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Title: Aspects of the impact-echo method for the detection of voids within metal ducted post-tensioned bridge beams
Author: McHugh, John Paul
ISNI:       0000 0001 3624 7097
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 1999
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This thesis is concerned with the development of a non-destructive testing technique, namely the impact-echo method, for the evaluation of tendon ducts in post-tensioned prestressed concrete bridges. The impact-echo method has been shown to be useful for damage detection in concrete structures, particularly plate-like structures. However, when it is applied to beam-like rather than plate-like structures the resulting spectra are complex and difficult to interpret. One source of complications is the excitation of cross-sectional modes in the beam. This thesis discusses an investigation into the nature of these modes, and their potential applications for non-destructive testing. Finite element models have been developed to investigate cross-sectional modes where grouted and ungrouted ducts are present and the results from these are described together with an experimental validation. It is concluded that a shift in the frequency of the dominant cross-sectional mode can be used to identify large ungrouted ducts. In addition, the frequencies of the dominant cross-sectional modes can be predicted for both grouted and ungrouted cases using finite element modelling. Further finite element analysis showed that varying the compression wave speed in grout over a realistic range had minimal effect on the amplitude and frequency of the dominant cross-sectional mode.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TA Engineering (General). Civil engineering (General)