Title: Fatigue Strength of Hot Rolled Deformed Reinforcing Bars

Author(s): James G. MacGregor, I. C. Jhamb and N. Nuttall

Publication: Journal Proceedings

Volume: 68

Issue: 3

Appears on pages(s): 169-179

Keywords: beams (supports);cyclic loads;deformed reinforcement;fatigue (materials);high strength steels;reinforced concrete;reinforcing steels;research;tensile strength.

DOI: 10.14359/11303

Date: 3/1/1971

Abstract:
This paper reports fatigue tests on #5, 8, and 10 reinforcing bars (16, 25, and 32 mm diameter, respectively) with nominal yiels strengths of 40, 60 and 75 ksi (2800, 4200 and 5300 kgf/cm^2). Tests were carried out on reinforced concrete beams containing one such bar and on specimens machined from the bars. Although the fatigue strength of the machined specimens varied directly as the ultimate tensile strength of the bars, the fatigue strengths of the bars themselves were essentially consistant and equal to 30 ksi (2100 kgf/cm^2) for a zero to maximum tension cycle. This paper suggests that this may be caused by the decarburized outer surface of the bars and stress concentrations at the base of the deformations.