M. Prieto, P. Tanner, C. Andrade
Corrosion can affect bond between reinforcing bars and concrete and with it the transfer of longitudinal stresses between both materials. Loss of bond is normally characterized by brittle behaviour thus it should be analysed within the framework of the assessment of damaged structures in order to avoid it. Factors that affect bond strength include the weakening of the steel bar confinement due to cracking of the concrete cover and/or stirrup corrosion, development of corrosion products at the interface, and, in the case of ribbed bars, reduction of the relative rib area due to cross-section loss in the steel. A number of experimental studies have been conducted in recent years on bond failure, the findings have diverged rather widely, however, due primarily to differing test conditions.
In an attempt to surmount the inconsistencies in bond prediction with corroded steel bars, eccentric pull-out tests were carried out with specimens subjected to both accelerated and natural corrosion [1]. In this study a semi-empirical formulation accounting for both pull-out and splitting failures is proposed to assess bond of corroded and non-corroded steel bars. This formulation is obtained by means of multiple linear regression analysis of a database of more than 650 tests of corroded and non-corroded bond tests, including the tests performed in [1]. The database used includes a wide range of influencing variables regarding to bond, such as bar diameter, concrete strength, concrete cover, anchorage length, confinement ratio and cross-section loss due to corrosion. Several statistical criteria have been used to analyse the proposed formulation and the influence of the explanatory variables. Also a comparison with several formulations found in literature, including the proposal of Fib Model Code 2010 for corroded bars is performed. The proposed formulation could be used in the structural assessment of corroded reinforced concrete beams.
Published on 01/01/2014
DOI: 10.2749/222137814814027981Licence: CC BY-NC-SA license
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