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April 17, 2008
FOR IMMEDIATE RELEASE
CONTACT: Phil Sneiderman
Steel Floors from Buckling
Undergraduate Develops Computer Model
to Test Designs and Prevent a Collapse
A Johns Hopkins undergraduate has developed sophisticated computer predictions to help structural engineers design sturdier and more cost-effective cold- formed steel floors and walls in low-rise buildings. With support from a university research grant for undergraduates, Ying Guan, a senior civil engineering major, performed tests and devised computer models that allow a building designer to test different materials and connections between thin- walled steel beams and columns and the wood panels or drywall used to support them.
"This is research that has a nice practical value to
it," said Ben Schafer, a Johns Hopkins associate professor
of civil engineering
who served as Guan's faculty sponsor. "The goal is to
eliminate at least one way that a cold-formed steel floor
design can fail."
Photo by Will Kirk
Guan's work will be among 45 Johns Hopkins student projects that will be honored today during the 15th annual Provost's Undergraduate Research Awards ceremony, hosted by Kristina Johnson, university provost and senior vice president for academic affairs.
Cold-formed steel is a building material that has
become increasingly popular over the last decade,
particularly in low-rise structures such as office
buildings. It can be a cheaper and more versatile
alternative to the more well-known hot-rolled steel, which
is cast from molten metal and rolled "hot" into a pre-set
shape before it is cooled. Cold-formed steel, on the other
hand, is created by bending thin sheets of steel into a
customized cross-section without heating. A cold-formed
steel beam, called a joist, can take the place of a
traditional wooden supports beneath a floor. To keep the
cold-formed steel joists from twisting or buckling, the
plywood or other sheathing material attached to the joist
must support them. Determining exactly how that support
works in real floor systems has been the focus of Guan's
Photo by Will Kirk
To design such floors in the safest and most cost- efficient way, structural engineers need to know more about when and why the connections between the steel beams and the sheathing materials will give way. To find out, Schafer last year enlisted Guan and another undergraduate to help him perform buckling tests on such beams in a campus lab. The experiments yielded data that led to new North American design specifications for cold-formed steel structural members.
To expand on this work, Guan applied for a Provost's Undergraduate Research Awards grant, which enabled him to devote time last fall to developing a computer model that can perform similar and more elaborate experiments digitally. "I created a computational model from scratch that would let us replicate these lab tests using numerical analyses and computer simulations," Guan said. "We are now able to test scenarios we haven't tested in the lab. We can change the type of wood or drywall and the way it's fastened to the cold-formed steel beams. We can change the type of fasteners that we use and the spacing between them."
Before any construction takes places, the program can give a structural engineer a better idea of what arrangements of materials and connections will be most resistant to buckling while supporting a floor that stands up to heavy furnishings and foot traffic, the student said.
Undergraduate Ying Guan, right, conducted
tests on cold-formed steel beams in this structural
engineering lab at The Johns Hopkins University. His
research was supervised by Ben Schafer, an associate
professor of civil engineering.
Photo by Will Kirk
Guan's work on the lab tests and the computer models will be incorporated into future design standards and be included in two scientific papers that will be presented later this year at international conferences on cold-formed steel structures, Schafer said. The work also will become part of a peer-reviewed journal article that Schafer's team is preparing. Guan will be listed as a co-author on three of these papers.
"That's the primary reason I came to Johns Hopkins, because of the undergraduate research opportunities," said Guan, who is from the Baltimore suburb of Parkville, Md., and is a graduate of nearby Perry Hall High School. Johns Hopkins' relatively small civil engineering program has enabled him to have greater access to his professors and more interaction with his classmates, Guan said. He is now applying to graduate schools to pursue a doctorate in structural engineering.
"As a kid, I was always mesmerized by the tall buildings in New York and the magnificent bridges in California," Guan said. "But I wanted to go beyond simple sight-seeing and admiration. I wanted to understand how these structures worked."
Schafer said he enjoys getting creative undergraduates like Guan involved in research projects that allow them to help solve some of the mysteries of structural engineering. "It's awesome to watch students who don't realize how much they don't know yet," he said. "They don't limit their thinking. They have a lot of fresh ideas, and that's what I'm looking for."
Since 1993, about 40 Johns Hopkins students each year have received Provost's Undergraduate Research Awards grants of up to $3,000 to conduct original research. Some have published their results in professional journals or presented them at scientific conferences. The awards, funded through a donation from the Hodson Trust, are an important part of the university's mission and its commitment to provide research opportunities for undergraduates. The awards are open to students in each of the university's four schools with full-time undergraduates: the Krieger School of Arts and Sciences, the Whiting School of Engineering, the Peabody Conservatory and the School of Nursing.
Color images of Ying Guan and Ben Schafer available; contact Phil Sneiderman.