CHICAGO Hollow structural sections (HSS) are gaining ground in industrial applications that previously favored wide-flange beams, but the steel tube product still faces challenges as engineers familiar with other materials are slow to substitute.
HSS is gaining traction in Latin America and other regions where seismic standards are paramount, participants in a roundtable discussion said March 21 at the Steel Tube Institutes Inaugural HSS Market Conference in Chicago. It also is gaining support from engineers looking for specific attributes.
"It depends on what architects are looking for. Curves seem to be in," one engineer said. "We understand wide-flange beam connection detailing better than HSS, but we like HSS for columns, including exposed applications."
Others are using HSS inside masonry and in exposed applications. "Its easy to wrap masonry around it," according to Allan Ortega-Gutierrez, structural engineer at Tucson, Ariz.-based M3 Engineering & Technology Corp.
But HSS is also encountering some major limitations, participants said.
One hurdle for HSS is the conservative nature of some engineering companies that dont want to try something new. "I know 8-inch standard pipe. I dont have to check (further)," Matthew G. Brown, applications engineer at Foothill Ranch, Calif.-based Risa Technologies LLC, said to illustrate a common mind-set among industry members.
Another hurdle is that some structural steel fabricators prefer beams because they believe they are able to preserve their margins better working with the same suppliers over years. Others said engineering companies tend to rely too much on what their fabricators tell them, giving them little incentive to seek out new productslike HSSthemselves.
Several engineers acknowledged they havent always gone the extra mile to see if other materials might work than those previously used or to make new demands on their fabricators capabilities.
"(Some) engineers rely on the fabricator as the be-all, end-all in procurement and can be biased based on costs and margins," according to Tabitha Stine, director of technical marketing at the Chicago-based American Institute of Steel Construction. "There is steel around at all these warehouses," she said, "but Jim at the fabricator is counted on as the expert."
Some engineers noted challenges sourcing HSS. While thats not an issue in North America or Europe, where HSS is used more extensively, it is scarce in other regions, especially larger-diameter round tubing, they said.
Even so, some regions are seeing a shift. In Canada, builders are using wide-flange beams "less automatically just because it is cheaper," Chris Jacques, structural engineer at Read Jones Christoffersen Ltd. (RJC), Vancouver, British Columbia, said, adding that builders have learned money can be saved elsewhere when using HSS.