Wally Prebis knows as much about structural concrete as one person can.
Prebis has spent his entire career, 41 years, telling anyone who would listen that prestress concrete is one of the best building materials around and why it should become a staple of the construction industry.
Now, Prebis, 79, who founded and led the Colorado Prestressers Association as its executive director for four decades, retired from the job this fall, and his calm, confident voice will be sorely missed. As the CPA leader, he convinced an entire industry, from owners to code officials and contractors, that prestress concrete isn’t cumbersome, dangerous or expensive—and that it can be exactly the right material for many jobs.
And people listened. In the 1960s, Denver had few prestress buildings. Today, structures built using prestress concrete are everywhere, from parking garages to freeway overpasses, industrial buildings and schools.
For his tireless work in convincing an industry to explore the many applications of prestress concrete, and the thousands of hours he spent teaching college students and engineers how prestress works, Mountain States Construction magazine is honoring Prebis with its annual Legacy Award, given to an individual who has made significant contributions to the local construction industry and the community.
“It’s been fun, and it just seemed to get more interesting as I went along,” Prebis says. “I helped create the CPA in 1969, and it has been my professional passion ever since. My favorite part has been educating students about the value of reinforced concrete and how it works. I hope I’ve made a difference.”
He has. To hear his colleagues tell the story, if not for Prebis, the prestress concrete industry in Colorado would be well behind where it is now. “Without Wally, it would be a fraction of what it is today,” says Kevin O’Connell, who works in sales for Rocky Mountain Prestress, Denver. “We’d still be on the sidelines without his hard work.”
What Prebis did early in his career was no less than save prestress from an early death. Double tees were being used in Denver as load-bearing wall members until 1969 when the city of Denver’s building department questioned how the walls were being designed.
“At that point in time, prestress concrete was still in its infancy,” Prebis says, “so there was no prescribed design procedure for this kind of double tee use, and Denver had no choice but to ban further construction for that kind of structure.”
Clearly, Colorado prestress producers had a problem. Enter Prebis, who presented new data to city officials based on the fire testing of double tees he had witnessed in an Illinois lab. A double tee was placed horizontally in a furnace and subjected to flame to establish a fire rating. Force from hydraulic jacks was applied at the ends of the tee to hold the test member in place.
The expansion force was recorded and used to develop a design for a load-bearing double tee wall. The data was solid, and at Prebis’ urging, the city removed the ban and the prestress industry took off, with the CPA and its two members, Stresscon and Rocky Mountain Prestress, at the helm.
“Wally became a nationally recognized expert in fire-resistant concrete construction,” says J.D. Schafer, a project manager for Stresscon for 24 years. “He became a familiar face to building officials around town. They trusted him, and his credibility gave our industry a big boost. They knew he’d have the right answers to their questions.”
O’Connell also points to Prebis’ ongoing efforts to standardize prestress construction and educate people how to make the best use of it. “With Wally’s help, Colorado and the Denver metro area would be considered the most advanced precast markets in the United States now,” he says.
Prebis, who now divides his time between Denver and a home in Arizona, says he will continue to teach workshops and short courses in concrete construction at local colleges, something he has done for decades.
“Prestress concrete is now part of the standard curriculum in most engineering schools,” he says. “But it didn’t used to be that way, and I will try to do what I’ve always done—make sure students understand how important prestress is to constructing good buildings. It’s all over the place now, and that’s only going to grow in the future.”
Wally Prebis, 79
CPA Executive Director (retired)
Years in current position: 41
Education: B.S. in civil engineering, Colorado College
Family: Wife Lona (39 years) and three grown children, Kevin, Bob and Debbie; two grandchildren, one great-granddaughter