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Investigation of Gluelines Block Shear Strength of Norway Spruce Glulam Joints in a Cold Climate

https://research.thinkwood.com/en/permalink/catalogue526
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Wang, Alice
Björnberg, Jonatan
Hagman, Olle
Ahmed, Sheikh
Wan, Hui
Niemz, Peter
Publisher
North Carolina State University
Year of Publication
2016
Country of Publication
United States
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Melamine Urea Formaldehyde
Phenol-Resorcinol Formaldehyde
Adhesives
Block Shear Strength
Temperature
Climate
Melamine Formaldehyde
Language
English
Research Status
Complete
Series
BioResources
Summary
Cross laminated timber (CLT) has been developed to a worldwide well-known and versatile useable building material. Currently increasing rates in production volume and distribution can be observed. In fact CLT, thanks to its laminar structure making it well suited for use in construction, provides new horizons in timber engineering, in areas which had until now been the realm of mineral building materials like concrete and masonry. After a short introduction, this paper aims to demonstrate current production processes used for rigid CLT. In section 2 the process steps are described and essential requirements, as well as pros and cons of various production techniques, are discussed. Latest results of R & D and of development and innovation in production technology are presented. In section 3 test and monitoring procedures in the area of the internal quality assurance, known as factory production control (FPC), are presented. Diverse regulations, in the form of technical approvals for CLT as well as in the CLT product standard prEN 16351 [1], are discussed. Additionally, some technological aspects of the product, CLT, together with a comparison of geometrical and production relevant parameters of current technical approvals in Europe are provided in section 4. In the final and main part of the paper, production and technology is presented in a condensed way. The outlook for current and future developments, as well as the ongoing establishment of the solid construction technique with CLT, is given. The product, CLT, comprises an enormous potential for timber engineering as well as for society as a whole. Standardisation and further innovation in production, prefabrication, joining technique, building physics and building construction make it possible for timber engineering to achieve worldwide success.
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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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Block Shear Strength and Delamination of Cross-Laminated Timber Fabricated with Japanese Larch

https://research.thinkwood.com/en/permalink/catalogue1220
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Gong, Yingchun
Wu, Guofang
Ren, Haiqing
Publisher
North Carolina State University
Year of Publication
2016
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Larch
Delamination
Block Shear Strength
Temperature
One-Component Polyurethane
Language
English
Research Status
Complete
Series
BioResources
Summary
Process parameters of cross-laminated timber (CLT) fabricated with Japanese larch were evaluated. The process parameters were designed by using an orthogonal test including pressure, glue consumption, and adhesive. Both delamination and block shear tests were conducted on CLT in accordance with GB/T 26899 (2011). The results showed that the optimum process parameters were A2B3C2 including pressure (1.2 MPa), glue consumption (200g/m2), and amount of sdhesive (one-component plyurethane). The weight loss and moisture absoption increased when the temperature increased, but the block shear strength decreased as the temperature was raised from 20C to 230C.
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Block Shear Failure Mode of Axially Loaded Groups of Screws

https://research.thinkwood.com/en/permalink/catalogue1512
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Solid-sawn Heavy Timber
Author
Mahlknecht, Ursula
Brandner, Reinhard
Augustin, Manfred
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Solid-sawn Heavy Timber
Topic
Connections
Mechanical Properties
Keywords
Self-Tapping Screws
Block Shear Model
Stiffness
Strength
Bending Stresses
Axially-Loaded
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 362-371
Summary
Self-tapping screws are efficient and flexible fasteners, applicable for many types of connections. Investigations on axially loaded groups of screws pointed out, that small spacing between the screws lead to block shear failure mode. So far, block and plug shear failure mode are only analysed for laterally loaded fasteners. Corresponding models cannot be simple transferred to primary axially loaded screws, because of their load insertion continuously along the effective thread featuring a thread-fibre angle perpendicular or with an angle to grain. Results gained by means of two different test configurations, with constant 90° thread-fibre angle but different configurations of group of screws and support conditions are presented. A block shear model is presented, and for mean values for stiffness and strength properties as model parameters are discussed together with values for parameters related to the force distribution over the effective thread length for the first test configuration. Agreement between model and test results was found on a conservative basis. As outlook, considerations of additional bending stresses as well as parameter optimisation are seen as prerequisites and next steps for further model improvement and practicality.
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Evaluation of the Block Shear Resistance of Glulam Manufactured from Borate-Treated Lamina Wthout Planing After Treatment

https://research.thinkwood.com/en/permalink/catalogue367
Year of Publication
2015
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Bridges and Spans
Author
Stirling, Rod
Feng, Martin
Morris, Paul
Organization
FPInnovations
Year of Publication
2015
Country of Publication
Canada
Format
Report
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Bridges and Spans
Topic
Mechanical Properties
Keywords
Preservative
Borate
Canada
Shear Resistance
Polyurethane
Language
English
Research Status
Complete
Summary
Effective preservative treatments for Canadian glulam products are needed to maintain markets for mass timber on building facades, access markets with significant termite hazards, and expand markets for wood bridges. For all three applications, borate-treatment of lamina before gluing would be preferred as it would lead to maximum preservative penetration. However, the need to plane after treatment and prior to gluing removes the best-treated part of the wood, and creates a disposal issue for treated planer shavings. The present research evaluates the block shear resistance of glulam prepared from untreated and borate-treated lamina with a polyurethane adhesive. Borate treatment was associated with a small but statistically significant loss in median shear strength when evaluated dry; however, there was no difference between the performance of untreated and borate-treated samples when exposed to the vacuum-pressure soak/dry or the boil-dry-freeze/dry procedures. Further work is needed to modify the composition or application of the resin to improve shear strength for glulam applications and ensure consistent performance. However, overall, these data indicate that samples prepared from borate-treated lamina perform similarly in terms of block shear resistance to those prepared from untreated lamina.
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Pull-compression Tests on Glued-in Metric Thread Rods Parallel to Grain in Glulam and Laminated Veneer Lumber of Different Timber Species

https://research.thinkwood.com/en/permalink/catalogue2524
Year of Publication
2016
Topic
Mechanical Properties
Design and Systems
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)

Prediction of Shear Performance on Cross Laminated Timber Wall with Wall to Wall Connections

https://research.thinkwood.com/en/permalink/catalogue1781
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Oh, Jung-Kwon
Hong, Jung-Pyo
Kim, Chul-Ki
Pang, Sung-Jun
Lee, Hyeon-Jeong
Jang, Sung-Il
Park, Moon-Jae
Lee, Jun-Jae
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Mechanical Properties
Keywords
Shear Performance
Failure Mode
Displacement
Peak Load
Model
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 5503-5510
Summary
A cross-laminated timber (CLT) wall plays a role of resisting shear stress induced by lateral forces as well as resisting vertical load. Due to the press size, CLT panels have a limitation in its size. To minimize the initial investment, some glulam manufactures wanted to make a shear wall element with small-size CLT panels and panel-to-panel...
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Bending Capacity of Orthogonal and Parallel Glulam T-section Beams

https://research.thinkwood.com/en/permalink/catalogue2476
Year of Publication
2020
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Bridges and Spans
Author
Wang, Jiejun
Yang, Tao
Ning, Fan
Rao, Zhenyu
Publisher
Eastern Macedonia and Thrace Institute of Technology (EMaTTech)
Year of Publication
2020
Country of Publication
Greece
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Bridges and Spans
Topic
Mechanical Properties
Keywords
Bearing Capacity
Stiffness
Integrity
Strain
Deflection
Ultimate Bearing Capacity
Shear Strength
Finite Element Model
Displacement
Failure Mechanism
Ductility
Language
English
Research Status
Complete
Series
Journal of Engineering Science and Technology Review
ISSN
1791-2377
Online Access
Free
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Evaluation of Horizontal Shear Performance of Larch CLT Walls According to the Edge Connection Shape

https://research.thinkwood.com/en/permalink/catalogue2205
Year of Publication
2019
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Song, Yo-Jin
Hwan Lee, In
Hong, Soon-Il
Publisher
VUPC
Year of Publication
2019
Country of Publication
Slovakia
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Mechanical Properties
Keywords
Shear Performance
Shear Walls
Larch
Cyclic Tests
Half-Lap
Language
English
Research Status
Complete
Series
Wood Research
Online Access
Free
Resource Link
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Evaluating Rolling Shear Strength Properties of Cross Laminated Timber by Torsional Shear Tests and Bending Test

https://research.thinkwood.com/en/permalink/catalogue307
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Minghao
Lam, Frank
Li, Yuan
Year of Publication
2014
Country of Publication
New Zealand
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
SPF
Polyurethane
Rolling Shear Strength
Torsional Shear Test
Bending Test
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
This paper presents a study on evaluating rolling shear (RS) strength properties of cross laminated timber (CLT) using torsional shear tests and bending tests. The CLT plates were manufactured with Spruce-Pine-Fir boards and glued with polyurethane adhesive. Two types of layups (3-layer and 5-layer) and two clamping pressures (0.1 MPa and 0.4 MPa) were studied. For the torsional shear tests, small shear block specimens were sampled from the CLT plates and the cross layers were processed to have an annular cross section. Strip specimens were simply sampled from the CLT plates for the bending tests. Based on the failure loads, RS strength properties were evaluated by torsional shear formula, composite beam formulae as well as detailed finite element models, respectively. It was found that the two different test methods yielded different average RS strength value for the same type of CLT specimens. The test results showed that the CLT specimens pressed with the higher clamping pressure had slightly higher average RS strength. The specimens with thinner cross layers also had higher RS strength than the specimens with thicker cross layers.
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10 records – page 1 of 1.