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22 records – page 1 of 3.

Accelerated Curing of Large Scale Glued-in-Rods

https://research.thinkwood.com/en/permalink/catalogue2018
Year of Publication
2018
Topic
Mechanical Properties
Connections
Material
LVL (Laminated Veneer Lumber)

Adhesive Bonding of Structural Hardwood Elements

https://research.thinkwood.com/en/permalink/catalogue75
Year of Publication
2015
Topic
Mechanical Properties
Serviceability
Moisture
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Author
Hassani, Mohammad
Organization
ETH Zurich
Year of Publication
2015
Country of Publication
Switzerland
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Serviceability
Moisture
Keywords
Abaqus
Adhesives
Beech
Bonding
Delamination
Finite Element Model
Fracture
Long-term
Model
Hardwood
Language
English
Research Status
Complete
Summary
The current research investigated the delamination process of adhesively bonded hardwood (European beech) elements subject to changing climatic conditions. For the study of the long-term fracture mechanical behavior of gluedlaminated components under varying moisture content, the role of moisture development, time- and moisture-dependent responses are absolutely crucial. For this purpose, a 3D orthotropic hygro-elastic, plastic, visco-elastic, mechano-sorptive wood constitutive model with moisture-dependent material constants was presented in this work. Such a comprehensive material model is capable to capture the true historydependent stress states and deformations which are essential to achieve reliable design of timber structures. Besides the solid wood substrates, the adhesive material also influences the interface performance considerably. Hence, to gain further insight into the stresses and deformations generated in the bond-line, a general hygro-elastic, plastic, visco-elastic creep material model for adhesive was introduced as well. The associated numerical algorithms developed on the basis of additive decomposition of the total strain were formulated and implemented within the Abaqus Finite Element (FE) package. Functionality and performance of the proposed approach were evaluated by performing multiple verification simulations of wood components, under different combinations of mechanical loading and moisture variation. Moreover, the generality and efficiency of the presented approach was further demonstrated by conducting an application example of a hybrid wood element.
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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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Bondline Shear Strength and Wood Failure of European and Tropical Hardwood Glulams

https://research.thinkwood.com/en/permalink/catalogue1372
Year of Publication
2018
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Aicher, Simon
Ahmad, Zakiah
Hirsch, Maren
Publisher
Springer Berlin Heidelberg
Year of Publication
2018
Country of Publication
Germany
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Keywords
Keruing
Melangangai
Light Red Meranti
Sweet Chestnut
Oak
Beech
Ash
Teak
Hardwood
Shear Strength
Bondlines
Adhesives
Language
English
Research Status
Complete
Series
European Journal of Wood and Wood Products
ISSN
1436-736X
Summary
The study reports on block shear investigations with bondlines of face-glued laminations and matched solid wood specimens from hardwood glulam (GLT) beams produced industrially from eight technically and stand volume-wise important species. The European hardwoods comprised oak, beech, sweet chestnut and ash and the tropical species were teak, keruing, melangangai and light red meranti. The adhesives were phenol-resorcinol and melamine-urea. When combining all species in one sample, a rather strong linear relationship of bond and wood shear strength was observed. The ratio of bond vs. wood shear strength was for all species on the mean value level = 0.9, and likewise (with one exception) for the respective strengths’ 5%-quantiles. Consistent with literature, the test results showed no significant correlations between bond shear strength and density, wood shear strength and wood failure percentage of individual species, respectively. The investigations render the methodological basics of some international standards on bond quality verification as being inappropriate. New, empirically validated hardwood GLT bond requirements are proposed for discussion and implementation at the CEN and ISO levels. The strength ratio specifications reflect respective ANSI provisions, yet the reference quantity wood shear strength is now determined in an unbiased manner from matched GLT specimens. The wood failure verification proposal is based on the 10%-quantile and mean level for initial type testing and factory production control. The requirements further account for the pronounced difference observed in scatter of wood failure between European and tropical species.
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Development of a Spring Model for the Structural Analysis of a Double-Layered Timber Plate Structure with Through-Tenon Joints

https://research.thinkwood.com/en/permalink/catalogue2034
Year of Publication
2018
Topic
Design and Systems
Mechanical Properties
Connections
Material
LVL (Laminated Veneer Lumber)
Author
Chi Nguyen, Anh
Weinand, Yves
Year of Publication
2018
Country of Publication
South Korea
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Design and Systems
Mechanical Properties
Connections
Keywords
Beech
Joints
Finite Element Model
Double-Layered Timber Plate
Stiffness
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
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Free
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Effects of ACQ Preservative Treatment on the Mechanical Properties of Hardwood Glulam

https://research.thinkwood.com/en/permalink/catalogue253
Year of Publication
2012
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Yang, Te-Hsin
Lin, Chih-Hsien
Wang, Song-Yung
Lin, Far-Ching
Publisher
Springer-Verlag
Year of Publication
2012
Country of Publication
Germany
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Beech
Delamination
Hardwood
Maple
Modulus of Elasticity
non-destructive methods
Oak
Ultrasonic Wave
Tap Tone Method
Language
English
Research Status
Complete
Series
European Journal of Wood and Wood Products
ISSN
1436-736X
Summary
The purpose of this study is to examine the mechanical properties of ACQ-treated glulam made from three hardwood lumbers. Two nondestructive methods, ultrasonic wave and tap tone method, were also used in this study. The results showed that the dynamic MOE and static MOE of lumbers decreased with increased ACQ preservative retention. ANOVA showed no significant difference in the MOE values of glulam between untreated and ACQ-treated group. However, it was also found that glulam made from red oak lumbers had the highest bending strength retention ratio. The shear strength of the glulam also showed similar results. Finally, no delaminating was found in all glulams after the specimens under soaked and boiled delamination tests.
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Experimental Analysis of the Structural Behavior of Timber-Concrete Composite Slabs Made of Beech-Laminated Veneer Lumber

https://research.thinkwood.com/en/permalink/catalogue611
Year of Publication
2013
Topic
Connections
Mechanical Properties
Material
Timber-Concrete Composite
LVL (Laminated Veneer Lumber)
Application
Floors
Author
Boccadoro, Lorenzo
Frangi, Andrea
Publisher
American Society of Civil Engineers
Year of Publication
2013
Country of Publication
United States
Format
Journal Article
Material
Timber-Concrete Composite
LVL (Laminated Veneer Lumber)
Application
Floors
Topic
Connections
Mechanical Properties
Keywords
Beech
Spruce
Load Carrying Capacity
Structural Behavior
Failure Modes
Notch Connections
Language
English
Research Status
Complete
Series
Journal of Performance of Constructed Facilities
Summary
The wood engineering community has dedicated a significant amount of effort over the last decades to establish a reliable predictive model for the load-carrying capacity of timber connections under wood failure mechanisms. Test results from various sources (Foschi and Longworth 1975; Johnsson 2003; Quenneville and Mohammad 2000; Stahl et al. 2004; Zarnani and Quenneville 2012a) demonstrate that for multi-fastener connections, failure of wood can be the dominant mode. In existing wood strength prediction models for parallel to grain failure in timber connections using dowel-type fasteners, different methods consider the minimum, maximum or the summation of the tensile and shear capacities of the failed wood block planes. This results in disagreements between the experimental values and the predictions. It is postulated that these methods are not appropriate since the stiffness in the wood blocks adjacent to the tensile and shear planes differs and this leads to uneven load distribution amongst the resisting planes (Johnsson 2004; Zarnani and Quenneville 2012a). The present study focuses on the nailed connections. A closed-form analytical method to determine the load-carrying capacity of wood under parallel-to-grain loading in small dowel-type connections in timber products is thus proposed. The proposed stiffness-based model has already been verified in brittle and mixed failure modes of timber rivet connections (Zarnani and Quenneville 2013b).
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Field Testing on Innovative Timber Structures

https://research.thinkwood.com/en/permalink/catalogue671
Year of Publication
2014
Topic
Design and Systems
Material
LVL (Laminated Veneer Lumber)
Application
Floors
Frames
Author
Leyder, Claude
Wanninger, Flavio
Frangi, Andrea
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Application
Floors
Frames
Topic
Design and Systems
Keywords
Beech
Post-Tensioned
Office Buildings
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
In timber research, a main objective is the development and promotion of innovative and efficient timber structures. Therefore a pilot building, named ETH House of Natural Resources, has been designed, which uses two innovative structural systems, a post-tensioned timber frame and a composite beech LVL concrete floor. The building will be used as an office building for the Laboratory of Hydraulics, Hydrology and Glaciology from ETH Zürich and will serve as a showcase building of a sustainable and reliable timber construction for students and researchers, among others.
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Fire Tests on Timber-Concrete Composite Slabs Using Beech Laminated Veneer Lumber

https://research.thinkwood.com/en/permalink/catalogue1677
Year of Publication
2016
Topic
Fire
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Author
Klippel, Michael
Boccadoro, Lorenzo
Klingsch, Eike
Frangi, Andrea
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Topic
Fire
Keywords
Large Scale
Fire Resistance
Fire Test
Beech
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3942-3949
Summary
At the Institute of Structural Engineering (IBK) of ETH Zurich, the fire behaviour of timber-concrete composite slabs made with beech laminated veneer lumber (LVL) (BauBuche) was investigated. This composite slab is made of a thin plate (depth: 40 mm or 80 mm) using beech LVL and a concrete layer on top (depth: 160 mm or 120 mm). The beech plate acts both as formwork and as tensile reinforcement. This innovative slab system was implemented for the first time in the ETH House of Natural Resources at ETH Zurich. This paper summarizes the results of two largescale fire tests on loaded timber-concrete composite slabs exposed to standard ISO fire. Both fire tests show that the timber-concrete composite slab using beech LVL reaches sufficient fire resistance and integrity for 90 min and 60 min, respectively.
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Hybrid Beech and Spruce Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1547
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Aicher, Simon
Hirsch, Maren
Christian, Zachary
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Beech
Rolling Shear Modulus
Rolling Shear Strength
Shear Tests
Compression Shear
Bending Tests
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1147-1155
Summary
The presented work examines the rolling shear properties of beech wood for the novel application as cross-layers in hybrid cross-laminated timber. Rolling shear modulus and strength of beech were determined by three different approaches: i) two-plate shear tests on single beech board slabs, and ii) compression shear and iii) bending tests on hybrid CLT specimens based on the test methods defined in EN 16351. The CLT specimens were cut from two industrially manufactured hybrid three-layered CLT-plates with a beech cross-layer and spruce outer layers. The rolling shear modulus results obtained from the single board tests and the bending tests agreed well and were within the range of 350 - 370 N/mm². The characteristic rolling shear strength obtained from the bending tests was determined as 2.6 N/mm², where the failure was often governed by longitudinal shearing of the spruce laminations. Hybrid CLT-plates demonstrate a highly improved strength and deflection behaviour versus homogenous spruce CLT-plates and result in not only a mechanically superior product but also allow for a greatly simplified design approach.
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22 records – page 1 of 3.