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49 records – page 1 of 5.

An Innovative Method Based on Grain Angle Measurement to Sort Veneer and Predict Mechanical Properties of Beech Laminated Veneer Lumber

https://research.thinkwood.com/en/permalink/catalogue1286
Year of Publication
2018
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Viguier, Joffrey
Bourgeay, Christophe
Rohumaa, Anti
Pot, Guillaume
Denaud, Louis
Publisher
ScienceDirect
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Modulus of Elasticity
Beech
Grain Angle
Grading
Density
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
Cross-Laminated Timber (CLT) structures exhibit satisfactory performance under seismic conditions. This ispossible because of the high strength-to-weight ratio and in-plane stiffness of the CLT panels, and the capacity ofconnections to resist the loads with ductile deformations and limited impairment of strength. This study sum-marises a part of the activities conducted by the Working Group 2 of COST Action FP1402, by presenting an in-depth review of the research works that have analysed the seismic behaviour of CLT structural systems. Thefirstpart of the paper discusses the outcomes of the testing programmes carried out in the lastfifteen years anddescribes the modelling strategies recommended in the literature. The second part of the paper introduces theq-behaviour factor of CLT structures and provides capacity-based principles for their seismic design.
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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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Assessment of Bending Properties of Sawn and Glulam Blackwood in Portugal

https://research.thinkwood.com/en/permalink/catalogue2463
Year of Publication
2020
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)

Behavior of Strengthened Timber Concrete Composite Under Axial Loads

https://research.thinkwood.com/en/permalink/catalogue2778
Year of Publication
2021
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Author
El-Salakawy, Tarek
Gamal, Amr
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
Timber-Concrete Composite
Topic
Mechanical Properties
Keywords
Axial Loading
Strengthening
Wire Mesh
Epoxy
Modulus of Elasticity
Failure Mode
Ductility
Post Failure Behavior
Language
English
Research Status
Complete
Series
Case Studies in Construction Materials
Summary
The research study focuses on different strengthening techniques for timber concrete composites (TCC) using different types of wire and wire mesh integrated with a layer of epoxy on a timber core embedded in concrete using experimental and analytical procedure. The impact of TCC on axial compression performance, modulus of elasticity, failure mode and post failure behavior and ductility were compared to reference concrete specimens. Different types of wire and wire mesh used in strengthening of the timber core, timber core size and reinforcement in the concrete cylinder were all parameters considered in this study. Timing of application of the epoxy on the wire strengthened timber core was very important. For structural applications, where the weight reduction and ductility as well as post failure endurance are essential, the development of this composite is recommended. The ratio of the ductility index to the weight is discussed. The light weight of the timber composite, and the increased ductility were noted in this study. An equation to estimate the axial compression capacity of the strengthened timber concrete composite was developed in this study. This study will pave the way for further applications for timber concrete composite aiming at reducing dead weight of concrete and the reducing the amount of concrete and steel in construction.
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Bending Properties of Cross Laminated Timber with Layer Arrangement Using Different Species

https://research.thinkwood.com/en/permalink/catalogue1599
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Park, Sun-Hyang
Kim, Keon-Ho
Lee, Sang-Joon
Pang, Sung-Jun
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Delamination Test
Bending Test
Japanese Larch
Korean Red Pine
Shear Strength
MOE
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1931-1938
Summary
To evaluate the mechanical performance of the cross laminated timber (CLT) as the structural board materials using domestic species, the delamination test and the transverse bending test were conducted. The CLT used in the tests consisted of 3 layers of laminated timber made of Japanese larch and Korean red pine. The combinations for lamination were then divided on species of layer and grades of laminae. In the bending test, the loading directions were shown to be parallel and perpendicular to width direction of specimens, which is considered as the applicable direction in wooden building. The result of test showed that the bending strength of larix CLT was higher than that of pine CLT in combination of single species. In case of combination of mixed species, the bending properties CLT using larix major layer was higher than those of pine surface layer. It means that the surface layer has a more influence on bending properties of CLT, than the core layer does.
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Connection and Performance of Two-Way CLT Plates

https://research.thinkwood.com/en/permalink/catalogue1482
Year of Publication
2018
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Roofs
Author
Zhang, Chao
Lee, George
Lam, Frank
Organization
University of British Columbia
Year of Publication
2018
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Floors
Roofs
Topic
Mechanical Properties
Connections
Keywords
Two-Way
Bending Test
Modulus of Elasticity
Self-Tapping Screws
Glued-In-Rod
Steel Connectors
Steel Plates
Language
English
Research Status
Complete
Summary
The two-way action of Cross Laminated Timber (CLT) is often ignored in the design of CLT due to its complexity. But in some cases, for example, large span timber floor/roof, the benefit of taking the two-way action into account may be considerable since it is often deflection controlled in the design. Furthermore CLT panels are typically limited to widths of less than 3 m. therefore, for practical applications, engaging CLT panels in two-way action as a plate in bending would require connecting two panels in the width/minor direction to take out-of-plane loading. To address this technically difficult situation, an innovative connection was developed to join the CLT panels in the minor direction to form a large continuous two-way plate. The two-way action of CLT was also quantified. Static bending test was conducted on CLT panels in the major and minor directions to measure the Modulus of Elasticity (MOE). This provided a benchmark for the following connection test, and data for the future development of computer modeling. The average apparent MOE was 9.09 GPa in the major direction and 2.37 GPa in the minor direction. Several connection techniques were considered and tested, including self-tapping wood screws, glued in steel rods, and steel connectors. One connecting system was found to be effective. For the panel configuration considered, the system was consisted of steel plates, self-tapping wood screws, and 45° screw washers. Two steel plates were placed on the tension side with sixteen screws, and one steel plates was placed on the compression side with four screws. When the screws were driven into the wood, the screws were tightly locked with the washers and steel plates, and at the same time, the wood members were pulled together by the screws. This eliminated any original gap within the connection. The connector was installed to join two CLT members in the minor direction. They were tested under bending with the same setup as above. The connected panels had an average apparent MOE of 2.37 GPa, and an average shear-free MOE of 2.44 GPa, both of which were higher than the counterpart in the full panels. The moment capacity of the connected panels was also high. The minimum moment capacity was 3.2 times the design value. Two large CLT panels were tested under concentrated loading with four corners simply supported. The deflection of nine locations within the panels was measured. This data will be used to validate the computer modeling for CLT two-way action.
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Cross Laminated Timber (CLT) Beams Loaded in Plane: Testing Stiffness and Shear Strength

https://research.thinkwood.com/en/permalink/catalogue2136
Year of Publication
2019
Topic
Mechanical Properties
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Beams

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
Country of Publication
Romania
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
General Information
Keywords
Physical Properties
MOE
Bending Strength
Building Applications
Language
English
Romanian
Research Status
Complete
Series
Pro Ligno
ISSN
2069-7430
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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Development of Cross-Laminated Timber (CLT) Products from Stress Graded Canadian Hem-Fir

https://research.thinkwood.com/en/permalink/catalogue2595
Year of Publication
2020
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Author
Wei, Peixing
Wang, Brad
Li, Zhong
Ju, Ronghua
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Keywords
Hem-Fir
Modulus of Elasticity
Modulus of Rupture
Stress-Graded Lumber
Language
English
Research Status
Complete
Series
Wood Research
Summary
To explore the feasibility of hem-fir for CLT products, this work addressed the exploratory and pilot plant studies of hem-fir cross-laminated timber (CLT) products through mechanical tests. The hem-fir lumber was procured and then stress-graded based on dynamic modulus of elasticity (MOE). The resulted 5-ply prototype CLT products were then tested non-destructively and 3-ply pilot plant hem-fir CLT was tested destructively. The results showed that bending performance of hem-fir CLT panel can be predicted. Considering cost-competitiveness and end applications of hem-fir CLT products, the panel structure can be optimized based on the stress-graded data of hem-fir lumber.
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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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49 records – page 1 of 5.