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A Comparative Study on the Mechanical Properties of Laminated Veneer Lumber (LVL) Produced from Blending Various Wood Veneers

https://research.thinkwood.com/en/permalink/catalogue2314
Year of Publication
2019
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
McGavin, Robert
Nguyen, Hoan
Gilbert, Benoit
Dakin, Tony
Faircloth, Adam
Publisher
North Carolina State University
Year of Publication
2019
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Mechanical Properties
Keywords
Hardwood
Cypress
Rotary Peeling
Veneer
Bending Performance
Tension
Bearing Strength
Flatwise Bending
Research Status
Complete
Series
BioResources
Summary
Rotary veneers from spotted gum (Corymbia citriodora) and white cypress pine logs (Callitris glaucophylla) recovered from the native forest in Queensland, as well as Queensland plantation hoop pine (Araucaria cunninghamii) logs were used to manufacture LVL products following six different lay-up strategies including blended species LVL. The different lay-up strategies were to determine the opportunities for improving the mechanical performance of plantation softwood LVL by including native forest veneers. The manufactured products were evaluated for their bending performance, tension, bearing strength perpendicular to the grain, and longitudinal-tangential shear strength. The all-spotted gum LVL showed superior performance in all testing compared to other construction strategies. Blending even a small amount of spotted gum veneer with plantation hoop pine veneer resulted in improved mechanical performance, especially in flatwise bending. Opportunities exist to develop more optimised construction strategies that target specific product performances while optimising the use of the variable veneer qualities generated from log processing.
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Key Mechanical Properties of Cross-banded Laminated Veneer Lumbers Manufactured from Blending Spotted Gum and Hoop Pine Veneers

https://research.thinkwood.com/en/permalink/catalogue2490
Year of Publication
2019
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
Nguyen, Hoan
McGavin, Robert
Gilbert, Benoit
Bailleres, Henri
Organization
Griffith University
Publisher
North Carolina State University
Year of Publication
2019
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Mechanical Properties
Keywords
Cross-Banded
Mixing Species
Sub-Optimal Native Forest Logs
Modulus of Elasticity
Grading
Bending
Strength
Shear
Research Status
Complete
Series
BioResources
Summary
The main objective of this study was to investigate the key mechanical properties of cross-banded laminated veneer lumbers (LVL-C) manufactured from blending veneers recovered from sub-optimal native forest spotted gum and plantation hoop pine logs. The recovered veneers were separated into three grades based on their dynamic modulus of elasticity (MOE). Additionally, the spotted gum veneers were visually graded to evaluate whether a relationship exists between the MOE-based and visual grades. In total, six 12-ply reference LVL and six mixed-species 12-ply LVL-C panels were manufactured and analyzed for (i) flatwise and edgewise bending performance; (ii) bearing and tension strength perpendicular to the grain; and (iii) longitudinal-tangential shear strength. Little correlation was found between MOE-based and visual grades for the spotted gum veneers. The LVL- C showed flatwise and edgewise MOE up to 24% and 13% lower, respectively, than the reference mixed-species LVL. The flatwise and edgewise modulus of rupture were up to 39% and 19% lower, respectively. On average, the tensile and bearing strengths of the LVL-C were considerably higher than the hoop pine LVL and mixed-species LVL, with the former being approximately three times higher. The manufactured LVL-C showed markedly higher bending properties and tensile strengths than commercial LVL-C products.
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Free
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Capacity and Reliability of LVL Beams Manufactured from Juvenile Hardwood Plantation Logs

https://research.thinkwood.com/en/permalink/catalogue2023
Year of Publication
2018
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Gilbert, Benoit
Bailleres, Henri
Zhang, Hao
McGavin, Robert
Organization
Griffith University
The University of Sydney
Year of Publication
2018
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Mechanical Properties
Keywords
Plantation
Hardwood
Bending Strength
Numerical Models
Capacity
Juvenile Wood
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
This paper summarises parts of the research outcomes of a university-government collaborative project aiming at determining the capacity and reliability of veneer-based structural products manufactured from early to midrotation (juvenile) hardwood plantations logs. Two species planted for solid timber end-products (Eucalyptus cloeziana and Corymbia citriodora) and one species traditionally grown for pulpwood (Eucalyptus globulus) were studied for the manufacture of the new products. Focus of this paper is on LVL beams. To cost-effectively determine the nominal design bending strengths of the new beams, a numerical model was developed. The model was found to accurately predict the strength of LVL beams with an average predicted to experimental ratio of 1.00 with a low coefficient of variation of 0.10. Using an established probabilistic database of the material properties of the veneered resources as model input, Monte-Carlo simulations were then performed. The design strength of the new LVL beams was established and found to be comparable to, and in some cases up to 2.5 times higher than, the ones of commercially available softwood products. Recommendations are also made in the paper on the appropriate capacity factors to be used for various service categories of structures. The proposed capacity factors were found to be 5% to 12% lower than the ones currently used in Australia for beams manufactured from mature softwood logs
Online Access
Free
Resource Link
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