Whether you’re a child stacking Legos to build an impenetrable fortress or a homeowner crafting a fire pit in the backyard, there’s something satisfying about creating a finished structure using individual components.
Beyond the fun, modular building continues to take the construction industry by storm. From healthcare to industrial buildings to multi-family homes and beyond, modular construction methods can benefit nearly any project.
But the true power of the approach is unlocked by selecting the right building material for the job.
Precast concrete products aren’t just durable and resilient. Precast components are quick to install, meeting and exceeding the needs of project owners. These attributes make precast a popular choice for modular building.
Standing strong in South Dakota
Wind is a powerful natural resource that can be harnessed to generate clean energy. Such is the case in eastern South Dakota, where the 14,000-acre Tatanka Wind Farm – the largest renewable-energy project in North and South Dakota – produces enough energy to power more than 60,000 homes.
Excessive wind can be a devastating force, impacting homes and businesses alike. With tornadoes a regular seasonal threat at the Tatanka Wind Farm, owners needed an on-site storm shelter with the ability to protect their team members during extreme weather events. The answer was precast concrete.
Minnesota-based Crest Precast Concrete partnered with local general contractor Huff Construction on the job. According to Brett Andrews, project manager for Huff Construction, the storm shelter was constructed for the wind farm’s operations and maintenance building.
“They were originally going to go with an interior design, but to maximize space inside their building, they shifted gears and went with a separate building for the precast concrete storm shelter,” he said. “This is a 3-acre site, so they decided to use some of their lay-down area for the shelter.”
Throughout the design phase, Crest Precast and Huff Construction collaborated closely to ensure the 20-person storm shelter was compliant with appropriate codes. Initially, the shelter was designed to adhere to the International Code Council’s ICC 500 standard. After client review, the team determined that the Federal Emergency Management Agency’s P-361 standard was more appropriate. With the new, more stringent standard in place and all partners on the same page, Crest Precast got to work manufacturing the shelter.
Kevin Thicke, drafting manager with Crest Precast, said the 48,000-pound shelter, which provides each person 5 square feet of space at max occupancy, is 16-feet tall by 8-feet, 6-inches wide. The shelter also boasts 56 weld plates between the floor, walls and roof.
“This storm shelter is a six-sided structure,” Thicke said. “We pour the individual panels, erect it in our yard and then ship it to the client in one piece.”
Because the shelter was preassembled at Crest Precast’s plant, installation time at Tatanka Wind Farm was reduced considerably. As Andrews said, the process was just about as simple as it could get.
“The only thing we had to provide Crest was a foundation for the structure to sit on,” Andrews said. “Beyond that, the shelter showed up on a lowboy, and we had a crane lined up. We picked it up with slings, put it in place and anchored it down.”
Installation was completed in just one day. Choosing precast gave the owners several advantages, including enhanced structural integrity, ease of assembly and heightened aesthetics. Andrews noted that because of the weight of the structure, less anchorage was required than if the shelter had been built with a competitive material, such as metal. Steve Mader, president of Crest Precast, also emphasized the shelter’s resilience.
“We trust our engineering completely,” he said. “When the engineer says to us, ‘This shelter will not slide, tip or flip in a major weather event with 250 mph winds,’ we’re confident if that day comes, there will be no issues.”
Simple solution in Swansea
Modular construction opens a world of possibilities for other structures as well, including utility buildings, classrooms and more. At the Boul Avenue Trailhead Park in Swansea, Ill., a modular precast solution was the material of choice for a combined restroom and storage unit. To manufacture the building, McCann Concrete Products of Illinois partnered with Easi-Set Worldwide, a Midland, Va.-based company, that licenses a variety of precast building designs to precast manufacturers throughout the industry.
The need for the combined structure was spurred by Swansea’s new bike trail, installed to provide additional transportation options for commuters and a safer means for students at the local High Mount School to access nearby sporting fields and subdivisions. McCann Concrete and Easi-Set met frequently to discuss the design as they identified the best possible approach.
“This particular building required a custom layout, which led us to some design and construction situations that we had not encountered before,” said Matt McCann, vice president at McCann Concrete. “But the Easi-Set team was able to pull knowledge and experience from a vast array of projects they’ve worked on around the U.S. and locally to help us find solutions that we may not have been able to find on our own.”
The team ultimately decided on a two-piece modular solution with a men’s and women’s restroom on one side and a storage unit with roll-up door on the other. The combined structure measures 16 feet high by 28 feet wide and weighs approximately 100,000 pounds.
According to Jeremy Smith, building products manager for Easi-Set, the process for installing the two modules on-site was straightforward thanks to the work accomplished ahead of time.
“Besides having the pad ready and stub-ups for the plumbing, essentially the building was ready to go once it arrived at the project site,” he said. “The water and sewer could be hooked up and ready to use on the same day as installation.”
The Easi-Set building does not require a separate footing for installation, as the post-tensioned floor slab functions in that role. McCann referenced this as a major advantage for precast concrete, noting that his crew was on-site for less than two days to fully install the building. He added that his team completes other operations prior to installation, also helping to accelerate the process.
“We don’t just cast the panels at our production facility – we assemble, apply coatings and install the fixtures,” McCann said. “We will even have electrical and plumbing inspections at our plant ahead of time to ensure that the building will be to code before it arrives on the job site.”
The structure in Swansea also features a split-face block design, giving it an attractive appearance that would not be attainable with other products.
Simple, flexible, powerful
As modular construction methods continue to gain popularity in the industry, more architects, engineers, contractors and project owners are turning to precast concrete solutions. With myriad advantages, including durability, resilience and ease of installation – along with the flexibility that enables it to be a part of nearly any imaginable project – precast is the ideal building material for embracing the modular approach.
Mason Nichols is a Grand Rapids, Mich.-based writer and editor who has covered the precast concrete industry since 2013.