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146 records – page 2 of 15.

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
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
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.
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Checking in CLT Panels: An Exploratory Study

https://research.thinkwood.com/en/permalink/catalogue2625
Year of Publication
2011
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Casilla, Romulo
Lum, Conroy
Pirvu, Ciprian
Wang, Brad
Organization
FPInnovations
Year of Publication
2011
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Moisture
Keywords
Panels
Testing Methods
Surface Checks
Moisture Content
Gaps
Research Status
Complete
Summary
A study was conducted with the primary objective of gathering information for the development of a protocol for evaluating the surface quality of cross-laminated timber (CLT) products. The secondary objectives were to examine the effect of moisture content (MC) reduction on the development of surface checks and gaps, and find ways of minimizing the checking problems in CLT panels. The wood materials used for the CLT samples were rough-sawn Select grade Hem-Fir boards 25 x 152 mm (1 x 6 inches). Polyurethane was the adhesive used. The development of checks and gaps were evaluated after drying at two temperature levels at ambient relative humidity (RH). The checks and gaps, as a result of drying to 6% to 10% MC from an initial MC of 13%, occurred randomly depending upon the characteristics of the wood and the manner in which the outer laminas were laid up in the panel. Suggestions are made for minimizing checking and gap problems in CLT panels. The checks and gaps close when the panels are exposed to higher humidity. Guidelines were proposed for the development of a protocol for classifying CLT panels into appearance grades in terms of the severity of checks and gaps. The grades can be based on the estimated dimensions of the checks and gaps, their frequency, and the number of laminas in which they appear.
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Climatological Analysis for Hygrothermal Performance Evaluation: Mid-Rise Wood

https://research.thinkwood.com/en/permalink/catalogue755
Year of Publication
2014
Topic
Moisture
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Cornick, Steve
Swinton, Michael
Organization
National Research Council of Canada
Year of Publication
2014
Format
Report
Material
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Moisture
Keywords
Climate
Hygrothermal
Mid-Rise
Moisture Content
National Building Code of Canada
Water Penetration
Research Status
Complete
Summary
The objective of the task is to select, from the 679 locations in Table C-2 of the 2010 National Building Code of Canada (NBC 2010), several representative locations for which long-term historical weather data exists. This information from these locations can subsequently be used to determine the exterior boundary conditions for input files for hygrothermal simulation programs and hygrothermal testing in the laboratory. This report discusses the selection of locations for the hygrothermal simulation task of the project on Mid-rise Wood Buildings and the determination of spray-rates and pressure differentials for the water penetration testing portion of the project.
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Comparison between Predicted and Measured Moisture Content and Climate in 12 Monitored Timber Structures in Switzerland

https://research.thinkwood.com/en/permalink/catalogue2895
Year of Publication
2021
Topic
Moisture
Application
Wood Building Systems
Author
Schiere, Marcus
Franke, Bettina
Franke, Steffen
Müller, Andreas
Organization
Bern University of Applied Sciences
Editor
Brandner, Reinhard
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Application
Wood Building Systems
Topic
Moisture
Keywords
Moisture Content
Climate
Meteorological Data
Building Standards
Monitoring
Research Status
Complete
Series
Buildings
Summary
Wood is a hygroscopic material that primarily adapts its moisture content to the surrounding relative humidity. The climate in a structure or building depends on the building type and the region the structure is located in. In this study, the effect of region on the moisture content of wood was investigated. Measurements taken in 12 ventilated timber structures were compared to the theoretical equilibrium moisture content calculated from the relative humidity and temperature in 107 meteorological stations across Switzerland. The monitored load-bearing elements were made of softwood and protected from the direct impact of weather. The climatic conditions around the Alps, a mountain range that runs from France to Austria and crosses Switzerland, can be divided into the following three different regions: (1) south of the Alps, where the climate is affected mainly by the Mediterranean sea; (2) north of the Alps, where the climate is affected by the Atlantic Ocean; and (3) the inner Alps, where the climate is considered to be relatively dry. The climatic conditions of the three separate regions were reflected in the measurements made in the monitored timber structures. Differences between the regions were quantified. The moisture content and relative humidity, similarly to temperature, depended on altitude (above sea level).
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Construction Moisture Management, Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2685
Year of Publication
2020
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2020
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
Topic
Moisture
Keywords
Wetting
Risk Mitigation
Drying
Research Status
Complete
Summary
Cross-Laminated Timber (CLT) is an engineered mass timber product manufactured by laminating dimension lumber in layers with alternating orientation using structural adhesives. It is intended for use under dry service conditions and is commonly used to build floors, roofs, and walls. Because prolonged wetting of wood may cause staining, mould, excessive dimensional change (sometimes enough to fail connectors), and even result in decay and loss of strength, construction moisture is an important consideration when building with CLT. This document aims to provide technical information to help architects, engineers, and builders assess the potential for wetting of CLT during building construction and identify appropriate actions to mitigate the risk.
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Free
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Construction moisture management, nail-laminated timber

https://research.thinkwood.com/en/permalink/catalogue2904
Year of Publication
2021
Topic
Moisture
Material
NLT (Nail-Laminated Timber)
Author
Wang, Jieying
Organization
FPInnovations
Year of Publication
2021
Format
Report
Material
NLT (Nail-Laminated Timber)
Topic
Moisture
Keywords
Laminate Product
Wood Frame
Moisture Content
Performance
Research Status
Complete
Series
InfoNote
Summary
Nail-laminated timber (NLT) is a large built-up member often used as interior structural members for floors, roofs, walls, and elevator/stair shafts. Because prolonged wetting of wood may cause staining, mould, excessive dimensional change (sometimes enough to fail fasteners), and even result in decay and loss of strength, construction moisture is an important consideration when building with NLT. This document aims to provide technical information to help architects, engineers, and builders assess the potential for wetting of NLT during building construction and identify appropriate actions to mitigate the risks.
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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
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Moisture
Keywords
Mechanosorption Creep
Humidity
Four Point Bending Test
Adsorption
Research Status
Complete
Series
BioResources
Summary
Many academic studies over the years have confirmed that mechano-sorptive (MS) creep is an inherent characteristic of wood. Unlike solid wood, bond lines are introduced into laminated veneer lumber (LVL), creating a laminated structure with different hygroscopicity. What are the effects of these differences on the MS creep of LVL? In this study, three groups of well-matched LVL samples were subjected to four-point bending loading within different relative humidity cycles. For each group, the applied load ranged from 15% to 35% of the short-term fracture load. The results showed that after the first hygroscopic process, LVL showed irreversible expansion (0.11 mm) and a relatively slow moisture adsorption rate. These made it difficult for LVL to show partial creep recovery during the first adsorption process no matter how low the load level was, while solid wood showed partial creep recovery when the load level was = 25%. The following creep behavior of LVL was similar to that of solid wood: partial creep recovery started from the second adsorption stage when a moderate load level was applied.
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Cross-Laminated Timber Roof Panels at the Promega Corporation Facility: Documenting Installation and Monitoring In-Service Moisture Conditions

https://research.thinkwood.com/en/permalink/catalogue801
Year of Publication
2013
Topic
Serviceability
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Glass, Samuel
Romanin, Jennifer
Schumacher, Jim
Spickler, Kris
Organization
Forest Products Laboratory
Year of Publication
2013
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Moisture
Keywords
Moisture
Temperature
Installation Process
Sensors
Research Status
Complete
Summary
The USDA Forest Products Laboratory (FPL) has, for the past two years, been assisting in removing technical barriers to the use of CLT and trying to develop interest in the United States for its utilization. Coincidentally, Promega Corporation, a leader in providing innovative solutions and technical support to the life sciences industry, is currently constructing a new facility in Fitchburg, Wisconsin, that features CLT. This is the first large-scale commercial utilization of CLT in the United States using CLT manufactured in North America. As with any new building system, it is important for the design and construction community to have information on how CLT is installed and how it performs. The objectives of this research are twofold: (1) to document the CLT installation process with photography and video and (2) to install sensors in the CLT panels and collect data on in-service moisture and temperature conditions.
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Damage Evaluation of Glulam Twinned Columns to Beam Circular Bolted Connection

https://research.thinkwood.com/en/permalink/catalogue166
Year of Publication
2015
Topic
Connections
Moisture
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Columns
Author
Dopeux, Jérôme
Giorgetti, Cosimo
Pop, Octavian
Reynaud, Philippe
Dubois, Frédéric
Year of Publication
2015
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Columns
Topic
Connections
Moisture
Keywords
Moisture Content
Cracks
Bolts
Research Status
Complete
Series
Pro Ligno
Summary
This paper deals with assessment of glulam twinned columns to beam circular bolted connection. This kind of connection is used for embedded assembly. Because of the moisture content variations, cracks often occur in the direction parallel to the grain. The aim of the study is to understand the mechanism responsible of the cracks happening. In the same time, another aim of this study is to evaluate the residual resistance of a damaged assembly. The assembly has been designed according to Eurocode 5. Two different initial conditions have been tested. For the first assembly, the columns and the beam have been dried before machining and tested dry. For the second assembly, the beam was wet and the columns were dry before machining, then the assembly was tested dry. The difference of moisture content implies a huge tensile strain in the direction perpendicular to the grain of the columns before loading. In order to qualify the assembly behavior, strain gauges techniques have been used. This analysis allows a better understanding of the phenomenon of cracks initiation and propagation due to the coupled effect of shrinkage/swelling and loading.
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Determination of the Moisture Change Behavior of Cross-Laminated Timber Using an Optical Flow Based Computer Vision Technique

https://research.thinkwood.com/en/permalink/catalogue2229
Year of Publication
2019
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Hofinger, Markus
Pock, Thomas
Moosbrugger, Thomas
Organization
Graz University of Technology
Publisher
Taylor&Francis Online
Year of Publication
2019
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Moisture
Keywords
Deformation
Swelling
Shrinkage
Research Status
Complete
Series
Wood Material Science & Engineering
Summary
Although cross-laminated timber (CLT) offers greatly improved directional stability against moisture changes compared to lumber, some layup dependent directional differences still remain. Furthermore, even under a purely homogeneous distributed moisture change strong deformations appear along the boundaries, which show a decrease of swelling/shrinkage towards the inside of CLT panels. Metrological determination of this behavior is still a challenging task and involves long-lasting moisture content conditioning and typically manual measurements. This limits the amount of measurable data-points and thus the gain-able insights. We apply a recently introduced computer vision technique based on optical flow from scan images to measure surface deformation fields of various CLT specimens with different layups. This allows us to measure the change of average differential swelling and shrinkage coefficients throughout the cross section and visualize them as curves with high resolution. We gain measurements for each image pixel and demonstrate good matching to previously published manual single-point measurements. Furthermore, we analyze various specimens specifically built to allow for investigations of the aforementioned boundary effects. Using the computer vision approach we are able to show how the combination of homogeneous deformations and boundary effects leads to the resulting deformations observable with manual methods.
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146 records – page 2 of 15.