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17 records – page 1 of 2.

The Applicability of I-214 Hybrid Poplar as Cross-Laminated Timber Raw Material

https://research.thinkwood.com/en/permalink/catalogue1132
Year of Publication
2015
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Markó, Gábor
Bejó, László
Takáts, Péter
Year of Publication
2015
Country of Publication
Hungary
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Poplar
Bending Test
Polyurethane
MOE
Low-Grade
Language
Hungarian
Research Status
Complete
Series
Faipar
ISSN
2064-9231
Summary
Cross-Laminated Timber (CLT) is a relatively new construction material that has not gained popularity in Hungary yet. Producing such building elements using Hungarian raw materials may help to establish this technique. The purpose of our research was to examine the possibility of producing CLT using Hungarian I-214 hybrid poplar. One three-layer panel was produced using Hungarian hybrid polar and polyurethane resin, and tested in bending. The MOR of the poplar CLT was found to be comparable to low-grade softwood CLT, but the MOE was lower than the requirement. Poplar raw material may be suitable for CLT production by selecting higher grade raw material using nondestructive testing, or as a secondary raw material mixed in with softwood.
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Cross-Laminated Timber Engineering: Improvement and Application

https://research.thinkwood.com/en/permalink/catalogue1366
Year of Publication
2014
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Kramer, Anthonie
Organization
Oregon State University
Year of Publication
2014
Country of Publication
United States
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Poplar
Energy Dissipation
Rocking Walls
Language
English
Research Status
Complete
Summary
The development of cross-laminated timber (CLT) panel technology has opened up new opportunities for wood in tall buildings. Several characteristics including seismic performance and speed of construction have raised interest among designers. As CLT gains acceptance in the industry, alternative structural solutions need to be investigated to improve performance of CLT as a building material. The first study presented is an assessment of the viability of hybrid poplar for use in CLT panels. Hybrid poplar is a low density species, which is not typically considered for structural applications. Low density species have the potential to improve the structural efficiency of CLT panels. The tests conducted are based on the qualification of panels outlined in the ANSI/APA PRG-320: Standard for Performance-Rated Cross-Laminated Timber to determine the structural viability of the CLT panels. The second study presented is an investigation of a new alternative energy dissipation solution to be used with cross-laminated timber rocking walls for seismic design. The energy dissipators are designed as a structural fuse which can be easily replaced after failure following a large seismic event. The results of this study give insight to alternative solutions for CLT to improve upon current applications.
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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.
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Effect of Laminated Structure Design on the Mechanical Properties of Bamboo-Wood Hybrid Laminated Veneer Lumber

https://research.thinkwood.com/en/permalink/catalogue1407
Year of Publication
2017
Topic
Mechanical Properties
Design and Systems
Material
LVL (Laminated Veneer Lumber)
Other Materials
Author
Chen, Fuming
Deng, Jianchao
Li, Xingjun
Wang, Ge
Smith, Lee
Shi, Sheldon
Publisher
Springer Berlin Heidelberg
Year of Publication
2017
Country of Publication
Germany
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Other Materials
Topic
Mechanical Properties
Design and Systems
Keywords
Bamboo
Poplar
Analytical Model
Density
MOE
MOR
Shear Strength
Glue Lines
Loading Tests
Language
English
Research Status
Complete
Series
European Journal of Wood and Wood Products
ISSN
1436-736X
Summary
The effects of veneer orientation and loading direction on the mechanical properties of bamboo-bundle/poplar veneer laminated veneer lumber (BWLVL) were investigated by a statistical analysis method. Eight types of laminated structure were designed for the BWLVL aiming to explore the feasibility of manufacturing high-performance bamboo-based composites. A specific type of bamboo species named Cizhu bamboo (Neosinocalamus affinis) with a thickness of 6 mm and diameter of 65 mm was used. The wood veneers were from fast-growing poplar tree (Populus ussuriensis Kom.) in China. The bamboo bundles were obtained by a mechanical process. They were then formed into uniform veneers using a onepiece veneer technology. Bamboo bundle and poplar veneer were immersed in water-soluble phenol formaldehyde (PF) resin with low molecular weight for 7 min and dried to MC of 8–12 % under the ambient environment. All specimens were prepared through hand lay-up using compressing molding method. The density and mechanical properties including modulus of elasticity (MOE), modulus of rupture (MOR), and shearing strength (SS) of samples were characterized under loading parallel and perpendicular to the glue line. The results indicated that as the contribution of bamboo bundle increased in laminated structure, especially laminated on the surface layers, the MOE, MOR and SS increased. A lay-up BBPBPBB (Bbamboo, P-poplar) had the highest properties due to the cooperation of bamboo bundle and poplar veneer. A higher value of MOE and MOR was found for the perpendicular loading test than that for the parallel test, while a slightly higher SS was observed parallel to the glue line compared with perpendicular loading. Any lay-up within the homogeneous group can be used to replace others for obtaining the same mechanical properties in applications. These findings suggested that the laminated structure with high stiffness laid-up on the surface layers could improve the performance of natural fiber reinforced composites.
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Evaluation of Bending Performance for Cross Laminated Timber (CLT) Made Out of Poplar (Populus Alba)

https://research.thinkwood.com/en/permalink/catalogue1218
Year of Publication
2017
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Haftkhani, Akbar
Layeghi, Mohammad
Ebrahimi, Ghanbar
Pourtahmasi, Kambiz
Publisher
Iranian Scientific Association of Wood and Paper Industries
Year of Publication
2017
Country of Publication
Islamic Republic of Iran
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Keywords
Bending Strength
Poplar
Modulus of Rupture
Modulus of Elasticity
Polyurethane
Language
Persian
Research Status
Complete
Series
Iranian Journal of Wood and Paper Industries
Summary
Bending strength is a critical property of cross laminated timber (CLT) in structural applications, especially in floor of multi-story buildings. Therefore, this study was targeted to evaluate bending strength of CLT made out of poplar (populous alba). Polyurethane adhesive was used for constructing of CLT (300 g/m2). The thickness of planks was used in this study was 16 mm. The results have indicated that modulus of rupture (MOR) and modulus of elasticity (MOE) of CLT with 45o alternating transverse layer were increased 14 and 15%, respectively in comparison with 90o layers. Also, modulus of rupture (MOR) and modulus of elasticity (MOE) of CLT consist of layers with 4cm in width were increased 14 and 5%, respectively in comparison with layers 9cm in width. The results concluded that by layers with lower width, and also 45o alternating layer configuration could be constructed CLT from fast growing trees such as poplar with a considerable bending strength.
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Experimental and Numerical Analysis of Mixed I-214 Poplar/Pinus Sylvestris Laminated Timber Subjected to Bending Loadings

https://research.thinkwood.com/en/permalink/catalogue2592
Year of Publication
2020
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Rescalvo, Francisco
Timbolmas, Cristian
Bravo, Rafael
Gallego, Antolino
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Poplar
Pine
Bending
Numerical Modelling
Non-Destructive Testing
Language
English
Research Status
Complete
Series
Materials
Summary
The structural use of timber coming from fast growing and low-grade species such as poplar is one of the current challenges in the wood value chains, through the development of engineering products. In this work, a qualitative comparison of the behavior of mixed glued laminated timber made of pine in their outer layers and of poplar in their inner layers is shown and discussed. Single-species poplar and pine laminated timber have been used as control layouts. The investigation includes destructive four-point bending tests and three non-destructive methodologies: finite elements numerical model; semi-analytical model based on the Parallel Axes theorem and acoustic resonance testing. An excellent agreement between experimental and numerical results is obtained. Although few number of samples have been tested, the results indicate that the use of poplar as a low-grade species in the inner layers of the laminated timber can be a promising technology to decrease the weight of the timber maintaining the good mechanical properties of pine. Likewise, the need for the use of the shear modulus in both experimental measurements and numerical analysis is suggested, as well as the need to reformulate the vibration methodology for non-destructive grading in the case of mixed timber.
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Feasibility of Using Poplar as Cross Layer to Fabricated Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue620
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Wang, Zhiqiang
Fu, Hongmei
Chui, Ying-hei
Gong, Meng
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bonding Strength
Shear Strength
Modulus of Elasticity
Failure Modes
Poplar
Douglas-Fir
Pine
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
Use of poplar (Populus euramericana cv. I-214) as cross layer to manufacture cross-laminated timber (CLT) was examined in this study. For comparison purpose, Douglas fir (Pseudotsuga menziesii) and Monterey pine (Pinus radiata D.Don) were used as well to produce five layups of CLT panels. The mechanical properties tested in this study included the bending strength in the major direction, modulus of elasticity in the major direction, shear strength parallel to the major direction and shear strength perpendicular to the major direction. It was found that the mechanical properties of CLT panels containing poplar were similar to those made of non-poplar wood. The major failure modes found were joint failure, shear failure and delamination. It could be feasible to use poplar as a cross layer to fabricate CLT without decreasing its strength properties.
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Highly Mechanical Performance of Laminated Veneer Lumber Induced by High Voltage Electrostatic Field

https://research.thinkwood.com/en/permalink/catalogue2148
Year of Publication
2019
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)

Laminated Strand Lumber (LSL) Reinforced by GFRP; Mechanical and Physical Properties

https://research.thinkwood.com/en/permalink/catalogue1311
Year of Publication
2018
Topic
Mechanical Properties
Design and Systems
Material
LSL (Laminated Strand Lumber)
Author
Moradpour, Payam
Pirayesh, Hamidreza
Gerami, Masood
Jouybari, Iman
Publisher
ScienceDirect
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
LSL (Laminated Strand Lumber)
Topic
Mechanical Properties
Design and Systems
Keywords
GFRP
Poplar
Modulus of Rupture
Modulus of Elasticity
Shear Strength
Compression Strength
Impact Strength
Water Absorption
Thickness Swelling
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
The effect of glass fiber reinforced polymer (GFRP) on the technical properties of LSL made from poplar (Populus deltoids L.) employing pMDI and UF as binders was investigated. Technical properties such as modulus of rupture (MOR), Modulus of elasticity (MOE), shear strength (SS), compression strength parallel to the grains (CS //), impact strength (IS), water absorption (WA) and thickness swelling (TS) were determined. Results confirmed that resin type and GFRP have significant effects on the LSL properties. It was revealed that the most beneficial effect of GFRP is on MOR, MOE, IS, SS and CS respectively. The Highest properties were obtained by using pMDI as the resin and GFRP as the reinforcement, where properties such as MOR, MOE, IS, SS and CS were improved by 123, 114, 100, 94, and 90%, respectively, compared to control samples. Furthermore, GFRP incorporation led to alteration of fracture place from tension side to compression side. Depending on the treatment type, the WA and TS values of the LVLs improved between 23% to 68% and 19.5% to 78%, respectively.
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Mechanical Performance of Yellow-Poplar Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue199
Year of Publication
2015
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Mohamadzadeh, Milad
Hindman, Daniel
Organization
Virginia Tech University
Year of Publication
2015
Country of Publication
United States
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Hardwood
Poplar
Shear Strength
Four Point Bending Test
Stiffness
Strength
Five Point Bending Test
Delamination
Language
English
Research Status
Complete
Summary
The purpose of this paper was to examine whether CLT made from fast growing hardwood species can provide sufficient mechanical performance need to be used in structural engineering applications. Yellow-poplar CLT was tested experimentally for stiffness and strength in five-point bending and four-point bending tests, respectively as well as resistance to shear by compression lading and resistance to delamination and the results were compared with American National Standard Institute/APA-The Engineered Wood Association (ANSI/APA) PRG 320-Standard for Performance Rated Cross-Laminated Timber and previous research. Bending stiffness, bending strength and resistance to delamination exceeded the required value in the standard, while wood failure in resistance to shear by compression loading was less than the required value. Shear strength of the yellow-poplar CLT was also greater than CLT produced from softwood species tested in previous research. Acceptable mechanical performance of yellow-poplar CLT confirmed in this research, could be a start point of using hardwood species in CLT structural design.
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17 records – page 1 of 2.