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19 records – page 1 of 2.

Adhesive Bonding of Structural Hardwood Elements

https://research.thinkwood.com/en/permalink/catalogue75
Year of Publication
2015
Topic
Mechanical Properties
Serviceability
Moisture
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Author
Hassani, Mohammad
Organization
ETH Zurich
Year of Publication
2015
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Serviceability
Moisture
Keywords
Abaqus
Adhesives
Beech
Bonding
Delamination
Finite Element Model
Fracture
Long-term
Model
Hardwood
Research Status
Complete
Summary
The current research investigated the delamination process of adhesively bonded hardwood (European beech) elements subject to changing climatic conditions. For the study of the long-term fracture mechanical behavior of gluedlaminated components under varying moisture content, the role of moisture development, time- and moisture-dependent responses are absolutely crucial. For this purpose, a 3D orthotropic hygro-elastic, plastic, visco-elastic, mechano-sorptive wood constitutive model with moisture-dependent material constants was presented in this work. Such a comprehensive material model is capable to capture the true historydependent stress states and deformations which are essential to achieve reliable design of timber structures. Besides the solid wood substrates, the adhesive material also influences the interface performance considerably. Hence, to gain further insight into the stresses and deformations generated in the bond-line, a general hygro-elastic, plastic, visco-elastic creep material model for adhesive was introduced as well. The associated numerical algorithms developed on the basis of additive decomposition of the total strain were formulated and implemented within the Abaqus Finite Element (FE) package. Functionality and performance of the proposed approach were evaluated by performing multiple verification simulations of wood components, under different combinations of mechanical loading and moisture variation. Moreover, the generality and efficiency of the presented approach was further demonstrated by conducting an application example of a hybrid wood element.
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Analysis of Economic Feasibility of Ash and Maple Lamella Production for Glued Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2225
Year of Publication
2019
Topic
Cost
Material
Glulam (Glue-Laminated Timber)

Applicability of Various Wood Species in Glued Laminated Timber - Parameter Study on Delamination Resistance and Shear Strength

https://research.thinkwood.com/en/permalink/catalogue592
Year of Publication
2014
Topic
Mechanical Properties
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Jiang, Yuan
Schaffrath, Jörg
Knorz, Markus
Winter, Stefan
Van de Kuilen, Jan-Willem
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Connections
Keywords
Hardwood
Softwood
Gluability
Delamination
Shear Strength
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
In a current research project the gluability of various soft- und hardwood species and their applicability in glued laminated timber are investigated. The influence of the processing parameters on the delamination resistance and shear strength of the glue lines are presented in this work. The bonding forces, which are necessary for the integrity of a glue line, act in the interface within a distance that varies from nanometers to micrometers. The parameters that may have significant influence on the bonding strength and durability of adhesive joints are numerous and depend on the type of wood, adhesive and processing conditions.
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Bondline Shear Strength and Wood Failure of European and Tropical Hardwood Glulams

https://research.thinkwood.com/en/permalink/catalogue1372
Year of Publication
2018
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Aicher, Simon
Ahmad, Zakiah
Hirsch, Maren
Publisher
Springer Berlin Heidelberg
Year of Publication
2018
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Keywords
Keruing
Melangangai
Light Red Meranti
Sweet Chestnut
Oak
Beech
Ash
Teak
Hardwood
Shear Strength
Bondlines
Adhesives
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
The study reports on block shear investigations with bondlines of face-glued laminations and matched solid wood specimens from hardwood glulam (GLT) beams produced industrially from eight technically and stand volume-wise important species. The European hardwoods comprised oak, beech, sweet chestnut and ash and the tropical species were teak, keruing, melangangai and light red meranti. The adhesives were phenol-resorcinol and melamine-urea. When combining all species in one sample, a rather strong linear relationship of bond and wood shear strength was observed. The ratio of bond vs. wood shear strength was for all species on the mean value level = 0.9, and likewise (with one exception) for the respective strengths’ 5%-quantiles. Consistent with literature, the test results showed no significant correlations between bond shear strength and density, wood shear strength and wood failure percentage of individual species, respectively. The investigations render the methodological basics of some international standards on bond quality verification as being inappropriate. New, empirically validated hardwood GLT bond requirements are proposed for discussion and implementation at the CEN and ISO levels. The strength ratio specifications reflect respective ANSI provisions, yet the reference quantity wood shear strength is now determined in an unbiased manner from matched GLT specimens. The wood failure verification proposal is based on the 10%-quantile and mean level for initial type testing and factory production control. The requirements further account for the pronounced difference observed in scatter of wood failure between European and tropical species.
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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
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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

Effects of ACQ Preservative Treatment on the Mechanical Properties of Hardwood Glulam

https://research.thinkwood.com/en/permalink/catalogue253
Year of Publication
2012
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Yang, Te-Hsin
Lin, Chih-Hsien
Wang, Song-Yung
Lin, Far-Ching
Publisher
Springer-Verlag
Year of Publication
2012
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Beech
Delamination
Hardwood
Maple
Modulus of Elasticity
non-destructive methods
Oak
Ultrasonic Wave
Tap Tone Method
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
The purpose of this study is to examine the mechanical properties of ACQ-treated glulam made from three hardwood lumbers. Two nondestructive methods, ultrasonic wave and tap tone method, were also used in this study. The results showed that the dynamic MOE and static MOE of lumbers decreased with increased ACQ preservative retention. ANOVA showed no significant difference in the MOE values of glulam between untreated and ACQ-treated group. However, it was also found that glulam made from red oak lumbers had the highest bending strength retention ratio. The shear strength of the glulam also showed similar results. Finally, no delaminating was found in all glulams after the specimens under soaked and boiled delamination tests.
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Feasibility of Glued Laminated Timber Beams with Tropical Hardwoods

https://research.thinkwood.com/en/permalink/catalogue118
Year of Publication
2013
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Bourreau, Damien
Aimene, Yamina
Beauchêne, Jacques
Thibaut, Bernard
Publisher
Springer
Year of Publication
2013
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Delamination
Hardwood
Phenol-Resorcinol Formaldehyde
Shear
Testing
Tropical Climate
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
A feasibility study of glulam was carried out in French Guiana using local wood species. The aim was to determine gluing parameters affording satisfactory behaviour to manufactured glulam in a tropical climate. Three abundant wood species, with special properties, were selected for the study and Resorcinol-Phenol-Formaldehyde resin was used for bonding. Three industrial parameters were considered: adhesive spread rate, closed assembly time and gluing pressure. Delamination and shearing tests were carried outin accordance with European Standards. The tests revealed the influence of wood properties and manufacturing parameters on joint resistance. In fact, the results showed that specific gravity and the shrinkage coefficientgreatly influenced the gluing step. Indeed, wood with a medium specific gravity needed more adhesive and more pressure than wood with a high specific gravity. In addition, planning and lamella thicknesswere found to affect glue joint resistance.
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Glued-In Rods in Hardwood and Hardwood Laminated Veneer Lumber - Report on a Large Experimental Campaign

https://research.thinkwood.com/en/permalink/catalogue1528
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Vallée, Till
Bletz-Mühldorfer, Oliver
Myslicki, Sebastian
Grunwald, Cordula
Walther, Frank
Bathon, Leander
Year of Publication
2016
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Glued-In Rods
Hardwood
GFRP
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 675-683
Summary
Glued-in rods are to be considered a main research field within timber engineering. While there are still many open questions, significant progress has been achieved with regard to steel bars embedded in softwoods. This paper ambition is extending the knowledge about glued-in rods towards hardwood and hardwood laminated veneer lumber, respectively, towards the use of G-FRP bars therein. For that purpose, an extensive experimental campaign was documented, starting from the extensive characterization of the timber, adhesive, small scale specimens to identify suitable adhesive, and concluded by full-scale specimen tests. The study will allow, by providing a coherent set of material parameters, for hardwood, a much better comparison of existing joint capacity methods of previously developed for softwood.
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Hardwood CLT Program in Southern and Central Ontario

https://research.thinkwood.com/en/permalink/catalogue2762
Year of Publication
2021
Topic
Design and Systems
Cost
Material
CLT (Cross-Laminated Timber)
Author
Li, Xincheng
Publisher
University of Toronto
Year of Publication
2021
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Cost
Keywords
Manufacturing
Hardwood
Research Status
Complete
Summary
Cross-laminated timber (CLT) is a large prefabricated solid engineering plank made of multiple layers of planks glued together and it is primarily used in structures such as the floors, walls, and roofs of buildings. ANSI/APA PRG 320 is the world recognized CLT lumber production standard, and the main raw material of CLT has always been softwood rather than hardwood. However, the bending strength, compressive strength, and shear strength of hardwood CLT lumber are stronger than softwood CLT lumber. The large and underutilized hardwood resources in central and southern Ontario provide a huge resource advantage for the hardwood CLT project. This article uses the Cost-Benefit Assessments model to assess the feasibility of investing in hardwood CLT plants in central and southern Ontario. The results show that the payback period of the hardwood CLT factory is 5 years, and the rate of return on investment of 10 years, 15 years, and 20 years are all-around 11%. This study could strengthen investor confidence and it also identifies the direction for the development of hardwood CLT plants in central and southern Ontario.
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19 records – page 1 of 2.