LONG-TIME FATIGUE PROPERTIES OF GRADE 60 REINFORCING STEEL
Design requirements to prevent fatigue fracture of reinforcing steel stated in the AASHTO Specifications for Highway Bridges are based on the mean fatigue limit at 5 million cycles. An experimental investigation was performed to determine long-time fatigue properties of Grade 60 reinforcing bars at stress ranges just below the fatigue limit at 5 million cycles. Fatigue tests were conducted on beam specimens containing reinforcing bars. Six bars from five U.S. manufacturers were evaluated. Each bar was embedded as main reinforcement in a concrete beam. Five bars were evaluated at target stress ranges of 2 ksi (13.8 MPa) below the mean fatigue limit at 5 million cycles. One bar was loaded at a target stress range of 4 ksi (27.6 MPa) below the mean fatigue limit. Bars in five specimens fractured due to fatigue. Failures occurred between 31 and 471 million cycles of repetitive loading. One bar survived over 1 billion cycles. It is concluded that at a stress range below the fatigue limit set in the AASHTO Specifications, straight reinforcing bars will survive the stress induced cycles during the service life of a highway bridge without fracture. Further research is needed to determine the fatigue properties of reinforcing bars at bends. Deflection measurements during fatigue loading showed creep under cyclid loading. (FHWA)
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Corporate Authors:
Construction Technology Laboratories, Inc.
5400 Old Orchard Road
Skokie, IL United States 60077-1030Federal Highway Administration
Office of Research, 1200 New Jersey Avenue, SE
Washington, DC United States 20590 -
Authors:
- Rabbat, B G
- Publication Date: 1983-1
Media Info
- Pagination: n.p.
Subject/Index Terms
- TRT Terms: Accelerated tests; Creep; Deflection; Dredging; Load tests; Reinforcing steel; Repeated loads; Stresses
- Uncontrolled Terms: Steel beams
- Subject Areas: Geotechnology; Highways; Marine Transportation; Materials; I34: Steels and Metals;
Filing Info
- Accession Number: 00372481
- Record Type: Publication
- Report/Paper Numbers: FHWA-RD-83-SO1263 Final Rpt., FCP 35L3-062
- Contract Numbers: DTFH61-81-C-00112
- Files: TRIS, USDOT
- Created Date: Jun 30 1983 12:00AM