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35 records – page 1 of 4.

Effects of Component Ratio of the Face and Core Laminae on Static Bending Strenght Performance of Three-Ply Cross-Laminated Wood Panels with Sugi (Cryptomeria Japonica)

https://research.thinkwood.com/en/permalink/catalogue1468
Year of Publication
2006
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Park, Han-Min
Fushitani, Masami
Publisher
Society of Wood Science and Technology
Year of Publication
2006
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Sugi
Lamina Thickness
Modulus of Elasticity
Modulus of Rupture
Proportional Limit Stress
Bending Strength
Research Status
Complete
Series
Wood and Fiber Science
Summary
In order to improve the bending strength performance of three-ply laminated wood panels and use them as construction-grade panel materials, twelve types of three-ply cross-laminated wood panels whose percentages of core lamina thickness versus total lamina thickness were 33%, 50%, and 80% were made with sugi (Japanese cedar), and the effect of component ratio of the face and core laminae on their static bending strength performance was investigated. The moduli of elasticity (MOE), proportional limit stresses and moduli of rupture (MOR), perpendicular (C type) and parallel (C type) to the grain of face laminae markedly increased or decreased with increasing percentage of core lamina thickness. The percentages of core lamina thickness at which each strength property value of C type became equal to that of C type ranged from 65% to 80%. At each percentage of core lamina thickness, the MOE and proportional limit stress of C type were higher in C (45) specimens having perpendicular-direction lamina of 45° annual ring angle in the core than in C (90) specimens having perpendicular-direction lamina of 90° in the core, whereas there was little difference in MOR between C (45) specimens and C (90) specimens. For 45° specimens having the core lamina thickness from 60% to 70%, MOE as well as MOR parallel and perpendicular to the grain of face laminae exceeded the corresponding requirement values of structural plywood with 21.0-mm thickness specified in Japanese Agricultural Standards.
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Proposal of Reinforcing Method Using Wooden Sheets for Reduction of Strength Variation Coefficient of Glued Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1145
Year of Publication
2012
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Mori, Takuro
Adachi, Koji
Umemura, Kenji
Yamauchi, Hidefumi
Yano, Hiroyuki
Publisher
J-STAGE
Year of Publication
2012
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bending Strength
Reinforcement
Bending Test
Strength Distribution
Defects
Research Status
Complete
Series
Journal of the Society of Materials Science, Japan
Summary
Glued laminated timber (glulam) composed of mechanical-graded lamina shows higher strength reliability than lumber. However the glulam still has wider strength distribution than steel or concrete for structural applications because of the large difference between the mean and the lower limit value. This study aimed at reduction of the coefficient of variation of the glulam in bending strength by partial reinforcement technique using wooden sheets. The wooden sheets made from bamboo or white oak were covered to several defects on the surface of glulam such as large knots and finger joints. The strength performance and the reinforcement effect for the bending test of the glulam with reinforcement materials were evaluated. As a result, it was clarified that a bamboo sheet (two layers) or a white oak sliced veneer sheet could reinforce the defects, and the average of bending strength was improved due to the improvement in the lower value in the strength distribution.
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Performance Evaluation of Phenol Formaldehyde Resin-Impregnated Veneers and Lamminated Veneer Lumber

https://research.thinkwood.com/en/permalink/catalogue1444
Year of Publication
2012
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Wang, Brad
Chui, Ying Hei
Publisher
Society of Wood Science and Technology
Year of Publication
2012
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Mountain Pine Beetle
Lodgepole Pine
Resin Impregnation
Modulus of Elasticity
Phenol Formaldehyde
Dimensional Stability
Hardness
Bending Strength
Bending Modulus
Shear Strength
Research Status
Complete
Series
Wood and Fiber Science
Summary
For the past decade, mountain pine beetle infestation in British Columbia, Canada, has substantially changed wood characteristics of vast amounts of the lodgepole pine (Pinus contorta) resource. Resin impregnation is one method that could improve the properties of the beetle-affected wood. The key objective of this study was to examine the impact of resin impregnation on dynamic MOE of lodgepole pine veneers and properties of laminated veneer lumber (LVL) made with these treated veneers. A new phenol formaldehyde resin was formulated to treat these veneers using dipping and vacuum-pressure methods. Five-ply LVL billets were made with treated and untreated veneers. Their color, dimensional stability, surface hardness, flatwise bending modulus and strength, and shear strength were evaluated. Good correlation existed between veneer MOE enhancement and resin solids uptake. With the same treatment, stained veneers had higher resin retention and in turn greater MOE enhancement than nonstained (clear) veneers. A 5-min dipping was sufficient for veneers to achieve approximately 7 and 10% resin solids uptake and in turn 5 and 8% enhancement in veneer MOE for nonstained and stained veneers, respectively. LVL made with treated veneers had a harder surface with no discoloration concerns compared with the control. Also, evidence suggested that use of resin impregnation can improve dimensional stability, shear strength, and flatwise bending MOE of LVL.
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Cross Laminated Timber – Properties and Use for Building Purposes: A Review from the Experience of Swiss Researchers

https://research.thinkwood.com/en/permalink/catalogue23
Year of Publication
2013
Topic
Mechanical Properties
General Information
Material
CLT (Cross-Laminated Timber)
Author
Niemz, Peter
Sonderegger, Walter
Publisher
Transilvania University Press Brasov
Year of Publication
2013
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
General Information
Keywords
Physical Properties
MOE
Bending Strength
Building Applications
Research Status
Complete
Series
Pro Ligno
Summary
An overview on the mechanical and physical properties of cross laminated timber (solid wood panels) in the building industry and its use in timber construction is presented. Structure-property relations for solid wood based materials are discussed. Important properties, such as strength, sorption, diffusion, thermal conductivity in relation to the board structure are presented. By varying the structure, the properties can be optimized over a wide range. The focus of this publication lies on experimental works performed by Swiss researchers at the ETH Zürich.
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Bending Tests on Glued Laminated Timber Beams with Well-Known Material Properties

https://research.thinkwood.com/en/permalink/catalogue186
Year of Publication
2013
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Fink, Gerhard
Kohler, Jochen
Frangi, Andrea
Organization
ETH Zurich
Year of Publication
2013
Format
Report
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Bending Strength
Failure
Load Bearing Capacity
Four Point Bending Test
Density
Model
Bending Stiffness
Research Status
Complete
Summary
At the Institute of Structural Engineering at the ETH Zurich numerous of investigations are conducted to analyse the load bearing capacity of glued laminated timber beams. The investigations are part of the research project ’Influence of varying material properties on the load bearing capacity of glued laminated timber (glulam)’. The investigations are taking place on 24 glulam beams with well-known material properties. The glulam beams are fabricated out of 400 timber boards. From those boards the material properties are investigated non-destructively within a former research project. During the glulam fabrication it is particularly focused to keep the information of the timber boards; i.e. after the glulam fabrication the position of each particular timber board within the glulam beam and thus the position of each particular knot is still known. The glulam beams are investigated during a 4-point bending test. On the glulam members the load bearing capacity, the bending stiffness and the density is measured. Furthermore local strains within the glulam beams are investigated using an optical coordinate-measurement device. Following the test the failure is investigated in detail. Hereby the type of failure (knot cluster, finger joint, clear wood) and the amount of failure (number of damaged lamellas) is documented. Afterwards the failed glulam beams are loaded again to analyse the remaining bending strength and the corresponding remaining bending stiffness. The major aim of the experimental analysis is the investigation of the load bearing capacity of glulam beams with well-known local material properties. The gained results can be used for an investigation of the influence of local weak zones, such as knot clusters or finger joints, on the load bearing capacity of glulam. In addition a data basis is produced to develop a new model (or to evaluate existing models) for the estimation of the load bearing capacity of glulam.
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Strength Properties of CLT Composed of Sugi Laminations: (5) In-Plane Bending Strength

https://research.thinkwood.com/en/permalink/catalogue987
Year of Publication
2013
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Hiramatsu, Yasushi
Miyattaki, Atsushi
Shinto, Kenta
Watanabe, Hiroshi
Organization
Architectural Institute of Japan
Year of Publication
2013
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bending Strength
Sugi
Research Status
Complete
Summary
Cross-laminated timber (CLT) has recently emerged as a new wood product that utilizes a large quantity of domestic lumber. This study aims to analyze the effects of width and lay-ups on the tensile strength of CLT. To this end, the elastic modulus of sugi CLT with different lay-ups was measured by dynamic and static methods. Moreover, tensile tests were conducted for different widths and lay-ups of CLT. Results indicate that the apparent bending Young’s modulus, as calculated using the dynamic method, is directly proportional to the measured Young’s modulus in static method for each lay-up. Furthermore, there was no significant effect of width on the tensile strength in the range of 150, 300, and 600 mm. However, the variations in lay-ups affected the tensile strength as follows: CLT with larger ratio of the major strength direction lamina along the cross-section and with higher grade of lamina in the major strength direction showed higher tensile strength. The estimated tensile strength of CLT, as calculated using the Young’s modulus of the lamina of each layer, and the tensile strength of lamina as simple substance was found to be in good agreement with the measured tensile strength of CLT.
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Bending Strength of Cross Laminated Timber Beams Loaded In Plane

https://research.thinkwood.com/en/permalink/catalogue28
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Beams
Author
Blaß, Hans Joachim
Flaig, Marcus
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Bending Strength
Monte Carlo Model
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
A computer aided numerical model for the simulation of the in-plane bending strength of CLT beams is presented. The model uses the Monte-Carlo-Method to generate mechanical characteristics of board lamellae and is suitable for the investigation of statistical effects such as homogenisation and size effects. Six different types of CLT beams, varying in size and in layup, were tested to validate the model and except for beams with only one lamella in direction of the beam height good agreement was found between the experimental results and the model’s simulations.
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Identification of Weak Sections in Glulam Beams using Calculated Stiffness Profiles based on Lamination Surface Scanning

https://research.thinkwood.com/en/permalink/catalogue196
Year of Publication
2014
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Oscarsson, Jan
Serrano, Erik
Olsson, Anders
Enquist, Bertil
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Bending Strength
Failure
Modulus of Elasticity
Laser Scanning
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
Models for estimation of structural properties of glued laminated timber (glulam) are generally based on the relationship between properties of the individual laminations and properties of the glulam. In this investigation, a recently presented machine strength grading method based on laser scanning of fibre direction fields was applied for determination of axial modulus of elasticity (MOE) profiles along glulam laminations. These profiles were then used to calculate edgewise bending MOE (EB) profiles of glulam beams. The objectives were to investigate the relationship between position of bending failure and position of lowest EB value along investigated beams, and the relationship between the mentioned EB value and bending strength of the beams. It was found that both relationships were rather weak, whereas local bending MOE determined in accordance with EN 408 was predicted with high accuracy on the basis of EB profiles.
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Experimental Behaviour of Structural Size Glued Laminated Guadua Bamboo Members

https://research.thinkwood.com/en/permalink/catalogue528
Year of Publication
2014
Topic
Mechanical Properties
Material
Other Materials
Application
Beams
Columns
Author
Correal, Juan
Echeverry, Juan
Yamin, Luis
Ramírez, Fernando
Year of Publication
2014
Format
Conference Paper
Material
Other Materials
Application
Beams
Columns
Topic
Mechanical Properties
Keywords
Bending Strength
Flexural Tests
Compression Tests
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
This study presents the experimental evaluation of the behaviour of beams and columns made of Glued Laminated Guadua (GLG) bamboo. Flexural tests were conducted on structural size beams of various span lengths and two lamination orientations (horizontal and vertical) in order to evaluate the different capacities achieved according to the predominant induced stresses, bending or shear. Experimental results indicated a reduction of bending strength as the member’s size increased whereas lamination in the vertical direction presented 12% higher values of modulus of rupture (MOR), and 9% higher values of modulus of elasticity (MOE) compared to equivalent results for lamination in the horizontal direction. Additionally, compression tests were performed on structural size columns with various slenderness ratios and two lamination orientations. Although minor differences were found for lamination orientation, lower capacities were observed as the slenderness ratio increased. This experimental data is expected to be used in order to propose adjustment factors for structural size beams as well as the determination of the column stability factor.
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Estimation of Bending Stiffness, Moment Carrying Capacity and Internal Shear Force of Sugi CLT Panel

https://research.thinkwood.com/en/permalink/catalogue622
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Okabe, Minoru
Yasumura, Motoi
Kobayashi, Kenji
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Keywords
Internal Shear Strength
Bending Strength
Moment Carrying Capacity
Monte Carlo
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
CLT panels consist of several layers of lumber stacked crosswise and glued together on their faces. Prototype Sugi CLT floor panels were manufactured and bending and internal shear tests were carried out under the different parameters of lumber MOE, number of layers, thickness of lumber and thickness of CLT panels. On the basis of above tests, internal shear strength, bending stiffness and moment carrying capacity were estimated based on the lumber properties by Monte Carlo method. Bending stiffness EI of CLT panels could be estimated by adopting parallel layer theory and equivalent section area. Experimental moment carrying capacity showed 12% higher value than the calculated moment carrying capacity by average lumber failure method, and also showed 45% higher value than the calculated moment carrying capacity by minimum lumber failure method due to the reinforcement of the outer layer by the neighboring cross layer. Experimental internal shear force of CLT panel showed 30% higher value than the calculated one.
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35 records – page 1 of 4.