Newmark Structural Engineering Laboratory

Department of Civil and Environmental Engineering

College of Engineering

University of Illinois at Urbana-Champaign

Recent and Past Projects
NSEL Reports Series

Tension-Tension Fatigue Testing of Reinforcing Steel Bars


Principal Investigator: Gregory Banas

Research Assistant: Adrianne Wheeler

Wiss, Janney, Elstner Associates, Inc. (WJE) worked with NSEL on tension-tension fatigue testing of reinforcing steel bars. The objective of this testing program was to determine whether a set of 5 reinforcing bars sustain 5 million cycles under the stress range of 200 MPa at the stress ratio of 2. Twelve mm, 16 mm, and 25 mm size reinforcing bars were tested. If no failure occured in any of the five bars after 5 million cycles, then the test passed.

The procedure for testing was based upon the British and Brazilian Standards for fatigue tests on reinforced steel. In order to prevent tested bars from breaking at the grip section, each test specimen was prepared by securing 5 half-inch pieces of aluminum tubing to each end of the bar with Wood’s metal. The specimen was then strain gauged in order to take into account the amount of bending stresses the bar could receive during testing. Specimens were tested using a 50 kip MTS testing frame.

If you are interested in this project or if you have any questions, please contact Gregory Banas at
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