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Durability of Structural Lumber Products after Exposure at 82C and 80% Relative Humidity

https://research.thinkwood.com/en/permalink/catalogue784
Year of Publication
2005
Topic
Mechanical Properties
Moisture
Material
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Solid-sawn Heavy Timber
Author
Green, David
Evans, James
Hatfield, Cherilyn
Byrd, Pamela
Organization
Forest Products Laboratory
Year of Publication
2005
Country of Publication
United States
Format
Report
Material
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Solid-sawn Heavy Timber
Topic
Mechanical Properties
Moisture
Keywords
Aspen
Douglas-Fir
Modulus of Elasticity
Modulus of Rupture
Southern Pine
Poplar
Relative Humidity
SPF
Temperature
Flexural Properties
Language
English
Research Status
Complete
Summary
Solid-sawn lumber (Douglas-fir, southern pine, Spruce– Pine–Fir, and yellow-poplar), laminated veneer lumber (Douglas-fir, southern pine, and yellow-poplar), and laminated strand lumber (aspen and yellow-poplar) were heated continuously at 82°C (180°F) and 80% relative humidity (RH) for periods of up to 24 months. The lumber was then reconditioned to room temperature at 20% RH and tested in edgewise bending. Little reduction occurred in modulus of elasticity (MOE) of solid-sawn lumber, but MOE of composite lumber products was somewhat reduced. Modulus of rupture (MOR) of solid-sawn lumber was reduced by up to 50% after 24 months exposure. Reductions in MOR of up to 61% were found for laminated veneer lumber and laminated strand lumber after 12 months exposure. A limited scope study indicated that the results for laminated veneer lumber in edgewise bending are also applicable to flatwise bending. Comparison with previous results at 82°C (180°F)/25% RH and at 66°C (150°F)/20% RH indicate that differences in the permanent effect of temperature on MOR between species of solid-sawn lumber and between solid-sawn lumber and composite lumber products are greater at high humidity levels than at low humidity levels. This report also describes the experimental design of a program to evaluate the permanent effect of temperature on flexural properties of structural lumber, with reference to previous publications on the immediate effect of temperature and the effect of moisture content on lumber properties.
Online Access
Free
Resource Link
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Effect of Notches on the Performance of Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2559
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Organization
Forest Products Laboratory
Mississippi State University
Country of Publication
United States
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Notches
Notched Connections
Bending Properties
Flexural Properties
Research Status
In Progress
Notes
Project contacts are Robert J. Ross at the Forest Products Laboratory and Rubin Shmulsky at Mississippi State University
Summary
Notches, particularly when incorporated on the tensile face, influence the ultimate capacity of members, such as beams and floor panels. Understanding and quantification of failure modes, ductility, and strength of notched CLT floor panels can allow the safe application of notches on building construction. Despite wood’s ductility, notches are known areas of stress concentration. The 2018 International Residential Code for one- and two-family dwellings (International Code Council 2017) restricts the use of notches on engineered wood products by requiring structural calculations instead of elucidating the ways notches might be used. To employ CLT to its maximum potential, there is a current and pressing need for better knowledge regarding the influence of notches on flexural performance. This research seeks to review the literature regarding notches in solid and engineered beams, review typical CLT design details that employ or utilized notched panels, and conduct pilot-scale testing of notched CLT panels.
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Effects of Reinforcement Geometry on Strength and Stiffness in Adhesively Bonded Steel-Timber Flexural Beams

https://research.thinkwood.com/en/permalink/catalogue898
Year of Publication
2012
Topic
Mechanical Properties
Material
Steel-Timber Composite
Application
Beams
Author
Alam, Parvez
Ansell, Martin
Smedley, Dave
Publisher
MDPI
Year of Publication
2012
Country of Publication
Switzerland
Format
Journal Article
Material
Steel-Timber Composite
Application
Beams
Topic
Mechanical Properties
Keywords
Finite Element Model
Yield Strength
Volume Fraction
Flexural Properties
Language
English
Research Status
Complete
Series
Buildings
ISSN
2075-5309
Summary
A finite element model is developed to analyse, as a function of volume fraction, the effects of reinforcement geometry and arrangement within a timber beam. The model is directly validated against experimental equivalents and found to never be mismatched by more than 8% in respect to yield strength predictions. Yield strength increases linearly as a function of increasing reinforcement volume fraction, while the flexural modulus follows more closely a power law regression fit. Reinforcement geometry and location of reinforcement are found to impact both the flexural properties of timber-steel composite beams and the changes due to an increase in volume fraction.
Online Access
Free
Resource Link
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Experimental Study on the Effectiveness of Finger Joint with Variations in Wood Species Toward Bending Strength of Glulam Beams

https://research.thinkwood.com/en/permalink/catalogue2457
Year of Publication
2019
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Anshari, Buan
Rofaida, Aryani
Mahmud, Fathmah
Pathurahman
Rahmalia, R.
Publisher
IOP Publishing Ltd
Year of Publication
2019
Country of Publication
United Kingdom
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Finger Joints
Flexural Properties
Rajumas
Sengon
Language
English
Research Status
Complete
Series
IOP Conference Series: Earth and Environmental Science
Online Access
Free
Resource Link
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