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10 records – page 1 of 1.

Characteristics of the Radio-Frequency/Vacuum Drying of Heavy Timbers for Post and Beam of Korean Style Housings Part II: For Korean Red Pine Heavy Timbers with 250 × 250 mm, 300 × 300 mm in Cross Section and 300 mm in Diameter, and 3,600 mm in Length

https://research.thinkwood.com/en/permalink/catalogue1508
Year of Publication
2011
Topic
Moisture
Material
Solid-sawn Heavy Timber
Application
Wood Building Systems
Author
Lee, Nam-Ho
Zhao, Xue-Feng
Shin, Ik-Hyun
Park, Moon-Jae
Park, Jung-Hwan
Park, Joo-Saeng
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2011
Country of Publication
Korea
Format
Journal Article
Material
Solid-sawn Heavy Timber
Application
Wood Building Systems
Topic
Moisture
Keywords
Radio-Frequency/Vacuum Drying
Moisture Gradient
Shrinkage
Case Hardening
Surface Checks
Compressive Load
Language
Korean
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
This study examined the characteristics of radio-frequency/vacuum dried Korean red pine (Pinus densoflora heavy timbers with 250 × 250 mm (S), 300 × 300 mm (L) in cross section and 300 mm in diameter, and 3,600 mm in length, which were subjected to compressive loading after a kerf pretreatment. The following results were obtained : The drying time was short and the drying rate was high in spite of the large cross section of specimens. The moisture gradient inall specimens was gentle in both longitudinal and transverse directions owing to dielectric heating. The shrinkage of the width in the direction perpendicular to was 21 percent ~ 76 percent of that of the thickness of square timbers in the direction parallel to the mechanical pressure. The casehardening for all specimens was very slight because of significantly reduced ratio of the tangential to radial shrinkage of specimens and kerfing. The surface checks somewhat severely occurred although the occurrence extent of the surface checks on the kerfed specimens was slight compared withthat on the control specimen.
Online Access
Free
Resource Link
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Hygrothermal Properties of Cross Laminated Timber and Moisture Response of Wood at High Relative Humidity

https://research.thinkwood.com/en/permalink/catalogue12
Year of Publication
2012
Topic
Moisture
Material
CLT (Cross-Laminated Timber)

Long-Term Experimental Investigation of Timber Composite Beams in Cyclic Humidity Conditions

https://research.thinkwood.com/en/permalink/catalogue636
Year of Publication
2014
Topic
Serviceability
Moisture
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Hailu, Mulugheta
Shrestha, Rijun
Crews, Keith
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Serviceability
Moisture
Keywords
Creep
Eurocode 5
Relative Humidity
Moisture Content
Mechanosorption
Long-term
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
A long term laboratory investigation on two six-meter-span timber composite beams was started from March 2012 at the University of Technology Sydney. These timber composites were made of laminated veneer lumber (LVL). The web and the flanges of the composite timber section were connected using screw-gluing technique. The specimens have been under sustained loads of (2.1kPa) and the environmental conditions was cyclically alternated between normal and very humid conditions whilst the temperature remained quasi constant (22 °C) –typical cycle duration was six to eight weeks. With regard to EC 5, the environmental conditions can be classified as service class 3 where the relative humidity of the air exceeds 85% and the moisture content of the timber samples reaches 20%. During the test, the mid-span deflection, moisture content of the timber beams and relative humidity of the air were continuously monitored. The paper presents the results and observations of the long-term test to-date and the test is continuing.
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Free
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Wetting and Drying Performance and On-site Moisture Protection of Nail-Laminated Timber Assemblies

https://research.thinkwood.com/en/permalink/catalogue1871
Year of Publication
2016
Topic
Moisture
Material
NLT (Nail-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems

Dimensional Changes of Cross-Laminated Specimens Produced under Different Conditions due to Humidity Variation

https://research.thinkwood.com/en/permalink/catalogue2474
Year of Publication
2019
Topic
Moisture
Material
CLT (Cross-Laminated Timber)

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.
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Free
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Creep Behavior of Laminated Veneer Lumber from Poplar Under Cyclic Humidity Changes

https://research.thinkwood.com/en/permalink/catalogue2480
Year of Publication
2019
Topic
Mechanical Properties
Moisture
Material
LVL (Laminated Veneer Lumber)
Author
Li, Chao
Huang, Yuxiang
Publisher
North Carolina State University
Year of Publication
2019
Country of Publication
United States
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Moisture
Keywords
Mechanosorption Creep
Humidity
Four Point Bending Test
Adsorption
Language
English
Research Status
Complete
Series
BioResources
ISSN
1930-2126
Online Access
Free
Resource Link
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Design of Controlled Rocking Heavy Timber Walls For Low-To-Moderate Seismic Hazard Regions

https://research.thinkwood.com/en/permalink/catalogue2370
Year of Publication
2016
Topic
Seismic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Kovacs, Michael
Publisher
McMaster University
Year of Publication
2016
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Seismic
Design and Systems
Keywords
Controlled Rocking
Heavy Timber
Low-to-Moderate Seismic Hazard
Post-Tensioned Timber
Force-Based Design
Non-Linear Time-History Analysis
Language
English
Research Status
Complete
Summary
The controlled rocking heavy timber wall (CRHTW) is a high-performance structural solution that was first developed in New Zealand, mainly considering Laminated Veneer Lumber (LVL), to resist high seismic loads without sustaining structural damage. The wall responds in bending and shear to small lateral loads, and it rocks on its foundation in response to large seismic loads. In previous studies, rocking has been controlled by both energy dissipation elements and post-tensioning, and the latter returns the wall to its original position after a seismic event. The controlled rocking response avoids the need for structural repair after an earthquake, allowing for more rapid return to occupancy than in conventional structures. Whereas controlled rocking walls with supplemental energy dissipation have been studied before using LVL, this thesis proposes an adapted CRHTW in which the design and construction cost and complexity are reduced for low-to-moderate seismic hazard regions by removing supplemental energy dissipation and using cross-laminated timber (CLT) because of its positive economic and environmental potential in the North American market. Moreover, whereas previous research has focussed on direct displacement-based design procedures for CRHTWs, with limited consideration of force-based design parameters, this thesis focusses on force-based design procedures that are more common in practice. A design and analysis process is outlined for the adapted CRHTW, based on a similar methodology for controlled rocking steel braced frames. The design process includes a new proposal to minimize the design forces while still controlling peak drifts, and it also includes a new proposal for predicting the influence of the higher modes by referring to previous research on the capacity design of controlled rocking steel braced frames. Also, a numerical model is outlined, including both a baseline version and a lower-bound model based on comparison to experimental data. The numerical model is used for non-linear time-history analysis of a prototype design, confirming the expected performance of the adapted CRHTW, and the model is also used for incremental dynamic analyses of three-, six-, and nine-storey prototypes, which show a low probability of collapse.
Online Access
Free
Resource Link
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Wetting and Drying Performance Related To On-Site Moisture Protection of Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1169
Year of Publication
2018
Topic
Moisture
Site Construction Management
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Wood Building Systems
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2018
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Wood Building Systems
Topic
Moisture
Site Construction Management
Keywords
On-Site
Moisture Management
Water Repellants
Rain
Language
English
Research Status
Complete
Summary
Practical solutions are needed for on-site moisture management of mass timber construction. Six groups of cross-laminated timber (CLT) specimens, together with reference specimens including plywood, OSB, and nail-laminated timber were assessed for their wetting and drying behaviour. The focus of this study was to assess the effectiveness of water repellents and membranes installed on CLT in preventing the wetting that can be caused by, for example, rain during outdoor exposure, installation of wet concrete topping, or sitting on a damp concrete slab. Seven water repellent products covering a range of formulations and three membranes including a self-adhered vapour-permeable membrane, a self-adhered vapour-impermeable membrane, and a lumber wrap were assessed as potential temporary moisture protection measures. Implications for moisture protection practices based on the test were summarized at the end of this report.
Online Access
Free
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Characterizing High Temperature Performance of Structural Adhesives

https://research.thinkwood.com/en/permalink/catalogue2258
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Organization
Université Laval
Country of Publication
Canada
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Topic
Fire
Keywords
Bonding
Research Status
In Progress
Notes
Contact: Christian Dagenais, Université Laval
Summary
Structural engineered woods require the use of previously evaluated structural adhesives in accordance with a variety of standard methods (ASTM D2559, ASTM D7247, CSA O112.9, CSA O112.10, CSA O177, etc.). The basic assumption is that a bonded engineered wood product will have a performance equivalent to, or better than, the non-bonded product it replaces, regardless of the conditions of use (dry, wet, fire, etc.). Nevertheless, the results of cross-laminated wood (CLT) fire tests have shown that the requirements currently imposed on adhesives do not allow to limit lamellae detachment when CLT is exposed to fire. Traditionally, this behavior is not observed for glulam. It is essential to review the classification and performance criteria imposed on adhesives by submitting them to the various tests currently standardized. The analysis of the results may also be used to develop a new test method for adhesives exposed to high temperatures, depending on the anticipated use of the engineered wood product.
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10 records – page 1 of 1.