Lehigh University
Lehigh University


Three ATLSS Center researchers honored by American Society of Civil Engineers

Richard Sause

Three researchers from Lehigh’s ATLSS Center have received an international award for their investigations into the performance of the diagonal braces that are used to help steel buildings better withstand earthquakes.

Richard Sause, James Ricles and Larry Fahnestock were recently awarded the 2009 Raymond C. Reese Research Prize from the American Society of Civil Engineers. ASCE, founded in 1852, is the oldest national engineering society in the U.S. Its membership includes more than 146,000 civil engineers worldwide.

Sause and Ricles are professors of structural engineering in the department of civil and environmental engineering at Lehigh. Fahnestock, who earned his Ph.D. in structural engineering from Lehigh in 2006, is an assistant professor in the department of civil and environmental engineering at the University of Illinois in Urbana-Champaign.

James Ricles

The three engineers were cited for their paper “Seismic Response and Performance of Buckling-Restrained Braced Frames,” which was published in September 2007 in ASCE’s Journal of Structural Engineering. They were credited by ASCE with developing “guidelines and recommendations that are directly useful to the engineering profession.”

Buckling-restrained diagonal braces, which were developed about 20 years ago in Japan, have in the past five years become the most widely used earthquake-resistant construction system in steel-framed buildings. These braces are designed to avoid buckling in compression under the large deformations that buildings undergo during earthquakes.

The Lehigh group conducted numerical simulations as well as physical tests to determine the extent to which such braces need to deform in tension and compression during earthquakes.

“The experimental testing we conducted was the first in which a complete buckling-restrained braced frame was erected in a lab,” said Ricles. “In previous projects, only individual braces or subassemblies had been tested. It’s important to test the complete system in order to account for the interaction effects of the braces and the other members of the frame.”

“We learned that the braces must to be able to deform more than the prevailing standards indicated,” said Sause. “That is, the demands placed on the braces were much greater than had previously been assumed in design practice.”

Larry Fahnestock

A buckling-restrained brace has a concrete-filled tube which encases the brace element to provide additional support and enable the braces to yield without buckling under compression.

The Lehigh research team developed criteria for evaluating and testing buckling-restrained braces and for ensuring that the tests confirm the braces’ performance and safety.

The research project lasted three years and was funded by the National Science Foundation (NSF) and the Pennsylvania Infrastructure Technology Alliance (PITA).

Sause is director of the ATLSS (Advanced Technology for Large Structural Systems) Center. Ricles is director of the ( George E. Brown Jr. Network for Earthquake Engineering Simulation) NEES program at Lehigh. Established and supported by NSF, the 15 member universities in NEES collaborate to provide research facilities for earthquake-engineering studies.

--Kurt Pfitzer

Posted on Tuesday, July 07, 2009

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