Development of a failure prediction method for grout filled damaged tubular members

Abstract

This paper presents the results of research regarding the existing failure prediction method and the development of an improved failure prediction method for grout filled damaged tubulars. The types of damaged addressed were localized denting of the wall, initial out-of-straightness, and residual stresses caused by the formation of the dent. The failure prediction method developed by Parsanejad accurately predicts the buckling capacity of small scale dent-damaged grouted tubulars. However, as the scale of the damaged tubulars approaches full scale, the Parsanejad method becomes overly conservative. An analytical method has been developed to predict the ultimate capacity of dent-damaged/grouted tubulars. The analytical method does not neglect the residual stresses caused by the formation of the dent. The analytical method more accurately predicts the ultimate capacity of the full scale dented/grouted tubulars than the Parsanejad method. The failure prediction method developed in this thesis has also been adapted to undented/ungrouted and undented/grouted tubulars. The failure prediction method developed in this thesis for dented/grouted tubulars produces buckling capacity values for full scale tubulars which are conservative by approximately 13.5%. The Parsanejad method underestimates the buckling capacity of the same tubulars by, on average, 22%. Although the failure prediction method developed in this thesis for dented/grouted tubulars is more accurate than the Parsanejad method, the method is more difficult to use than the Parsanejad method.