Some Recent Corrosion Embrittlement Failures of Prestressing Systems in the United States

Abstract

This paper is based on a paper presented by the authors at the FIP Symposium on Stress Corrosion Cracking of Prestressing Steel in Madrid, Spain, September, 1981. Having been asked to report on the incidence of embrittlement failures of prestressing steels in the United States in the recent past, the authors have highlighted this type of failure in this paper. Evidently, any failure of a prestressing steel tendon due to corrosion of any kind is undesirable. The need to exercise extreme care to protect prestressing steels in any application cannot be overemphasized. For the purposes of this paper, corrosion, or ordinary corrosion, is an electrochemical phenomenon in which the steel is affected by a particular environment, resulting in a measureable loss of metal. The failure of a given steel element occurs when the loss of material is so great that the remaining cross section is no longer capable of carrying the applied load. In failure, however, the metal generally still exhibits its normal ductility. On the other hand, stress corrosion cracking and hydrogen embrittlement are distinctly different manifestations of corrosion of prestressing steel, stressed generally to over 50 percent of its ultimate strength. Without attempting to