Thesis
Nondestructive testing of concrete box girder bridges using thermal imaging
Master of Science (MS), Washington State University
2008
Handle:
https://hdl.handle.net/2376/101842
Abstract
In recent years, thermal imaging has become a common nondestructive inspection method used in the field. This research investigates thermal imaging as a viable option in the detection of simulated voids in post-tensioning ducts in concrete specimens, the simulated void size and orientation with respect to adjacent steel tendons, the application of through-heating with thermal imaging of the unheated concrete surface, the detection of actual voids and delaminations during field inspections of concrete bridges, and the duration of heat input with respect to the quality of thermal images that are obtainable. Field inspections of concrete box girder bridges, along with lab inspections of specimens simulating post-tensioned box girder bridge walls, have led to the following conclusions. First, the method of heating is an essential part of inspection depending on the type and location of defects. Near-surface defects such as delaminations, poorly consolidated concrete, and spalled concrete are detectable with through-thickness heating, as well as with same-surface heating. However, internal defects or embedded material such as post-tensioning ducts or voids inside those ducts are most easily detected with through-thickness heating Additional conclusions from this research involve specimen parameters. Concrete thickness is very important in terms of minimizing heat loss and obtaining a temperature gradient in a known direction. Inspections of 20 cm (8 in.) test specimens resulted in thermal images showing defects and tendons more clearly than inspections of 30 cm (12 in.) test specimens. Also, void size and void orientation with respect to adjacent steel tendons inside the posttensioning ducts is critical. Simulated voids located between the heated surface and the tendons were most often detectable. However, simulated voids located at the same depth as adjacent tendons were not detectable since the steel tended to mask the presence of any simulated voids.
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Details
- Title
- Nondestructive testing of concrete box girder bridges using thermal imaging
- Creators
- Kenneth J. Dupuis
- Contributors
- David Garnet Pollock (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Identifiers
- 99900525384701842
- Language
- English
- Resource Type
- Thesis