Abstract
Pitting corrosion is one of the most common forms of localized corrosion. Corrosion pit results in a stress concentration and fatigue cracks usually initiate and propagate from these corrosion pits. Aging structures may fracture when the fatigue crack reaches a critical size. This paper experimentally simulates the effects of pitting morphologies on the static and fatigue behavior of steel bars. Four artificial notch shapes are considered: radial ellipse, axial ellipse, triangle and length-variable triangle. Each shape notch includes six sizes to simulate a variety of pitting corrosion morphologies. The stress-strain curves of steel bars with different notch shape and depth are obtained based on static tensile testing, and the stress concentration coefficients for various conditions are determined. It was determined that the triangular notch has the highest stress concentration coefficient, followed by length-variable triangle, radial ellipse and axial ellipse shaped notches. Subsequently, the effects of notch depth and notch aspect ratios on the fatigue life under three stress levels are investigated by fatigue testing, and the equations for stress range-fatigue life-notch depth are obtained. Several conclusions are drawn based on the proposed study. The established relationships provide an experimental reference for evaluating the fatigue life of concrete bridges.
Highlights
Corrosion reduces the effective cross-sectional area of steel bars employed in concrete structures and leads to the deterioration of their mechanical properties
The present paper aims to investigate the effect of pitting corrosion morphologies on the static and fatigue behaviors of steel bars
Note: The specimen number in the first column corresponds to the notch size
Summary
Corrosion reduces the effective cross-sectional area of steel bars employed in concrete structures and leads to the deterioration of their mechanical properties. Few studies focus on the mechanical properties of steel bars with different morphologies of pitting corrosion under static and fatigue loading conditions. Quantitative relationships for the yield strength and ultimate strength with respect to corrosion loss were obtained and some corresponding constitutive models were proposed [15,16,17]. Most of these studies focused on the static loading effect on mechanical behavior of steel bars, and an average corrosion rate was typically applied without considering the influence of corrosion pits. The present paper aims to investigate the effect of pitting corrosion morphologies on the static and fatigue behaviors of steel bars. Several conclusions are drawn based on the proposed study
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