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Block Shear Testing of CLT Panels: An Exploratory Study

https://research.thinkwood.com/en/permalink/catalogue2624
Year of Publication
2011
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Casilla, Romulo
Pirvu, Ciprian
Wang, Brad
Lum, Conroy
Organization
FPInnovations
Year of Publication
2011
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Adhesive
Block Shear Test
Failure
Language
English
Research Status
Complete
Summary
A study was conducted with the primary objective of examining the efficacy of a standard block shear test method to assess the bond quality of cross-laminated timber (CLT) products. The secondary objective was to examine the effect of pressure and adhesive type on the block shear properties of CLT panels. The wood material used for the CLT samples was Select grade nominal 25 x 152-mm (1 x 6-inch) Hem-Fir. Three adhesive types were evaluated under two test conditions: dry and vacuum-pressure-dry (VPD), the latter as described in CSA standard O112.10. Shear strength and wood failure were evaluated for each test condition. Among the four properties evaluated (dry and VPD shear strength, and dry and VPD wood failure), only the VPD wood failure showed consistency in assessing the bond quality of the CLT panels in terms of the factors (pressure and adhesive type) evaluated. Adhesive type had a strong effect on VPD wood failure. The different performance levels of the three adhesives were useful in providing insights into how the VPD block shear wood failure test responds to significant changes in CLT manufacturing parameters. The pressure used in fabricating the CLT panels showed a strong effect on VPD wood failure as demonstrated for one of the adhesives. VPD wood failure decreased with decreasing pressure. Although dry shear wood failure was able to detect the effect of pressure, it failed to detect the effect of adhesive type on the bond quality of the CLT panels. These results provide support as to the effectiveness of the VPD block shear wood failure test in assessing the bond quality of CLT panels. The VPD conditioning treatment was able to identify poor bondline manufacturing conditions by observed changes in the mode of failure, which is also considered an indication of wood-adhesive bond durability. These results corroborate those obtained from the delamination test conducted in a previous study (Casilla et al. 2011). Along with the delamination test proposed in an earlier report, the VPD block shear wood failure can be used to assess the CLT bond quality. Although promising, more testing is needed to assess whether the VPD block shear wood failure can be used in lieu of the delamination test. The other properties studied (shear strength and dry wood failure), however, were not found to be useful in consistently assessing bond line manufacturing quality.
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Cost, Time and Environmental Impacts of the Construction of the New NMIT Arts and Media Building

https://research.thinkwood.com/en/permalink/catalogue251
Year of Publication
2011
Topic
Cost
Design and Systems
Energy Performance
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
John, Stephen
Mulligan, Kerry
Perez, Nicolas
Love, Simon
Page, Ian
Organization
University of Canterbury
Year of Publication
2011
Country of Publication
New Zealand
Format
Report
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Cost
Design and Systems
Energy Performance
Keywords
Life Cycle Cost Study
Language
English
Research Status
Complete
Summary
This report was produced by the University of Canterbury for the Ministry of Agriculture and Forestry under Expression of Interest MAF POL 0910-11665. The report covers extensive research carried out on the construction of the new Arts and Media building at Nelson Marlborough Institute of Technology in Nelson, New Zealand, between March 2010 and June 2011. The collaborative research programme was directed by the Department of Civil and Natural Resources Engineering at the University of Canterbury (UC), Christchurch. Major contributions to the research programme were made by third-party industry consultants and reported in separate documents – a copy of all the original reports is included in the Appendices ; ScionResearch - Carbon and Energy Footprint of a new three storey building at Nelson Marlborough Institute of Technology (NMIT), Simon Love (2011); BRANZ (Building Research Association of New Zealand) - Nelson-Marlborough Institute of Technology Arts Building – An assessement of life cycle costs for alternative designs (BRANZ report E568), Ian Page (2010); Aurecon Group and ISJ Architects (working together) – NMIT Alternative Structural Design; Ref. 210688-001 (August, 2010).
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Delamination Testing of CLT Panels: An Exploratory Study

https://research.thinkwood.com/en/permalink/catalogue2626
Year of Publication
2011
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Casilla, Romulo
Pirvu, Ciprian
Wang, Brad
Organization
FPInnovations
Year of Publication
2011
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Adhesive
Bond Quality
Delamination Test
Strength
Language
English
Research Status
Complete
Summary
A study was conducted with the primary objective of examining the efficacy of delamination test using cylindrical core specimens to assess the bond quality of cross laminated timber (CLT) products. A prototype coring drill bit was fabricated to prepare a cylindrical-shaped specimen, the height of which corresponds to the full thickness of the CLT panel. A secondary objective was to examine the effect of pressure, adhesive type, number of plies, and specimen shape on the delamination resistance of CLT panels. The wood material used for the CLT samples was Select grade nominal 1 x 6-inch Hem-Fir boards. Examples of three adhesive types were evaluated, which were designated as A, B, and C. The delamination tests used were as described in CAN / CSA O122-06 and EN 302-2. Cylindrical specimen extracted as core was found satisfactory as a test specimen type for use in delamination testing of CLT product. Its efficacy was comparable to that of a square cross-section specimen. The former is recommended as it can be extracted from thicker panels and from any location in the panel. It would also be more convenient to plug the round hole. Adhesive type had a strong effect on delamination resistance based on the two delamination tests used. Adhesive A exhibited the greatest delamination resistance, followed in decreasing order, by adhesives C and B. It should be noted that no effort was made to find the optimum CLT manufacturing parameters for each type of adhesive. Therefore the relative rankings of the adhesives tested may not be representative. However, for the purposes of this study, the different performance levels from the three adhesives are useful in providing insight into how the proposed delamination test responds to significant changes in CLT manufacturing parameters. Pressure used in fabricating the CLT panel showed a strong effect on delamination resistance as demonstrated for one of the adhesives. Delamination resistance decreased with decreasing pressure. The effect of the number of plies in the CLT panel was dependent upon the type of adhesive, and this was probably related to the adhesive’s assembly time characteristic. These results provide support as to the effectiveness of delamination test in assessing the moisture durability of CLT panels. It was able to differentiate the performance in delamination resistance among different types of adhesives, and able to detect the effect of manufacturing parameters such as pressure and increased number of plies in CLT construction. The test procedure described in CAN / CSA O122-06 appears to be reasonable in the delamination resistance assessment of CLT panels for qualification and quality control testing. Based on the results of the study along with some background information and guidelines, delamination requirements for CLT panels are proposed. The permitted delamination values are greater than those currently specified for laminated and fingerjoined lumber products. This is in recognition of the higher bond line stresses when bonded perpendicular laminations (i.e. CLT) are exposed to the delamination wetting and drying cycles, as opposed to parallel laminations (i.e. glulam or fingerjoints).
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Timber in Multi-Residential, Commercial and Industrial Building: Recognising Opportunities and Constraints

https://research.thinkwood.com/en/permalink/catalogue1932
Year of Publication
2011
Topic
Market and Adoption
Application
Wood Building Systems

Wind-Induced Vibration of Tall Wood Buildings

https://research.thinkwood.com/en/permalink/catalogue1105
Year of Publication
2011
Topic
Wind
Connections
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Wood Building Systems