Professor seeks to improve steel structures via geometrical cutouts that better absorb loads
While working as a structural engineer in California, Matthew Eatherton saw myriad ways the steel industry could break from century-old methods and delve into the then-burgeoning fields of subtractive and additive manufacturing – the later commonly referred to as 3-D printing – and improve building performance.
Now an assistant professor with Virginia Tech’s Charles E. Via Jr. Department of Civil and Environmental Engineering, Eatherton will be using a five-year, $500,000 National Science Foundation CAREER Award to research how steel plates with carefully designed geometric patterns – or voids -- cut into them can better withstand everyday loads and extreme events – high winds, blast or shock from an earthquake – than the standard solid steel plates currently used.
“We have a unique opportunity to advance the industry and improve performance,” Eatherton said of steel-framed buildings subjected to earthquakes and other hazards.
A Virginia Tech College of Engineering faculty member since 2010, Eatherton said advancements in water-jet and laser cutting technology in subtractive manufacturing, where material is removed from a structural component, and the growing use of 3-D printing in additive manufacturing, were “not being used to their potential in the steel industry.”
Steel buildings are designed to bend without fracturing, a property known as ductility, as they absorb extreme lateral loads from an earthquake or wind from a hurricane. Yet solid plates subjected to shear are prone to buckling and fracture, thus crumbling the flat, solid surface, and leading to the potential for great damage.
Eatherton’s solution is to “improve ductility and energy dissipation ability by strategically removing material from the plates rather than adding more material.” By introducing small cutouts – ring-shaped, butterfly-shaped, etc. -- global shear deformations in steel plates can be converted into smaller ductile mechanisms that resist buckling and increase stiffness within steel structures.
Investigation by Eatherton and his research team will include computational modeling and physical experiments, both in reduced-scale and then full-sized steel components at Virginia Tech’s Thomas M. Murray Structural Engineering Laboratory. As part of the CAREER Award, Eatherton will be able to fund two civil engineering doctoral students to work on the project, in addition to another doctoral student already working on the research.
Development of the design approaches will take years, possibly beyond the five years outlined in the NSF Award, to be incorporated in U.S. building codes. “You can never test enough configurations,” Eatherton said.
Eatherton, who worked as a structural engineer from 2001 until 2006 in earthquake-prone California, also has teamed with faculty within the Virginia Tech College of Architecture and Urban Studies to explore the use of exposed geometrically-cut steel plates in building interior designs to serve both structural purposes and architectural form in terms of screening and aesthetics.
The research work builds on an earlier grant associated with a faculty fellowship awarded by the American Institute of Steel Construction and also draws from Eatherton’s doctoral research at the University of Illinois at Urbana-Champaign, where he earned a doctorate in 2010. He earlier earned bachelor's and master’s degrees from the University of Missouri at Columbia in 1997 and 1999, respectively.