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Advanced Quality and In-Service Condition Assessment Procedures for Mass Timber and Cross-Laminated Timber Products

https://research.thinkwood.com/en/permalink/catalogue2558
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Organization
Forest Products Laboratory
Mississippi State University
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Non-Destructive Evaluation
Bond Performance
Monitoring Techniques
Serviceability
Quality Assurance
Research Status
In Progress
Notes
Project contacts are Frederico França at Mississippi State University and Robert J. Ross at the Forest Products Laboratory
Summary
With the rapid development of CLT manufacturing capacity around the world and the increasing architectural acceptance and adoption, there is a current and pressing need regarding adhesive bond quality assurance in manufacturing. As with other engineered glued composites, adhesive bondline performance is critically important. Bondline assessment requires technology in the form of sensors, ultrasonics, load cells, or other means of reliable machine evaluation. The objectives of this cooperative study are to develop quality assurance procedures for monitoring the quality of mass timber and CLT during and after manufacturing and to develop assessment techniques for CLT panels in-service.
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Delamination Detection in a 90-Year-Old Glulam Block with Scanning Dry Point-Contact Ultrasound

https://research.thinkwood.com/en/permalink/catalogue114
Year of Publication
2013
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Neuenschwander, Jürg
Sanabria, Sergio
Schuetz, Philipp
Widmann, Robert
Vogel, Mareike
Organization
Swiss Federal Laboratories for Materials Science and Technology
Publisher
De Gruyter
Year of Publication
2013
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Keywords
Bonding
Delamination
Inspection
Non-Destructive Evaluation
Research Status
Complete
Series
Holzforschung
Summary
Glued laminated timber (glulam) is known in timber constructions since more than 100 years. Glulam members can delaminate due to aging and excessive changes of temperature and humidity. This results in significantly reduced load bearing capability of the affected structural members. This contribution focuses on the ultrasonic point-contact inspection of gluing plane delamination as a nondestructive method. Ultrasonic measurements on a section of a 90-year old roofing glulam member are presented. The results are compared with manual detection and evaluation of delamination with a feeler gauge, with X-ray computed tomography analyses, and with numerical simulations. Appropriate data evaluation of the mechanized ultrasonic results allows the determination of material separation that are deeper than 20 mm in the signature of the surface wave and large-scale delamination (> 80% of the complete bonding width) in the back-wall echo. Numerical simulations based on the finite-difference time-domain method shed light into the details of the wave propagation and support the experimental findings.
Online Access
Free
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Effectiveness of Several NDE Technologies in Detecting Moisture Pockets and: Artificial Defects in Sawn Timber and Glulam

https://research.thinkwood.com/en/permalink/catalogue778
Year of Publication
2016
Topic
Serviceability
Material
Glulam (Glue-Laminated Timber)
Solid-sawn Heavy Timber
Application
Bridges and Spans
Author
Wacker, James
Senalik, Christopher
Wang, Xping
Jalinoos, Frank
Year of Publication
2016
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Solid-sawn Heavy Timber
Application
Bridges and Spans
Topic
Serviceability
Keywords
Decay
Douglas-Fir
Moisture Pockets
Non-Destructive Evaluation
Scanning
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria
Summary
Several nondestructive evaluation (NDE) technologies were studied to determine their efficacy as scanning devices to detect internal moisture and artificial decay pockets. Large bridge-sized test specimens, including sawn timber and glued-laminated timber members, were fabricated with various internal defects. NDE Technologies evaluated in this research were ground penetrating radar (GPR), microwave scanning, ultrasonic pulse velocity, ultrasonic shear wave tomography, and impact echo methods. Each NDE technology was used to evaluate a set of seven test specimens over a 2-day period and then raw data scans were processed into two-dimensional, internal defect maps. Several parameters were, compared including the relative size, orientation, and moisture conditions of the internal defect. GPR was the most promising NDE technology and is currently being more rigorously evaluated within the laboratory. The study results will be useful in the further development of a reliable NDE scanning technique that can be utilized to inspect the primary structural components in historic covered timber bridges.
Online Access
Free
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Field Performance of Timber Bridges: A National Study

https://research.thinkwood.com/en/permalink/catalogue2127
Year of Publication
2013
Topic
Design and Systems
Serviceability
Application
Bridges and Spans

Nondestructive Evaluation of a 75-Year Old Glulam Arch

https://research.thinkwood.com/en/permalink/catalogue246
Year of Publication
2013
Topic
Serviceability
Material
Glulam (Glue-Laminated Timber)
Author
Teder, Marko
Wang, Xiping
Year of Publication
2013
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Serviceability
Keywords
Decay
Delamination
Modulus of Elasticity
Non-Destructive Evaluation
Stress Wave Timing
Wave Propagation
Strength
Resistance Micro-Drilling
Conference
International Nondestructive Testing and Evaluation of Wood Symposium
Research Status
Complete
Notes
September 24-27, 2013, Madison, Wisconsin, USA
Summary
The purpose of this study was to explore the possibilities of using existing nondestructive evaluation (NDE) methods to assess delamination and decay of glulam structures. A glulam arch removed from a research building after more than 75-year service was used as a test specimen. The glulam arch section was tested using stress wave timing, ultrasonic wave propagation, and resistance microdrilling methods at a series of locations. The arch was subsequently cut open for visual inspection and small compression and shear samples were obtained for strength testing. It was found that wave propagation times or wave velocities measured across the laminations were good indicators of internal decay. Stress wave timing and ultrasonic propagation methods were able to detect moderate to large delamination, but not micro-delamination. Resistance micro-drilling was found not effective in detecting delamination. Further research is planned to evaluate the possibility of using pulse-echo method to detect internal delamination of glulam members. Key words: glued laminated timber (glulam), stress wave, ultrasonic wave, resistance micro-drilling, strength, modulus of elasticity.
Online Access
Free
Resource Link
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