SAGINAW - The familiar wide flange structural steel beam hasn't changed much over the past century. It's the near-perfect combination of simplicity, strength and efficiency in structural building design.

So it's highly unusual in today's construction industry to see wide-flange steel with what appear to be holes in it, used in the structural support of a building. We found them during a walk-through of the expansion of Saginaw Valley State University's Pioneer Hall, where the unusual beams were holding up just fine, thank you.

" I haven't seen them used in my 40 years experience," said Joe Veryser, associate dean in the College of Architecture and Design and the university architect for Lawrence Technological University in Southfield. "Normally, they just cost more, and that's why people don't use them. But if they're using it in a Green building application, that could make sense. They're just going to pay a premium."

In fact, the expanded Pioneer Hall is being constructed under LEED guidelines - or Leadership in Energy and Environmental Design, a standard which offers varying levels of certification by the U.S. Green Building Council. LEED ratings are only given after a building is constructed - so the jury is still out on how the beams will help Pioneer Hall's rating.

Depending on the cut, they're called "castellated" (non-round hole) or "cellular" (round hole) beams, and the concept behind the design has been around since the early 1900s. The beams are particularly visible on old bridges, when structural weight was an issue, or perhaps when wartime demands made iron or raw materials scarce.

Castellated steel manufacturers are rare in the U.S. CMC Steel Group/ SMI Steel Products of Rockwall, Texas fabricated the cellular steel used at Pioneer Hall, and calls its product the "SmartBeam" design. They don't manufacture the steel by simply punching or cutting holes in the web of the beam.

Billy Milligan, vice president of CMC/SMI, wrote in Modern Steel Construction that prior to automated cutting and welding, castellated steel manufacturers used to split the beam apart, manually cut out the steel, then weld the beams back together. He wrote that the labor and expense involved in that process led to the abandonment of that type of processing - until 1999, when his company was able to automate the process.

SmartBeams, he wrote, are manufactured by cutting wide flange beams in a zig-zag pattern along the length of the web of the beam with a computer-controlled plasma torch. The two sections are then welded back together - which makes the beam taller by about 50 percent, and actually increases its strength by about 40 percent. Of course, the process also gives the beam the appearance of having holes or other shapes cut out of its center.

The beams are useful for long-span composite floor beams - the holes in the beams allow for easy flexibility in running mechanical systems. The long-span strength capabilities of castellated beams also make them well-suited for construction of multi-level parking decks, since they reduce the need for structural columns.

Don Allen, director of engineering for the Steel Framing Alliance, said he is aware of the use of castellated beams in parking decks, but their use in other types of construction has been slow to catch on.

He said strength, weight or convenience advantages that might be gained from the use of castellated beams are offset by their higher cost. And, their higher profile tends to raise floor to floor height.

"I have yet to see the use of castellated beams in an office building or a similar structure," he said.

In Michigan, he'd see them at Pioneer Hall. Paul Haselhuhn, an AIA architect on the project for Wigen, Tincknell and Meyer, said a number of factors went into the choice of the cellular beams. A reduction in structural steel weight by about 20 percent (vs. typical steel members) fit in with the LEED concept.

The steel, which has an interesting appearance, will be kept exposed and will fit aesthetically with the mechanical/engineering programs that will be housed within. Duct work and mechanical systems can be run through the beams, saving space, especially in the high-bay areas. The design of the addition/renovation allowed for straight beam lengths of more than 30 feet, which saves fabrication costs.

All in all, Haselhuhn said, the cost of the cellular beams are expected to be the about the same cost as traditional steel, or slightly more.

"In the end, the decision to use the cellular steel was a combination of things," he said. "Left exposed, it has some architectural value. It has practical value during the construction process and when the building will be occupied. Steel is definitely a green building product; it's about 90 percent recycled. For us, on this project, using this steel just made sense."

REFERRED TO AS "CELLULAR" beams (those without the round shape are "castellated"), the use of this type of structural iron is very rare in Michigan.