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17 records – page 1 of 2.

Analysis of Glue Line and Correlations Between Anatomical Characteristics of Eucalyptus grandis × Eucalyptus urophylla Glued-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2435
Year of Publication
2019
Topic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems

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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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
Country of Publication
Switzerland
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
Language
English
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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The Charring Rate of Glulam Beams of Brazilian Wood Species

https://research.thinkwood.com/en/permalink/catalogue1771
Year of Publication
2016
Topic
Fire
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Martins, Gisele
Munaiar Neto, Jorge
Calil Junior, Carlito
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Fire
Keywords
Charring Rate
Brazil
Density
Fire Test
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 5302-5309
Summary
The combustibility of timber is one of the factors that restrict the use of structural elements of wood in buildings in Brazil. This paper describes an experimental investigation of the charring rate of wood species. The charring rate is one of the key parameters for the design of load bearing timber structures. The purpose of this study is...
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Comparison of Bonding Performance Between Plywood and Laminated Veneer Lumber Induced by High Voltage Electrostatic Field

https://research.thinkwood.com/en/permalink/catalogue2487
Year of Publication
2019
Topic
Mechanical Properties
Design and Systems
Material
LVL (Laminated Veneer Lumber)
Other Materials
Application
Wood Building Systems

Curved Cross Laminated Timber Elements

https://research.thinkwood.com/en/permalink/catalogue1545
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Stecher, Georg
Maderebner, Roland
Zingerle, Philipp
Flach, Michael
Kraler, Anton
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Rolling Shear
Tensile Stress
Strength
Rigidity
Density
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1131-1138
Summary
In timber construction, curved timber components have been used repeatedly. Yet the use of curved CLT elements is a relatively recent phenomenon. To obtain a European Technical Approval (ETA) for so-called radius timber (single curved CLT elements), Holzbau Unterrainer GmbH commissioned the accredited testing institution TVFA – Innsbruck to carry out the tests required for this purpose. To this end, overall 158 tests were performed in building component dimensions from December 2013 to May 2014, and several laboratory tests were carried out to monitor adhesive joint quality. Due to the single curved shape of radius timber elements, it is key to particularly focus on possible implications on load bearing capacity due to pre-stress of the slats and to the tensile stress perpendicular to grain resulting from deflection forces. To comply with the criteria laid down in the semi-probabilistic safety concept used in Eurocode 5, the impact caused by these pre-curvatures on strength, rigidity and gross density must be known.
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Cyclic Performance of Connections used in Hybrid Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1367
Year of Publication
2017
Topic
Connections
Design and Systems
Material
CLT (Cross-Laminated Timber)
Author
Mahdavifar, Vahid
Organization
Oregon State University
Year of Publication
2017
Country of Publication
United States
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Design and Systems
Keywords
North American Market
Density
Low-Grade
High-Grade
Fasteners
Economical
Language
English
Research Status
Complete
Summary
One of the recent additions to the panoply of engineered wood products is cross-laminated timber (CLT). CLT is a prefabricated, large-scale, solid wood panel that consists of multiple layers of lumbers stacked together, with each layer arranged perpendicular to the next layer, glued with structural grade adhesives, and pressed. The use of massive CLT panels in wood construction provides several advantages over the traditional wood frame systems, making it particularly attractive for tall wood building construction. These main advantages are satisfactory distribution of defects, adequate seismic performance, ability to carry large loads, improved strength and stiffness, adequate acceptable fire performance, acceptable acoustic performance, and improved pre-fabrication.It is expected that as the CLT market will continue to mature, more diversified grades and special CLT products will be introduced into the markets. One special CLT product developed in at Oregon State University has been designated as hybrid CLT. Hybrid CLT refers to CLT panels manufactured with layers of high- and low-grade and low-density species, which aims at improving the economic efficiency and sustainability of the CLT industry with focus on the North America market.One of the potential issues with hybrid CLT panel application is related to the unknown performance of the connection systems which are highly dependent on the density of the wood in which the fasteners embed. Most of the existing models that have been developed for estimation of the fasteners capacities in withdrawal and lateral loading scenarios are developed based on the assumption of uniform density profile across the layers to which fasteners penetrate. In a hybrid CLT panel, there is a possibility of a variation in density profile along the panel thickness so that the fasteners can be driven into wood of different densities and driven in directions parallel and perpendicular to grain. Because of the potential variation in density profile in the hybrid CLT, the connection system performance cannot be predicted using design models used for uniform density profile applications similar to the models in National Design Specification (NDS) [1]. Therefore, there is a need for evaluation of connections performance in hybrid layup.The main objective of this work is to characterize the performance of connection systems for hybrid CLT. This is achieved through testing and modeling of single fastener connections and then testing and modeling of the typical connection systems. So, the specific objectives are: (1) evaluate the single fasteners performance to account for density variation and compare the results to a proposed modified model, (2) perform an experimental program to test different connection systems with different hybrid CLT panel layups, (3) develop a numerical algorithm based on the use of meta-heuristics tools to fit the optimal parameters for constitutive models to match the experimental data for the connection systems, (4) obtain the optimal parameters for constitutive models of the connection systems tested.
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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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Estimation of Radio Frequency Electric Field Strength for Dielectric Heating of Phenol-Resorcinol-Formaldehyde Resin Used for Manufacturing Glulam

https://research.thinkwood.com/en/permalink/catalogue1505
Year of Publication
2014
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Yang, Sang-Yun
Han, Yeonjung
Park, Yonggun
Eom, Chang-Deuk
Kim, Se-Jong
Kim, Kwang-Mo
Park, Moon-Jae
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2014
Country of Publication
Korea
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Keywords
Adhesives
Phenol-Resorcinol Formaldehyde
Larch
High Frequency
Specific Heat
Density
Dielectric
Language
Korean
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
For enhancing productivity of glulam, high frequency (HF) curing technique was researched in this study. Heat energy is generated by electromagnetic energy dissipation when HF wave is applied to a dielectric material. Because both lamina and adhesives have dielectric property, internal heat generation would be occurred when HF wave is applied to glulam. Most room temperature setting adhesives such as phenol-resorcinol-formaldehyde (PRF) resin, which is popularly used for manufacturing glulam, can be cured more quickly as temperature of adhesives increases. In this study, dielectric properties of larch wood and PRF adhesives were experimentally evaluated, and the mechanism of HF heating, which induced the fast curing of glue layer in glulam, was theoretically analyzed. Result of our experiments showed relative loss factor of PRF resin, which leads temperature increase, was higher than that of larch wood. Also, it showed density and specific heat of PRF, which are resistance factors of temperature increase, were higher than those of wood. It was expected that the heat generation in PRF resin by HF heating would occur greater than in larch wood, because the ratio of relative loss factor to density and specific heat of PRF resin was greater than that of larch wood. Through theoretical approach with the experimental results, the relative strengths of ISM band HF electric fields to achieve a target heating rate were estimated.
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Evaluation of Uniformity of Bamboo Bundle Veneer and Bamboo Bundle Laminated Veneer Lumber (BLVL)

https://research.thinkwood.com/en/permalink/catalogue2475
Year of Publication
2019
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Other Materials
Author
Zhou, Haiying
Wei, Xin
Smith, Lee
Wang, Ge
Chen, Fuming
Publisher
MDPI
Year of Publication
2019
Country of Publication
Switzerland
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Other Materials
Topic
Mechanical Properties
Keywords
Density
Light Transmittance
Stiffness
Language
English
Research Status
Complete
Series
Forests
Online Access
Free
Resource Link
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17 records – page 1 of 2.