Detection and assessment of wood decay in glulam beams using a decay rate approach

Adam Senalik, Frank C. Beall, Henrique M Reis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A glulam beam retired from the field and without visible indications of wood decay was used. Towards detection and assessing wood decay, X-ray computer tomography and ultrasonic measurements were carried out. It was observed that decrease in mass density with increasing levels of wood decay affects x-rays attenuation and allows radioscopy to detect and assess wood decay. To detect and assess decay when only one lateral side of the beam is available, a modified impulse-echo is presented. The modified impulse-echo approach is based on observing the dynamic response of each lamina in the glulam beam to the drop of a steel sphere onto a steel plate coupled to the glulam beam lamina and upon a decay rate analysis of the corresponding time domain signal in a frequency band of interest. The selection of the frequency band of interest only requires knowledge of the nominal transverse dimensions of each lamina in the beam and of the corresponding wood species. It was observed that decay rate analysis allows detection and assessment of wood decay. The decay rate approach leads to an overall rate of false calls of 7.2%. Considering the variability that exists in wood including the presence of splits, orientation and thickness of growth rings, etc., this relative low rate of false calls makes this approach very attractive. Results show that results from both X-ray computer tomography and impulse-echo decay-rated based measurements are consistent with each other and can be used to detect and assess wood decay in structural lumber.

Original languageEnglish (US)
Title of host publicationSensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010
Volume7647
DOIs
StatePublished - Jun 18 2010
EventSensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010 - San Diego, CA, United States
Duration: Mar 8 2010Mar 11 2010

Other

OtherSensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010
CountryUnited States
CitySan Diego, CA
Period3/8/103/11/10

Keywords

  • Glulam beams
  • Impulse-echo
  • Structural lumber
  • Wood decay
  • X-ray computer tomography

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Senalik, A., Beall, F. C., & Reis, H. M. (2010). Detection and assessment of wood decay in glulam beams using a decay rate approach. In Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010 (Vol. 7647). [76471L] https://doi.org/10.1117/12.843603