Acoustic Nondestructive Testing and Measurement of Tension for Steel Reinforcing Members
Abstract
Many concrete structures contain internal post-tensioned steel structural members that are subject to fracturing and corrosion. The major problem with conventional tension measurement techniques is that they use indirect and non-quantitative methods to determine whether there has been a loss of tension. This work developed an acoustics-based technology and method for making quantitative tension measurements of an embedded, tensioned steel member. The theory and model were verified in the laboratory using a variety of steel rods as test specimens. Field tests of the method were conducted at three Corps of Engineers dams. Measurements of the longitudinal and shear velocity were done on rods up to 50 ft long. Not all rods of this length were able to be measured and the quality and consistency of the signal varied. There were fewer problems measuring the longitudinal velocity than shear velocity. While the tension predictions worked in the laboratory tests, the tension could not be accurately calculated for any of the field sites because researchers could not obtain the longitudinal or shear velocities in an unstressed state, or precise measurements of the longitudinal and shear velocities due to the unknown precise length of the rods in the tensioned state.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2021
- Accession Number
- AD1149247
Entities
People
- John M. Carlyle
- Matthew W. Brenner
- Michael K. McInerney
- Robert A. Weber
- Sean W. Morefield
Organizations
- Engineer Research and Development Center