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15 records – page 1 of 2.

Duration-Of-Load and Size Effects on the Rolling Shear Strength of Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue191
Year of Publication
2015
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Yuan
Organization
University of British Columbia
Year of Publication
2015
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Long-term
Mountain Pine Beetle
Short-term
Duration of Load
Rolling Shear Strength
Torque Loading Tests
Language
English
Research Status
Complete
Summary
In this study, the duration-of-load and size effects on the rolling shear strength of CLT manufactured from MPB-afflicted lumber were evaluated. The study of the duration-of-load effect on the strength properties of wood products is typically challenging; and, additional complexity exists with the duration-of-load effect on the rolling shear strength of CLT, given the necessary consideration of crosswise layups of wood boards, existing gaps and glue bonding between layers. In this research, short-term ramp loading tests and long-term trapezoidal fatigue loading tests (damage accumulation tests) were used to study the duration-of-load behaviour of the rolling shear strength of CLT. In the ramp loading test, three-layer CLT products showed a relatively lower rolling shear load-carrying capacity. Torque loading tests on CLT tubes were also performed. The finite element method was adopted to simulate the structural behaviour of CLT specimens. Evaluation of the rolling shear strength based on test data was discussed. The size effect on the rolling shear strength was investigated. The results suggest that the rolling shear duration-of-load strength adjustment factor for CLT is more severe than the general duration-ofload adjustment factor for lumber, and this difference should be considered in the introduction of CLT into the building codes for engineered wood design.
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Duration-Of-Load Effect on the Rolling Shear Strength of Cross Laminated Timber: Duration-Of-Load Tests and Damage Accumulation Model

https://research.thinkwood.com/en/permalink/catalogue228
Year of Publication
2015
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Yuan
Lam, Frank
Organization
University of British Columbia
Year of Publication
2015
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Duration of Load
Long-term
Mountain Pine Beetle
Rolling Shear Strength
Stiffness
Strength
Stress Distribution
Language
English
Research Status
Complete
Summary
In this study, the duration-of-load (DOL) effect on the rolling shear strength of cross laminated timber (CLT) was evaluated. A stress-based damage accumulation model is chosen to evaluate the DOL effect on the rolling shear strength of CLT. This model incorporates the established short-term rolling shear strength of material and predicts the time to failure under arbitrary loading history. The model was calibrated and verified based on the test data from low cycle trapezoidal fatigue tests (the damage accumulation tests). The long-term rolling shear behaviour of CLT can then be evaluated from this verified model. As the developed damage accumulation model is a probabilistic model, it can be incorporated into a time-reliability study. Therefore, a reliability assessment of the CLT products was performed considering short-term and snow loading cases. The reliability analysis results and factors reflecting the DOL effect on the rolling shear strength of CLT are compared and discussed. The results suggest that the DOL rolling shear strength adjustment factor for CLT is more severe than the general DOL adjustment factor for lumber; and, this difference should be considered in the introduction of CLT into the building codes for engineered wood design.
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Effect of Growth Ring Orientation on the Rolling Shear Properties of Wooden Cross Layer Under Two-Plate Shear Test

https://research.thinkwood.com/en/permalink/catalogue635
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Zhou, Qinyi
Gong, Meng
Chui, Ying Hei
Mohammad, Mohammad
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Growth Ring Orientation
Rolling Shear Modulus
Rolling Shear Strength
Spruce
Two-plate shear test
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The design and application of cross laminated timber (CLT) is s trongly influenced by rolling shear properties of cross layers. Hence, predicting the mechanical behaviour of CLT requires accurate information about its rolling shear properties. In this study, black spruce wood laminates with three different growth ring orientations (flat sawn, in-between, quarter sawn) were edge glued to produce wooden cross layer (WCL). Two-plate shear tests were carried out on WCL to investigate the influence of growth ring orientation on the rolling shear properties. The experimental results showed that the growth ring orientation had a significant effect on rolling shear modulus of WCL, however, almost no effect on the rolling shear strength. The WCL of in-between end grain had the maximum rolling shear modulus of 89MPa and rolling sh ear strength of 2.13 MPa.
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Effects of the Thickness of Cross-Laminated Timber (CLT) Panels Made from Irish Sitka Spruce on Mechanical Performance in Bending and Shear

https://research.thinkwood.com/en/permalink/catalogue990
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Sikora, Karol
McPolin, Daniel
Harte, Annette
Publisher
ScienceDirect
Year of Publication
2016
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Sitka Spruce
Thickness
Bending Stiffness
Rolling Shear Strength
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
An investigation was carried out on CLT panels made from Sitka spruce in order to establish the effect of the thickness of CLT panels on the bending stiffness and strength and the rolling shear. Bending and shear tests on 3-layer and 5-layer panels were performed with loading in the out-of-plane and in-plane directions. ‘Global’ stiffness measurements were found to correlate well with theoretical values. Based on the results, there was a general tendency that both the bending strength and rolling shear decreased with panel thickness. Mean values for rolling shear ranged from 1.0 N/mm2 to 2.0 N/mm2.
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Evaluating Rolling Shear Strength Properties of Cross-Laminated Timber by Short-Span Bending Tests and Modified Planar Shear Tests

https://research.thinkwood.com/en/permalink/catalogue1403
Year of Publication
2017
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Minghao
Publisher
Springer Japan
Year of Publication
2017
Country of Publication
Japan
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Rolling Shear Strength
Non-Edge-Glued
Pine
Thickness
Three Point Bending Test
Planar Shear Tests
Europe
Canada
Language
English
Research Status
Complete
Series
Journal of Wood Science
ISSN
1611-4663
Summary
This paper presents an experimental study on rolling shear (RS) strength properties of non-edge-glued cross-laminated timber (CLT) made out of New Zealand Radiata pine (Pinus radiata) structural timber. CLT specimens with 35 and 20 mm thick laminations were studied to evaluate the influence of lamination thickness on the RS strength of CLT. Short-span three-point bending tests were used to introduce high RS stresses in cross layers of CLT specimens and facilitate the RS failure mechanism. Modified planar shear tests from the conventional two-plate planar shear tests were also used to evaluate the RS strength properties. It was found that two test methods yielded comparable RS strength properties and the lamination thickness significantly affected RS strength of the CLT specimens. The test results also indicated that the recommended characteristic RS strength values of CLT products in Europe and Canada might be over conservative. Also, it might be more efficient to specify different RS strength values for CLT with different lamination thickness given the minimum width-to-depth ratio of laminations is satisfied.
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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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Hybrid Beech and Spruce Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1547
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Aicher, Simon
Hirsch, Maren
Christian, Zachary
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Beech
Rolling Shear Modulus
Rolling Shear Strength
Shear Tests
Compression Shear
Bending Tests
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1147-1155
Summary
The presented work examines the rolling shear properties of beech wood for the novel application as cross-layers in hybrid cross-laminated timber. Rolling shear modulus and strength of beech were determined by three different approaches: i) two-plate shear tests on single beech board slabs, and ii) compression shear and iii) bending tests on hybrid CLT specimens based on the test methods defined in EN 16351. The CLT specimens were cut from two industrially manufactured hybrid three-layered CLT-plates with a beech cross-layer and spruce outer layers. The rolling shear modulus results obtained from the single board tests and the bending tests agreed well and were within the range of 350 - 370 N/mm². The characteristic rolling shear strength obtained from the bending tests was determined as 2.6 N/mm², where the failure was often governed by longitudinal shearing of the spruce laminations. Hybrid CLT-plates demonstrate a highly improved strength and deflection behaviour versus homogenous spruce CLT-plates and result in not only a mechanically superior product but also allow for a greatly simplified design approach.
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Influence of Lamination Aspect Ratios and Test Methods on Rolling Shear Strength Evaluation of Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2367
Year of Publication
2019
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Li, Minghao
Dong, Wenchen
Lim, Hyungsuk
Year of Publication
2019
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Mechanical Properties
Keywords
Rolling Shear Strength
Lamination Aspect Ratio
Short-Span Bending
Numerical Modelling
Douglas-Fir
Radiata Pine
Language
English
Research Status
Complete
Series
Journal of Materials in Civil Engineering
Summary
Rolling shear (RS) strength may govern load carrying capacity of cross laminated timber (CLT) subjected to high out-of-plane loading because high RS stresses may be induced in cross layers and wood typically has low RS strength. This study investigates RS strength properties of none-edge-glued CLT via experimental testing (short-span bending tests and modified planar shear tests) and numerical modelling. CLT specimens with different manufacturing parameters including two timber species (New Zealand grown Douglas-fir and Radiata pine), three lamination thickness (20 mm, 35 mm, and 45 mm) and various lamination aspect ratios (4.1~9.8) were studied. The lamination aspect ratio was found to have a substantial impact on RS strength of CLT. Higher aspect ratios led to a significant increase of RS strength and an approximately linear relationship could be established. With similar lamination aspect ratios, the Radiata pine CLT had higher RS strength than the Douglas-fir CLT. The two different test methods, however, yielded comparable RS strength assessments. Numerical models were further developed to study the influence of the test configurations and gaps in the cross layers on stress distributions in the cross layers. It was also found the compressive stresses perpendicular to grain in cross layers had negligible influence on the RS strength evaluations.
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The Influence of Panel Lay-Up on the Characteristic Bending and Rolling Shear Strength of CLT

https://research.thinkwood.com/en/permalink/catalogue2119
Year of Publication
2018
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems

The Influence of Panel Lay-Up on the Characteristic Bending and Rolling Shear Strength of CLT

https://research.thinkwood.com/en/permalink/catalogue2179
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
O’Ceallaigh, Conan
Sikora, Karol
Harte, Annette
Publisher
MDPI
Year of Publication
2018
Country of Publication
Switzerland
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Strength
Lay-up
Rolling Shear Strength
Bending Strength
Language
English
Research Status
Complete
Series
Buildings
ISSN
2075-5309
Online Access
Free
Resource Link
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15 records – page 1 of 2.