Thesis
Development of a stress wave timing prototype to detect decay in wood guardrail posts
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/101877
Abstract
Washington State has an estimated 2500 miles of installed guardrail posts, which corresponds to approximately two million guardrail posts. Many of these are wood posts and are subject to decay or deterioration as they age. However, due to the nature of decay in preservative treated wood posts, it is difficult to detect the presence and level of decay by visual means. If decayed guardrail posts remain in service, they represent a safety risk for motorists and are a potential liability for state departments of transportation (DOTs). Non-destructive testing (NDT) of wood has been researched for more than 40 years, and some of this technology is promising for detecting decay in wood guardrail posts. The objectives of this research were to: 1. determine the current state of the art of wood guardrail post inspection in North America and 2. develop a viable inspection methodology for wood guardrail posts. This was accomplished through a review of literature, along with a survey sent to DOTs across the United States and Canada. Next, a nondestructive evaluation prototype device was developed with an industrial partner and then refined through laboratory and field testing. Finally, a testing procedure was recommended for field evaluation of wood guardrail posts. Stress wave timing (SWT) was identified as the most appropriate NDT approach to inspect wood guardrail posts, due to its well documented history of use for the inspection of wood components, compactness, usability on rough wood, cost effectiveness, and general ease of use. Results from the survey indicated that, while many DOTs in the US and Canada allow new installation of wood guardrail systems, often minimal or no inspection procedures are in place for these wood assets. Thus, a prototype stress wave timer was developed, with an accuracy rate of 86% for detecting wood guardrail posts with decay during laboratory testing. The prototype also successfully characterized posts during a field test. It was concluded that the device should be used in conjunction with drilling (for posts with suspected decay) for maximum effectiveness.
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Details
- Title
- Development of a stress wave timing prototype to detect decay in wood guardrail posts
- Creators
- Evan Scott Elszko
- Contributors
- Donald A. Bender (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
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900524865801842
- Language
- English
- Resource Type
- Thesis