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Development of Adhesive Free Engineered Wood Products - Towards Adhesive Free Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2029
Year of Publication
2018
Topic
Connections
Design and Systems
Environmental Impact
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Author
Guan, Zhongwei
Sotayo, Adeayo
Oudjene, Marc
el Houjeyri, Imane
Harte, Annette
Mehra, Sameer
Haller, Peer
Namari, Siavash
Makradi, Ahmed
Belouettar, Salim
Deneufbourg, Franscois
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Topic
Connections
Design and Systems
Environmental Impact
Mechanical Properties
Keywords
Adhesives
Manufacturing
Compressed Wood
Four Point Bending Test
Numerical Models
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
Over 5 million m 3 of engineered wood products (EWPs) are produced in the EU annually and the market is rising. However, EWPs have a high degree of petrochemical use in their manufacturing. In addition, throughout the life span of these EWP products from manufacture to disposal, they emit formaldehyde and other volatile organic compounds (VOCs), which makes recycling very difficult. In this paper, preliminary experimental work on Adhesive Free Engineered Wood Products (AFEWPs) is presented, which covers (1) manufacture of compressed wood (CW) dowels, (2) fabrication of adhesive free laminated beams and connections, (3) structural testing of AFEWPs. Also, the finite element models are being developed to assist designing of AFEWPs in terms of size of compressed wood dowel and dowel patterns in order to maximise their stiffness and load carrying capacities.
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Effects of the Thickness of Cross-Laminated Timber (CLT) Panels Made from Irish Sitka Spruce on Mechanical Performance in Bending and Shear

https://research.thinkwood.com/en/permalink/catalogue990
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Sikora, Karol
McPolin, Daniel
Harte, Annette
Publisher
ScienceDirect
Year of Publication
2016
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Sitka Spruce
Thickness
Bending Stiffness
Rolling Shear Strength
Research Status
Complete
Series
Construction and Building Materials
Summary
An investigation was carried out on CLT panels made from Sitka spruce in order to establish the effect of the thickness of CLT panels on the bending stiffness and strength and the rolling shear. Bending and shear tests on 3-layer and 5-layer panels were performed with loading in the out-of-plane and in-plane directions. ‘Global’ stiffness measurements were found to correlate well with theoretical values. Based on the results, there was a general tendency that both the bending strength and rolling shear decreased with panel thickness. Mean values for rolling shear ranged from 1.0 N/mm2 to 2.0 N/mm2.
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Evaluation of the Structural Behaviour of Beam-Beam Connection Systems Using Compressed Wood Dowels and Plates

https://research.thinkwood.com/en/permalink/catalogue2050
Year of Publication
2018
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Mehra, Sameer
O’Ceallaigh, Conan
Hamid-Lakzaeian, Fatemeh
Guan, Zhongwei
Sotayo, Adeayo
Harte, Annette
Organization
National University of Ireland Galway
University of Liverpool
Year of Publication
2018
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Keywords
Beam-to-Beam
Compressed Wood Dowels
Compressed Wood Plates
Four Point Bending Test
Load Carrying Capacity
Failure Modes
Moment Resistance
Rotational Stiffness
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
To support the transition to a bio-based society, it is preferable to substitute metallic fasteners and adhesives in timber construction with an eco-friendly alternative. Recent studies have identified compressed wood dowels and plates as a possible substitute for metallic fasteners in contemporary and mainstream applications. In this study, a spliced beam-beam connection system using compressed wood dowels and slotted-in compressed wood plates was examined under four-point bending. The study has considered specimens with compressed wood dowels of 10 mm diameter and compressed wood plates of 10 mm thickness. The load carrying capacity of connections using compressed wood dowels and plates were compared to connections utilising steel dowels and plates of equivalent capacity. Typical failure modes, moment resistance and rotational stiffness of both connection systems are evaluated on the basis of the experimental results. Tests have demonstrated similar failure modes when comparing steel-timber and compressed wood-timber connection systems. The mean failure load for the compressed wood-timber connection system is only 20.3% less than that achieved for the steel-timber connection system. The mean rotational stiffness of the compressed wood-timber connection system is 18.55% less than that achieved for the steel-timber connection system. These preliminary results demonstrate the potential for the use of compressed wood elements in the manufacture of timber connections.
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Experimental characterisation of the moment-rotation behaviour of beam-beam connections using compressed wood connectors

https://research.thinkwood.com/en/permalink/catalogue3131
Year of Publication
2021
Topic
Connections
Author
Mehra, Sameer
O'Ceallaigh, Conan
Sotayo, Adeayo
Guan, Zhongwei
Harte, Annette M.
Organization
National University of Ireland Galway
University of Liverpool
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Topic
Connections
Keywords
Compressed Wood Connectors
Dowel-Type Connections
Eurocode 5
Moment Rotation Behaviour
Beam-beam Connections
Research Status
Complete
Series
Engineering Structures
Summary
The widespread use of energy-intensive metallic connectors and synthetic adhesives in modern timber construction has negative implications for the end-of-life disposal or re-use of the structural timber components. Therefore, it is favourable to substitute metallic connectors and synthetic adhesives with bio-based alternatives such as wood-based connectors. Recent studies have shown that densified or compressed wood (CW) with superior mechanical properties could be suitable for the manufacture of wood-based connectors in the form of CW dowels and CW plates. This study experimentally examines the moment-rotation behaviour of semi-rigid type timber-CW beam-beam connections under pure bending. The study also assesses the suitability of current design rules to predict the moment capacity of timber-CW connections. The comparative study has shown that the moment capacity of the timber-CW connection can be conservatively predicted from the characteristic load-carrying capacity of the connections calculated using the EC 5 strength equations.
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Failure Modes and Reinforcement Techniques for Timber Beams – State of the Art

https://research.thinkwood.com/en/permalink/catalogue11
Year of Publication
2015
Topic
Serviceability
Material
Solid-sawn Heavy Timber
Application
Beams
Author
Harte, Annette
Franke, Bettina
Franke, Steffen
Publisher
ScienceDirect
Year of Publication
2015
Format
Journal Article
Material
Solid-sawn Heavy Timber
Application
Beams
Topic
Serviceability
Keywords
Damage
Deterioration
Failure
Fasteners
Large Span
Loading
Reinforcement
Retrofit
Research Status
Complete
Series
Construction and Building Materials
Summary
Highly loaded and large span timber beams are often used for halls, public buildings or bridges. Reinforcement of beams may be required to extend the life of the structure, due to deterioration or damage to the material/product or change of use. The paper summarises methods to repair or enhance the structural performance of timber beams. The main materials/products cross sections and geometries used for timber beam are presented. Furthermore, their general failure modes are described and typical retrofitting and reinforcement techniques are given. The techniques include wood to wood replacements, use of mechanical fasteners and additional strengthening materials/products.
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Influence of Connection Systems on Serviceability Response of CLT Timber Flooring

https://research.thinkwood.com/en/permalink/catalogue1690
Year of Publication
2016
Topic
Mechanical Properties
Acoustics and Vibration
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Uí Chúláin, Caitríona
Sikora, Karol
Harte, Annette
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Acoustics and Vibration
Serviceability
Keywords
Finite Element Analysis
Support Conditions
Two-Way
One-Way
Deflection
Displacement
Frequency
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4246-4253
Summary
In this paper finite element analysis of a five layer cross-laminated timber (CLT) rectangular floor is presented. The model was developed using 3D shell elements with linear elastic orthotropic material properties. Support conditions analysed included fully fixed, semi-rigid and simply supported, and both one and two-way span conditions were considered. For each case, the serviceability deflection was determined from a static small displacement analysis and the first three natural frequencies bending and torsional mode shapes, within a 0-80 Hz range, from mode frequency analysis. The analysis shows that the maximum displacement and frequency response are significantly impacted by the support stiffness and the number of edges supported. These results will contribute to determining the optimum fixing configuration with regard to serviceability limit design (SLD) for various CLT floor geometries.
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The Influence of Panel Lay-Up on the Characteristic Bending and Rolling Shear Strength of CLT

https://research.thinkwood.com/en/permalink/catalogue2179
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
O’Ceallaigh, Conan
Sikora, Karol
Harte, Annette
Organization
National University of Ireland Galway
University of Wollongong in Dubai
Publisher
MDPI
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Strength
Lay-up
Rolling Shear Strength
Bending Strength
Research Status
Complete
Series
Buildings
Summary
The objective of this study was to characterise the behaviour of cross laminated timber (CLT) panels and the influence of the panel lay-up on the failure strength. Three different panel configurations of thickness, 60 mm, 100 mm, and 120 mm, were loaded in the out-of-plane direction. The 60 mm and 120 mm panel configuration comprised three layers of equal thickness, and the intermediate 100 mm thick panel comprised five layers of equal thickness. The mean and characteristic bending and rolling shear strength of the panels were examined. The results show that the mean bending and rolling shear strength decrease with the panel thickness. The characteristic results have shown that there is an influence because of the number of boards within the panel. The characteristic bending strength values for the five-layer 100 mm thick panel were found to be higher than that of the three-layer 60 mm panel. The characteristic rolling shear values decreased in the five-layer panels, however, the increased number of layers subjected to the rolling shear results in a reduced variability in the rolling shear strength.
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Nonlinear Numerical Modelling of FRP Reinforced Glued Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue73
Year of Publication
2013
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Raftery, Gary
Harte, Annette
Publisher
ScienceDirect
Year of Publication
2013
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Fiber Reinforced Polymer
Finite Element Model
Flexural
Hybrid
Low-Grade
Model
Modulus of Rupture
Reinforcement
Stiffness
Strength
Spruce
Research Status
Complete
Series
Composites Part B: Engineering
Summary
Fibre-reinforced polymers (FRPs) are effective in the flexural stiffening and strengthening of structural members. Such systems can be optimised if accurate numerical models are developed. At present, limited information is available in the literature on numerical models that can predict with good accuracy the nonlinear behaviour of FRP reinforced low-grade glued laminated timber beams. This paper discusses the development of a finite element model, which incorporates nonlinear material modelling and nonlinear geometry to predict the load–deflection behaviour, stiffness, ultimate moment capacity and strain distribution of FRP plate reinforced glued laminated timber beams manufactured from mechanically stress graded spruce. Beams with and without sacrificial laminations are modelled and their performance is compared to unreinforced glued laminated timber beams. The model employed anisotropic plasticity theory for the timber in compression. The failure model used was the maximum stress criterion. Strong agreement was obtained between the predicted behaviour and the associated experimental findings. It was deduced from comparing the results from the numerical model with experimental findings that the FRP plate succeeds in increasing the performance of the adjacent timber significantly. The model is a useful tool for examination of the effect of reinforcement percentage and will be used for optimisation of the hybrid beam.
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Numerical Investigation of Reinforcement of Timber Elements in Compression Perpendicular to the Grain using Densified Wood Dowels

https://research.thinkwood.com/en/permalink/catalogue3112
Year of Publication
2021
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
O'Ceallaigh, Conan
Conway, Michael
Mehra, Sameer
Harte, Annette M.
Organization
National University of Ireland Galway
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Densified Wood Dowels
Finite Element Model
Cohesive Zone Modeling
Stresses Perpendicular to the Grain
Research Status
Complete
Series
Construction and Building Materials
Summary
In recent years, the construction industry has seen a greater focus on the use of sustainable construction materials to reduce the environmental impact of buildings. Timber is one such material that has seen a revival in its use due to its environmental credentials coupled with advances in the manufacture of engineered wood products and connection technologies. While timber and engineered wood products have a high strength-to-weight ratio suitable for large scale construction, timber is an orthotropic material and demonstrates poorer strength when loaded perpendicular to the grain. As a result, special consideration must be given to the design of areas of support where stress perpendicular to the grain develops in timber structures. This paper describes a study which examines the use of densified wood dowels as a sustainable reinforcement against perpendicular to the grain stresses using experimental and numerical approaches. Glued laminated timber samples were reinforced with 2, 4 and 6 densified wood dowels. The experimental results show significant improvements in load-bearing capacity can be achieved. A full 3-dimensional solid finite element model has been implemented in ABAQUS/Explicit software. The numerical model utilises cohesive zone modelling (CZM) and Hill plastic yield criterion to predict the failure behaviour of specimens utilising densified wood dowel reinforcement. The examined numerical modelling approach has been shown to give good predictions of the performance of the dowel-timber interaction and load-bearing capacity of the composite system. The numerical model has been also used in a parametric study to examine the influence of dowel diameter and dowel length on the failure behaviour. A maximum dowel length-to-diameter ratio is recommended based on the numerical results
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Review of State of the Art of Dowel Laminated Timber Members and Densified Wood Materials as Sustainable Engineered Wood Products for Construction and Building Applications

https://research.thinkwood.com/en/permalink/catalogue2385
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
DLT (Dowel Laminated Timber)
Application
Wood Building Systems

13 records – page 1 of 2.