Skip header and navigation

13 records – page 1 of 2.

Bamboo/Wood Composites and Structures Shear and Normal Strain Distributions in Multilayer Composite Laminated Panels under Out-of-Plane Bending

https://research.thinkwood.com/en/permalink/catalogue2769
Year of Publication
2021
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Niederwestberg, Jan
Zhou, Jianhui
Chui, Ying Hei
Huang, Dongsheng
Publisher
Hindawi Publishing Corporation
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Three Point Bending Test
Shear Test
Digital Image Correlation
Strain
Shear Analogy
Finite Element Modelling
Stress
Language
English
Research Status
Complete
Series
Advances in Civil Engineering
Summary
Innovative mass timber panels, known as composite laminated panels (CLP), have been developed using lumber and laminated strand lumber (LSL) laminates. In this study, strain distributions of various 5-layer CLP and cross-laminated timber (CLT) were investigated by experimental and two modelling methods. Seven (7) different panel types were tested in third-point bending and short-span shear tests. During the tests, the digital imaging correlation (DIC) technique was used to measure the normal and shear strain in areas of interest. Evaluated component properties were used to determine strain distributions based on the shear analogy method and finite element (FE) modelling. The calculated theoretical strain distributions were compared with the DIC test results to evaluate the validity of strain distributions predicted by the analytical model (shear analogy) and numerical model (FE analysis). In addition, the influence of the test setup on the shear strain distribution was investigated. Results showed that the DIC strain distributions agreed well with the ones calculated by the shear analogy method and FE analysis. Both theoretical methods agree well with the test results in terms of strain distribution shape and magnitude. While the shear analogy method shows limitations when it comes to local strain close to the supports or gaps, the FE analysis reflects these strain shifts well. The findings support that the shear analogy is generally applicable for the stress and strain determination of CLP and CLT for structural design, while an FE analysis can be beneficial when it comes to the evaluation of localized stresses and strains. Due to the influence of compression at a support, the shear strain distribution near the support location is not symmetric. This is confirmed by the FE method.
Online Access
Free
Resource Link
Less detail

Bending and Rolling Shear Capacities of Southern Pine Cross Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue1596
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Gu, Mengzhe
Pang, Weichiang
Stoner, Michael
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Southern Pine
US
Manufacturing
Rolling Shear
Bending
Three Point Bending Test
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1899-1906
Summary
Southern Pine (SP) is one of the fastest growing softwood species in the Southern Forest of United States. With its high strength to weight ratio, SP becomes an ideal candidate for manufacturing engineered wood products such as cross laminated timber (CLT). Two batches of CLT panels were manufactured using visually graded SP lumbers in this study: pilot-scale panels in a laboratory setting and full-size panels in a manufacturing plant environment. The first batch of pilot-scale CLT panels was manufactured at Clemson University. The second batch of full-scale CLT panels (3m x 12.2m) was produced and CNC-sized by Structurlam in Penticton, Canada and shipped to Clemson University for testing. Four types of structural wood adhesives were selected in the panel production, namely Melamine Formaldehyde (MF), Phenol Resorcinol Formaldehyde (PRF), Polyurethane (PUR) and Emulsion Polymer Isocyanate (EPI). This paper presents the manufacturing process of SP CLT in a laboratory setting as well as structural performance verification of 3- ply SP CLT in terms of rolling shear and bending properties. The obtained performance data of 3-ply CLT in both major and minor strength directions is verified against PRG-320 Standard for Performance Rated Cross Laminated Timber. Tested results are presented and discussed.
Online Access
Free
Resource Link
Less detail

Bending Properties of Innovative Multi-Layer Composite Laminated Panels

https://research.thinkwood.com/en/permalink/catalogue1985
Year of Publication
2018
Topic
Mechanical Properties
Material
LSL (Laminated Strand Lumber)
OSL (Oriented Strand Lumber)
Application
Beams

Effect of Knots and Slope of Grains on the Rolling Shear in Dimensional Timber Used in CLT Core Layers

https://research.thinkwood.com/en/permalink/catalogue1541
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Beams
Author
Grandvuinet, Thibault
Muszynski, Lech
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Knots
Transverse Core Layer
Three Point Bending Test
Rolling Shear
MOR
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1099-1104
Summary
The cross-laminated timber (CLT) technology is also perceived as a potential for utilization of lumber oflower grades and underused species, because the core layers perpendicular to the principle loading direction transferloads through rolling shear, which is not correlated to the grade of lumber. Current the product standard however specifies the minimum grade requirements for all lumber to be used as CLT laminations. In this study the effect of the presence of knots in the transverse core layer of CLT billets was examined in matched CLT samples where the heavy presence of knots in the transverse core layer was the only variable compared to knot free reference. All samples were tested as short-beams in three point bending and all failed in rolling shear in the transverse core layer. The presence of knots had no measurable effect on the shear capacity expressed as nominal MOR of the tested CLT beam samples
Online Access
Free
Resource Link
Less detail

Evaluating Rolling Shear Strength Properties of Cross-Laminated Timber by Short-Span Bending Tests and Modified Planar Shear Tests

https://research.thinkwood.com/en/permalink/catalogue1403
Year of Publication
2017
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Minghao
Publisher
Springer Japan
Year of Publication
2017
Country of Publication
Japan
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Rolling Shear Strength
Non-Edge-Glued
Pine
Thickness
Three Point Bending Test
Planar Shear Tests
Europe
Canada
Language
English
Research Status
Complete
Series
Journal of Wood Science
ISSN
1611-4663
Summary
This paper presents an experimental study on rolling shear (RS) strength properties of non-edge-glued cross-laminated timber (CLT) made out of New Zealand Radiata pine (Pinus radiata) structural timber. CLT specimens with 35 and 20 mm thick laminations were studied to evaluate the influence of lamination thickness on the RS strength of CLT. Short-span three-point bending tests were used to introduce high RS stresses in cross layers of CLT specimens and facilitate the RS failure mechanism. Modified planar shear tests from the conventional two-plate planar shear tests were also used to evaluate the RS strength properties. It was found that two test methods yielded comparable RS strength properties and the lamination thickness significantly affected RS strength of the CLT specimens. The test results also indicated that the recommended characteristic RS strength values of CLT products in Europe and Canada might be over conservative. Also, it might be more efficient to specify different RS strength values for CLT with different lamination thickness given the minimum width-to-depth ratio of laminations is satisfied.
Online Access
Free
Resource Link
Less detail

Influence of Layer Arrangement on Bonding and Bending Performances of Cross-laminated Timber Using Two Different Species

https://research.thinkwood.com/en/permalink/catalogue2591
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Kim, Keon-Ho
Publisher
North Carolina State University
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Design and Systems
Mechanical Properties
Keywords
Bonding Performance
Bending Performance
Shear Walls
Face Bonding Test
Three-Point Bending Test
Japanese Larch
Korean Red Pine
Language
English
Research Status
Complete
Series
BioResources
Summary
Cross-laminated timber (CLT) is a wood panel product that can be arranged in different ways. The advantage of utilizing CLT is the ability to use lamination even with low density materials or those that have defects, like knots. This study evaluated the bonding and bending performances of CLT utilizing domestic species in a shear wall or floor via a face bonding test of layers and a three-point bending test. The tests were carried out with three-layered CLT made up of Japanese larch and/or Korean red pine in various configurations. The layer arrangement for lamination was divided according to the species and grade of the wood. The out-of-plane and in-plane bending tests were conducted on the CLT according to the applicable direction in a wooden structure. The results of the bonding test showed that the block shear strength and delamination of all types of CLT met the BS EN 16351 (2015) standard requirements. The results of the bending test based on two wood species showed that the bending strength of the larch CLT was higher than that of the pine CLT in single species combinations. For mixed species combinations, the bending properties of CLT using larch as the major layer was higher than those using pine as the major layer. This demonstrated that the major layer had more influence on the bending properties of CLT and that Korean red pine was more suited for the minor layer of CLT.
Online Access
Free
Resource Link
Less detail

Material Characteristics and Bending Performance of Glued Laminated Timber Made of Local Lumbers

https://research.thinkwood.com/en/permalink/catalogue2438
Year of Publication
2019
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Beams

Measurement of Rolling Shear Modulus of Cross Laminated Timber: Exploratory Study Using Downscaled Specimens Under Variable Span Bending Tests

https://research.thinkwood.com/en/permalink/catalogue605
Year of Publication
2012
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Zhou, Qinyi
Gong, Meng
Chui, Ying Hei
Mohammand, Mohammand
Publisher
IEEE
Year of Publication
2012
Country of Publication
China
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Rolling Shear Modulus
Three Point Bending Test
Steel
Span-to-Depth Ratio
Growth Ring Orientation
Language
English
Conference
International Conference on Biobase Material Science and Engineering
Research Status
Complete
Notes
October 21-23, 2012, Changsha, China
Summary
The purpose of this study was to measure the rolling shear modulus of Cross Laminated Timber (CLT), which was achieved by conducting 3-point bending tests with variable span using downscaled sandwich specimens. Two types of sandwich specimens were employed: steel-wood-steel (SWS) and wood-wood-wood (WWW). Experimental results from SWS specimens were verified with those predicted from WWW ones through the shear analogy method. Effects of span-to-depth ratio (l/h) and growth ring orientation on rolling shear modulus (G RT ) were also examined. It was found that the average deflection of WWW specimens tested at l/h of 6.5 could be well predicted using the shear analogy method based on true elasticity of modulus (E m ) and G RT of the cross layer measured using SWS specimens under variable span tests. The results also showed that the cross layer of `in-between' growth ring orientation could gain the higher rolling shear modulus than that of flat sawn or quarter sawn one.
Online Access
Payment Required
Resource Link
Less detail

Overstrength of Dowelled CLT Connections Under Monotonic and Cyclic Loading

https://research.thinkwood.com/en/permalink/catalogue1385
Year of Publication
2018
Topic
Connections
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Author
Ottenhaus, Lisa-Mareike
Li, Minghao
Smith, Tobias
Quenneville, Pierre
Publisher
Springer Netherlands
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Seismic
Keywords
Overstrength
Ductility
Three Point Bending Test
Fasteners
Yield Moment
Monotonic Loading
Cyclic Loading
Steel Dowels
Steel Plates
Language
English
Research Status
Complete
Series
Bulletin of Earthquake Engineering
ISSN
1573-1456
Summary
This paper presents an evaluation of overstrength based on an experimental study on dowelled connections in cross-laminated timber (CLT). Connection overstrength needs to be well understood in order to ensure that ductile system behaviour and energy dissipation can be achieved under seismic loading. Overstrength is defined as the difference between the code-based strength, using characteristic material strengths, and the 95th 4 percentile of the true strength distribution. Many aspects contribute to total connection overstrength, which makes its definition challenging. In this study, half-hole embedment tests were performed on CLT to establish embedment strength properties and three point bending tests were performed to determine the fastener yield moment. Different connection layouts, making use of mild steel dowels and an internal steel plate, were tested under monotonic and cyclic loading to evaluate theoretically determined overstrength values and study the influence of cyclic loading on overstrength. Experimental results were compared with strength predictions from code provisions and analytical models for ductile response under monotonic loading. It was found that cyclic loading does not significantly influence overstrength for connections that respond in a mixed-mode ductile way indicating that in future more expedient monotonic test campaigns could be used. This work also provides further experimental data and theoretical considerations necessary for the estimation of a generally applicable overstrength factor for dowelled CLT connections.
Online Access
Free
Resource Link
Less detail

Shear Resistance of Glulam Beams with Cracks

https://research.thinkwood.com/en/permalink/catalogue997
Year of Publication
2012
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Pousette, Anna
Ekevad, Mats
Year of Publication
2012
Country of Publication
Sweden
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Cracks
Shear Strength
Three Point Bending Test
Language
English
Conference
CIB-W18 Meeting
Research Status
Complete
Notes
August 27-30, 2012, Växjö, Sweden p. 257-265
Summary
A reduction of the shear resistance was introduced with the crack factor kcr in Eurocode 5. The factor 0.67 corresponds to cracks that have a depth of 1/3 of the beam width. The aim of this project was to learn more about different types of cracks and their importance for the shear strength of glulam beams. The project started with tests of five types of glulam beams, with or without cracks. The cracks had different depths and locations, three beam types had cracks made by sawing and one type had cracks from moisturing and drying. The beam dimensions were 115 mm x 315 mm x 2600 mm. Five beams of each type with cracks were tested and ten beams without cracks. The beams were Swedish standard beams made of Spruce and taken from the normal production. Three-point bending method was used for the shear tests. The beams of type 1 without cracks got mostly bending failures; the characteristic shear strength was at least 3.5 MPa. Beams with sawn grooves got lower characteristic shear values and this means a reduced cross section should be used for beams with cut grooves along the beams. Beams with drying cracks got more shear failures, but the characteristic shear strength of the beams was about the same as for beams without cracks.
Online Access
Free
Resource Link
Less detail

13 records – page 1 of 2.