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14 records – page 1 of 2.

Analytical Modeling of Lateral Strength and Stiffness of Inclined Self-Tapping Screw Connection

https://research.thinkwood.com/en/permalink/catalogue2651
Topic
Mechanical Properties
Connections
Author
Zhao, Ruihan
Organization
University of Alberta
Topic
Mechanical Properties
Connections
Keywords
Self-Tapping Screws
Lateral Strength
Lateral Stiffness
Withdrawal
Yield
Embedment
Research Status
In Progress
Summary
The objective of this research is to develop models for predicting lateral strength and stiffness of connections containing inclined self-tapping screws, by considering the contribution of the withdrawal and yield properties of the screws and embedment properties of the connecting members.
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Bond strength of GiR in cross-laminated timber: A preliminary study

https://research.thinkwood.com/en/permalink/catalogue2934
Year of Publication
2021
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Sofi, M.
Lumantarna, E.
Hoult, Ryan
Mooney, Michael
Mason, Nicholas
Lu, Jinghan
Organization
The University of Melbourne
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Glued-in Rod
Pull-Out Strength
Embedment Length
Moment Connections
Research Status
Complete
Series
Construction and Building Materials
Summary
The popularity of cross-laminated timber (CLT) has increased significantly over recent years, with numerous low- to mid-rise buildings being constructed with CLT panels as the load-bearing structural system. Glued-in rods (GiR) have been used in the construction and retrofitting of timber structures and recently found its use in CLT elements. Embedded into the timber with structural grade adhesives, GiR enable stiff connections between timber and other structural members. Due to the complex force mechanisms occurring within these joints, there is yet to be consensus on a suitable method to predict their pull-out strength or failure mechanism. There is lack of experimental research on performance of GiR embedded into CLT. This paper examines previous research on glued-in rod connections as typically applied to solid timber and other engineered timber products. It aims to identify the factors contributing to the strength and failure modes of this connection, as well as the current models that are used for the analysis and design of glued-in rods. A series of 30 experiments were undertaken to investigate the load carrying capacity of single GiR bonded into CLT panels to identify the influence of (i) the bonded length of rod; and, (ii) the direction of the middle ply of the CLT panel on these results. The experimental results indicate that the pull-out strength is largely dictated by the embedment length.
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Design Equations for Dowel Embedment Strength and Withdrawal Resistance for Threaded Fasteners in CLT

https://research.thinkwood.com/en/permalink/catalogue226
Year of Publication
2014
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Author
Kennedy, Shawn
Salenikovich, Alexander
Munoz, Williams
Mohammad, Mohammad
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Keywords
Embedment Strength
Threaded Fasteners
withdrawal resistance
Lag Screws
Self Drilling Screws
Canada
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The Canadian standard for engineering design in wood (CSA O86) adopted the European yield model for calculations of the lateral resistance of connections with dowel-type fasteners. This model takes into account the yielding resistance of the fastener, the assembly's geometry and the embedment strength of wood. The latter is considered a function of the relative density of wood and diameter of the fastener. The purpose of this study is to verify the significance of these variables as applied to the embedment strength for threaded dowel-type fasteners of diameters 6.4 mm and greater in Canadian glulam products. The importance of this research is justified by the growing interest in the use of large-diameter threaded fasteners in heavy timber and hybrid structures of high load-bearing capacity. Based on the results of 960 tests, a new design model for the embedment strength is proposed for potential implementation in CSA O86 standard and the impact of such a change is presented.
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Design Equations for Embedment Strength of Wood for Threaded Fasteners in the Canadian Timber Design Code

https://research.thinkwood.com/en/permalink/catalogue281
Year of Publication
2014
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Kennedy, Shawn
Salenikovich, Alexander
Munoz, Williams
Mohammad, Mohammad
Sattler, Derek
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Keywords
Dowel Type Fastener
Lateral Resistance
Yielding Resistance
Embedment Strength
Canada
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The Canadian standard for engineering design in wood (CSA O86) adopted the European yield model for calculations of the lateral resistance of connections with dowel-type fasteners. This model takes into account the yielding resistance of the fastener, the assembly's geometry and the embedment strength of wood. The latter is considered a function of the relative density of wood and diameter of the fastener. The purpose of this study is to verify the significance of these variables as applied to the embedment strength for threaded dowel-type fasteners of diameters 6.4 mm and greater in Canadian glulam products. The importance of this research is justified by the growing interest in the use of large-diameter threaded fasteners in heavy timber and hybrid structures of high load-bearing capacity. Based on the results of 960 tests, a new design model for the embedment strength is proposed for potential implementation in CSA O86 standard and the impact of such a change is presented.
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The Design of Cross-Laminated Timber Slabs with Cut-Back Glulam Rib Downstands - From Research to Live Project

https://research.thinkwood.com/en/permalink/catalogue1736
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Author
Papastavrou, Panayiotis
Smith, Simon
Wallwork, Tristan
McRobie, Allan
Niem, Nicholas
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Finite Element Modelling
Full-Scale
Embedment Depth
Reinforcement
Screws
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4809-4818
Summary
A research project was undertaken to investigate the behaviour of composite CLT slabs with glulam downstands cut back from the supports. A desk study and Finite Element Modelling (FEM) were used and evaluated on their ability to model and design such a structure, focusing on the cut back location and utilising reinforcement screws. The project included full-scale laboratory testing of a composite slab to failure with innovative data collection techniques such as Particle Image Velocimetry. A similar structural element was also used in a real construction project and the investigation gave insight towards its design. It was concluded that the embedment depth of reinforcement screws in the glulam downstand is key to the performance of the composite slab with full depth penetration advisable. FEM can give useful results for stress concentrations in the timber and a simplified design method was proposed.
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Dowelled Timber Connections with Internal Members of Densified Veneer Wood and Fibre-Reinforced Polymer Dowels

https://research.thinkwood.com/en/permalink/catalogue1498
Year of Publication
2016
Topic
Mechanical Properties
Connections
Material
LVL (Laminated Veneer Lumber)
Author
Palma, Pedro
Kobel, Peter
Minor, Alexander
Frangi, Andrea
Year of Publication
2016
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Connections
Keywords
Timber-to-Timber
Densified Veneer Wood
Fibre-Reinforced Polymer
Dowel Type Fastener
Embedment Tests
Bending Test
Shear Test
Full Scale
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 236-243
Summary
The mechanical behaviour of timber-to-timber connections with internal panels of densified veneer wood (DVW) and fibre-reinforced polymer (FRP) dowels was experimentally assessed and a design method, based on EN 1995-1-1, was developed. Embedment tests on DVW plates and bending/shear tests on FRP dowels were performed to characterise these components, followed by full-scale tests of connections assembled with these materials. The results show that these connections exhibit a mechanical behaviour compatible with structural applications, regarding both load-carrying capacity and ductility. The proposed design model is based on EN 1995-1-1’s expressions for connections with dowel-type fasteners and gives good predictions of the experimental load-carrying capacities.
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Dynamic Behaviour of Dowel-Type Connections Under In-Service Vibration

https://research.thinkwood.com/en/permalink/catalogue884
Year of Publication
2013
Topic
Connections
Serviceability
Acoustics and Vibration
Material
Solid-sawn Heavy Timber
Application
Frames
Beams
Author
Reynolds, Thomas
Organization
University of Bath
Year of Publication
2013
Format
Thesis
Material
Solid-sawn Heavy Timber
Application
Frames
Beams
Topic
Connections
Serviceability
Acoustics and Vibration
Keywords
dowel-type connections
Embedment
Nonlinear Behaviour
Time Dependent Behaviour
Energy Dissipation
Portal Frames
Research Status
Complete
Summary
This study investigated the vibration serviceability of timber structures with dowel-type connections. It addressed the use of such connections in cutting-edge timber structures such as multi-storey buildings and long-span bridges, in which the light weight and flexibility of the structure make it possible that vibration induced by dynamic forces such as wind or footfall may cause discomfort to occupants or users of the structure, or otherwise impair its intended use. The nature of the oscillating force imposed on connections by this form of vibration was defined based on literature review and the use of established mathematical models. This allowed the appropriate cyclic load to be applied in experimental work on the most basic component of a dowel-type connection: a steel dowel embedding into a block of timber. A model for the stiffness of the timber in embedment under this cyclic load was developed based on an elastic stress function, which could then be used as the basis of a model for a complete connector. Nonlinear and time-dependent behaviour was also observed in embedment, and a simple rheological model incorporating elastic, viscoelastic and plastic elements was fitted to the measured response to cyclic load. Observations of the embedment response of the timber were then used to explain features of the behaviour of complete single- and multiple-dowel connections under cyclic load representative of in-service vibration. Complete portal frames and cantilever beams were tested under cyclic load, and a design method was derived for predicting the stiffness of such structures, using analytical equations based on the model for embedment behaviour. In each cyclic load test the energy dissipation in the specimen, which contributes to the damping in a complete structure, was measured. The analytical model was used to predict frictional energy dissipation in embedment, which was shown to make a significant contribution to damping in single-dowel connections. Based on the experimental results and analysis, several defining aspects of the dynamic response of the complete structures, such as a reduction of natural frequency with increased amplitude of applied load, were related to the observed and modelled embedment behaviour of the connections.
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Embedment Strength of Cross-Laminated Timber for Smooth Dowel-type Fasteners

https://research.thinkwood.com/en/permalink/catalogue2118
Year of Publication
2019
Topic
Connections
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Dong, Weiqun
Li, Qiao
Zhang, Hao
Wang, Zhiqiang
Zhou, Jianhui
Gong, Meng
Year of Publication
2019
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Design and Systems
Keywords
Fasteners
Embedment Strength
Failure Modes
Embedment Tests
Dowel-Type Connections
Conference
International Conference on Advances in Civil Engineering and Materials
Research Status
Complete
Series
MATEC Web of Conferences
Online Access
Free
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Experimental Investigation of Connection for the FFTT, A Timber-Steel Hybrid System

https://research.thinkwood.com/en/permalink/catalogue269
Year of Publication
2013
Topic
Connections
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Bhat, Pooja
Organization
University of British Columbia
Year of Publication
2013
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Connections
Design and Systems
Mechanical Properties
Keywords
FFTT
Quasi-Static
Monotonic Testing
Reverse Cyclic Testing
Embedment Depth
Embedment Length
Strong-column Weak-beam Failure
Cross-Section Reduction
Research Status
Complete
Summary
This thesis fills the existing knowledge gap between detailed design and global behaviour of hybrid systems through an experimental study on an innovative timber-steel hybrid system called “FFTT”. The FFTT system relies on wall panels of mass timber such as CLT for gravity and lateral load resistance and embedded steel sections for ductility under the earthquake loads. An important step towards the practical application of the FFTT system is obtaining the proof that the connections facilitate the desired ductile failure mode. The experimental investigation was carried out at the facility of FPInnovations, Vancouver. The testing program consisted of quasi-static monotonic and reverse cyclic tests on the timber-steel hybrid system with different configurations. The two beam profiles, wide flange I-sections and hollow rectangular sections were tested. The interaction between the steel beams and CLT panels and the effect of the embedment depth, cross-section reduction and embedment length were closely examined. The study demonstrated that when using an appropriate steel section, the desired ‘Strong Column–Weak Beam’ failure mechanism was initiated and excessive wood crushing was avoided. While wide-flange I-sections were stiffer and stronger, the hollow sections displayed better post-yield behaviour with higher energy dissipation capacity through several cycles of deformation under cyclic loads. The out-of-plane buckling at the point of yielding was the major setback of the embedment of wide-flange I-sections. This research served as a precursor for providing design guidance for the FFTT system as one option for tall wood buildings in high seismic regions.
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Influence of different types of reinforcements on the embedment behavior of steel dowels in wood

https://research.thinkwood.com/en/permalink/catalogue3082
Year of Publication
2016
Topic
Mechanical Properties
Connections
Author
Lederer, Wolfgang
Bader, Thomas K.
Unger, Gerhard
Eberhardsteiner, Josef
Organization
Vienna University of Technology
Publisher
Springer
Year of Publication
2016
Format
Journal Article
Topic
Mechanical Properties
Connections
Keywords
Dowel-Type Connection
Embedment Strength
European Yield Model
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
In this study, dowel displacement-embedment stress relationships for different types, numbers and positions of reinforcements were experimentally investigated using a half-hole embedment test setup. Tests were performed parallel to the grain and in compression. Screws with a full or partial thread at different positions below the dowel and oriented strand board, plywood and nail plates on the loaded surfaces of the specimens, served as reinforcements. Test results underline their potential for an increased ductility of dowel-type connections. Comparison of reinforced and unreinforced specimens suggests premature failure of the unreinforced wood and consequently, an underestimation of the embedment strength as it is subsequently used in the design of dowel connections using the European yield model. This was supported by the investigation of cracks on the surface of the specimens visualized by means of a full-field deformation measurement system. It could be demonstrated that the strength in the embedment test even further increases if the reinforcement elements actively contribute to the load transfer. This property however cannot be considered as embedment strength, but represents the strength of a connection system. Test data is compared to the design equation in Eurocode 5.
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14 records – page 1 of 2.