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Cracking and Tension Stiffening Behavior of Corroded RC Members

Publication year Port and Airport Research Institute Report 046-02-01 2007.06
Author(s) Jianguo DAI,Ema KATO,Mitsuyasu IWANAMI,Hiroshi YOKOTA
Department
/Divison
Life Cycle Management Research Center for Coastal Infrastructures Project Researcher
Executive Summary

 This paper studied experimentally and analytically the tension stiffening and cracking behavior of corroded uni-axial RC members. Eighteen RC members of 2.0m in length were prepared for the experimental tests and thirteen of them had experienced different levels of impressed current deterioration. Test variables included rebar type, rebar diameter, and transverse confinement condition. The steel corrosion and cracking distributing properties, corrosion-induced bond loss, and the corrosion-induced tension stiffening deterioration were investigated in details. It was found through the tests that the localized deformations, namely the corrosion-induced cracks and it-affected loading cracks, are highly correlated with the un-uniformity of steel corrosion. Moreover, it was concluded that, compared to the losses of steel cross-section and effective concrete cover, the bond loss-induced tension stiffening deterioration may be not a critical factor responsible for the
global stiffness loss of corroded RC members.
 Further careful analysis based on a discrete modeling approach was performed to quantitatively clarify the relationship between the tension stiffening deterioration and the corrosion-induced bond loss. It was understood through the analysis that the corrosion-induced bond loss may not cause severe tension stiffening loss
except when the steel corrosion is extremely severe. The reason is that the tension stiffening reflects the coupled effects of many factors like the crack spacing, corrosion-induced reinforcement ratio loss, and the bond deterioration. This analytical finding coincided well with the experimental one. On the other hand,
analysis also showed visually that the increase of the localized crack width induced by the steel corrosion should be a major concern for the structural performance deterioration of the corroded RC members related to the serviceability.
 This research provides information useful for the appropriate evaluation of the remained serviceability of corrosion-deteriorated RC structures in practice.

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