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11 records – page 1 of 2.

CLT Panels Subjected to Combined Out-of-Plane Bending and Compressive Axial Loads

https://research.thinkwood.com/en/permalink/catalogue1729
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Wang, Jasmine
Mohammad, Mohammad
Di Lenardo, Bruno
Sultan, Mohamed
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Out Of Plane
Bending
Compressive Axial Loads
Canada
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4738-4745
Summary
With the introduction of Cross Laminated Timber (CLT) into North America and gaining popularity it is of interest to the design and code development community to have codified provisions to facilitate the design of CLT structures. This paper addresses the design aspect of CLT panels subjected to combined bending and compressive axial loads. Fifteen specimens covering different combinations of grades and layups of commercially available Canadian CLT panels were tested at different eccentricities to validate the proposed interaction equation. Testing program was reported in this paper and the test data was compared with the model prediction. It was concluded that the current nonlinear interaction equation given in the Canadian timber design standard (CSA O86) for timber and glulam tends to overestimate the capacity of CLT wall panel. A linear interaction equation was found to be appropriate
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Comparison of Theoretical and Laboratory Out-of-Plane Shear Stiffness Values of Cross Laminated Timber Panels

https://research.thinkwood.com/en/permalink/catalogue2177
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)

Compressive Strength Properties Perpendicular to the Grain of Larch Cross-laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2410
Year of Publication
2019
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems

Finite Element Analysis of Bending Stiffness for Cross-Laminated Timber with Varying Board Width

https://research.thinkwood.com/en/permalink/catalogue2455
Year of Publication
2019
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Berg, Sven
Turesson, Jonas
Ekevad, Mats
Huber, Johannes
Organization
Luleå University of Technolog
Publisher
Taylor&Francis Online
Year of Publication
2019
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Finite Element Analysis
Board Width
Out-of-Plane Load
Research Status
Complete
Series
Wood Material Science & Engineering
Summary
Cross laminated timber (CLT) is a wood panelling building system that is used in construction, e.g. for floors, walls and beams. Because of the increased use of CLT, it is important to have accurate simulation models. CLT systems are simulated with one-dimensional and two-dimensional (2D) methods because they are fast and deliver practical results. However, because non-edge-glued panels cannot be modelled under 2D, these results may differ from more accurate calculations in three dimensions (3D). In this investigation, CLT panels with different width-to-thickness ratios for the boards have been simulated using the finite element method. The size of the CLT-panels was 3.0 m × 3.9 m and they had three and five laminate layers oriented 0°–90°–0° and 0°–90°–0°–90°–0°. The thicknesses of the boards were 33.33, 40.0, and 46.5 mm. The CLT panel deformation was compared by using a distributed out-of-plane load. Results showed that panels with narrow boards were less stiff than wide boards for the four-sided support setup. The results also showed that 2D models underestimate the displacement when compared to 3D models. By adjusting the stiffness factor k88, the 2D model displacement became more comparable to the 3D model.
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Long-term bending properties of cross-laminated timber made from Japanese larch under constant environment

https://research.thinkwood.com/en/permalink/catalogue3027
Year of Publication
2021
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Takanashi, Ryuya
Ohashi, Yoshinori
Ishihara, Wataru
Matsumoto, Kazushige
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Creep
Creep Rupture
Duration of Load
Out-of-plane Bending
Survival Analysis
Research Status
Complete
Series
Journal of Wood Science
Summary
Cross-laminated timber (CLT) has been used extensively in timber construction. CLT panels are typically used in roofs and floors that carry a continuous load, and it is important to examine the long-term loading capacity of CLT. However, studies that focus on the long-term loading capacity of CLT are limited. To this end, we conducted long-term out-of-plane bending tests on seven-layer CLT made from Japanese larch (Larix kaempferi) under constant environmental conditions, investigated creep performance and duration of load, and experimentally analyzed creep rupture behavior. The mean estimated relative creep after 50 years was 1.49. The sample showed a satisfactory resistance to creep as a building material. The duration of load of most of the specimens in this study was shorter than the conventional value of small clear wood specimens. Specimens had a lower duration of load capacity than solid lumber. According to the results of survival analysis, a loading level of 70% or more caused the initial failure of specimens. Creep rupture of most of the specimens occurred at less deflection than displacement at failure in the short-term loading test. Additional studies focusing on the effects of finger joints, transverse layers, and width of a specimen on creep rupture behavior are suggested.
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Long-term Out-of-Plane Testing of Timber Floors Strengthened with Innovative Timber-to-Timber Solutions

https://research.thinkwood.com/en/permalink/catalogue1740
Year of Publication
2016
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Giongo, Ivan
Schiro, Gianni
Piazza, Maurizio
Tomasi, Roberto
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Serviceability
Keywords
Long-term
Out Of Plane
Spruce
Screws
Uniformly Distributed Load
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4854-4861
Summary
The outcome of an experimental campaign on the long-term behaviour of timber floors retrofitted with timber-to-timber composite methods is presented. Four diaphragm specimens, 5.2 m long (5 m span) were tested out-ofplane. Each specimen consisted of a solid wood-spruce joist strengthened with a crosslam panel. A layer of timber boards was placed in between the joist and the panel to simulate the existing flooring. The specimens, were subjected to uniformly distributed loading in a climatic controlled chamber. A patented procedure that enables to apply a pre-stressed state and a pre-camber to the composite floor joists by just using screw fasteners, was adopted. Different typologies and arrangements of screws were tested in order to maximize the performance (cost/effectiveness) that can be achieved by employing the above mentioned procedure. Uplift values of approximately 1/300th of the diaphragm span were registered at the end of the cambering procedure. After an initial testing phase (duration approximately equal to 3h) where the loading was consistent with the characteristic combination, the specimens were set for long-term testing under an imposed load equal to that specified by the quasi-permanent combination.
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Mechanical Properties of Cross-laminated Timber (CLT) Panels Composed of Treated Dimensional Lumber

https://research.thinkwood.com/en/permalink/catalogue2423
Year of Publication
2019
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Floors

Out-of-Plane Tensile Properties of Cross Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue2940
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Author
Brandner, Reinhard
Jantscher, Lukas
Organization
Graz University of Technology
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Mechanical Properties
Keywords
Out-Of-Plane Tension
Size Effect
System Effects
Modulus of Elasticity
Strength
Equicorrelation
Research Status
Complete
Series
Buildings
Summary
A systematic investigation is still lacking for tension out-of-plane in cross laminated timber (CLT), as a planar timber construction product. The objectives of the present study are the determination of the tensile properties of CLT made of Norway spruce, the identification of essential product-specific influencing parameters and a comparative analysis with glulam. For this purpose, seven test series were defined, which allowed the determination of the tensile properties on board segments and thereof produced glulam and CLT specimens by varying the number of layers, layer orientation and number of elements within a layer. The orthogonal laminated structure of CLT led to between 50% and 70% higher tensile properties out-of-plane, which is explained by the different stress distribution compared to glulam; the regulation of 30% higher properties than for glulam is suggested. In addition, the lognormal distribution turned out to be a more representative distribution model for characterizing the tensile strength out-of-plane than the Weibull distribution. This was also confirmed with regard to the investigated serial and parallel system effects, in which a clearly more homogeneous behavior was found in CLT compared to glulam, which in turn can be attributed again to the different stress distributions.
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Free
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Performance of Cross-Laminated Timber as a Residential Building Material Subject to Tornado Events

https://research.thinkwood.com/en/permalink/catalogue2523
Year of Publication
2020
Topic
Wind
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems

Process Modeling for CLTs using SDT Feedstock

https://research.thinkwood.com/en/permalink/catalogue2676
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Organization
Washington State University
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Small Diameter
Out Of Plane
Lumber Grade
Douglas-Fir
Ponderosa Pine
Research Status
In Progress
Notes
Project contact is Karl Englund at Washington State University
Summary
Cross laminated timber (CLT) has energized the wood industry, not only throughout the US but also across the globe. Potential for lower construction costs and a sustainable building material has provided proponents of CLTs the fuel for their growth. However, to obtain lower feedstock costs and provide a truly sustainable building product the use of small diameter timber (SDT) and other lower quality woods is imperative, but not yet realized. The out-of-plane (OOP) defects such as twist, cup and bow commonly found in SDTs, make processing CLTs prohibitive due to the press load requirements that are needed to “flatten” these defects out and create intimate contact at the glue line. Due to this issue, many CLT manufacturers utilize high grade lumber, while SDT and other low value woods are culled out and not used. Our proposal will characterize the OOP defects commonly found in SDT Douglas-fir (DF) and ponderosa pine (PP) from the Inland Northwest, will develop a tool to calculate anticipated forces to compress out the OOP defects and evaluate the durability performance of a full-scale CLT panel that includes commonly rejected lumber from SDT due to presence of OOP defects. The tool developed in this project will provide the CLT industry with the know-how to determine the press loads required to make a panel from SDT feedstocks and how to lower these accumulated loads through reducing or changing the laminate cross-sectional dimensions. Results of this study will promote increased utilization of SDT lumber, currently rejected, for CLT production and will contribute to healthy forests and rural economic development.
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11 records – page 1 of 2.