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7 records – page 1 of 1.

Connection Wood Brittle Failure in Cross-Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue1552
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Zarnani, Pouyan
Quenneville, Pierre
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Fasteners
Brittle Failure
Failure Modes
Stiffness-Based Design Approach
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1233-1240
Summary
The introduction of Cross-laminated Timber (CLT) as an engineered timber product has played a significant role in the considerable progress of timber construction in recent years. Extensive research has been conducted in Europe and more recently in Canada to evaluate the fastening capacity of different types of fasteners in CLT. While ductile capacities calculated using the yield limit equations are quite reliable for fastener resistance in connections, however, they do not take into account the possible brittle failure modes of the connection which could be the governing failure mode in multi-fastener joints. Therefore, a stiffness-based design approach which has already been developed by the authors and verified in LVL, glulam and lumber has been adapted to determine the block-tear out resistance of connections in CLT by considering the effect of perpendicular layers. The comparison between the test results on riveted connections conducted at the University of Auckland (UoA) and at the Karlsruhe Institute of Technology (KIT) and the predictions using the new model and the one developed for uniformly layered timber products show that the proposed model provides higher predictive accuracy and can be used as a design provision to control the brittle failure of wood in CLT connections.
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Ductility and Overstrength of Dowelled LVL and CLT Connections Under Cyclic Loading

https://research.thinkwood.com/en/permalink/catalogue1504
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Author
Ottenhaus, Lisa-Mareike
Li, Minghao
Smith, Tobias
Quenneville, Pierre
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Ductility
Overstrength
Cyclic Loading
Monotonic Loading
Dowels
Ductile Failure
Brittle Failure
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 325-333
Summary
This paper presents an experimental study on ductility and overstrength of dowelled connections. Connection ductility and overstrength derived from monotonic testing are often used in timber connection design in the context of seismic loading, based on the assumption that these properties are similar under monotonic and cyclic loading. This assumption could possibly lead to non-conservative connection design. Therefore, it is necessary to quantify ductility and overstrength for cyclic loading and contrast them with their monotonic performance. For this purpose, monotonic and quasi-static cyclic experimental tests were performed on dowelled LVL and CLT connections. The experimental results were also compared with strength predictions from state-of-the-art analytical models in literature that were verified for ductile and brittle failure under monotonic loading. This work also allowed investigation into a generally applicable overstrength factor for push-pull loaded dowelled connections.
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Group Tear-Out in Small-Dowel-Type Timber Connections: Brittle and Mixed Failure Modes of Multinail Joints

https://research.thinkwood.com/en/permalink/catalogue579
Year of Publication
2014
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Author
Zarnani, Pouyan
Quenneville, Pierre
Publisher
American Society of Civil Engineers
Year of Publication
2014
Country of Publication
United States
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
dowel-type connections
Load Carrying Capacity
Brittle Failure
Failure Modes
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
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 summation of the tensile and shear capacities of the failed wood block planes. It is postulated that these methods are not appropriate since the stiffness of the adjacent wood loading the tensile and shear planes differs, and this leads to uneven load distribution among the resisting planes. 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. For the wood strength, the stiffness of the adjacent loading volumes and strength of the failure planes subjected to nonuniform shear and tension stresses are considered. The effective wood thickness for the brittle failure mode is derived and related to the elastic deformation of the fastener. A mixed failure mode is also defined (a mixture of brittle and ductile) and depends on the governing ductile failure mode of the fastener. To help the designer, an algorithm is presented that allows the designer to calculate the resistances associated with predictions of the different possible brittle, ductile, and mixed failure modes. The proposed stiffness-based model has already been verified in brittle and mixed failure modes of timber rivet connections. In the research reported in this paper, an extended application is proposed for other small-dowel-type fasteners such as nails and screws. Results of nailed joint tests on laminated veneer lumber (LVL) and the test data available from the literature on glulam confirm the validity of this new method, and show that it can be used as a design provision for wood load-carrying capacity prediction of small-dowel-type timber connections.
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Mechanical Behavior of Bolted Glulam Beam-to-Column Connections with Slotted-In Steel Plates Under Pure Bending

https://research.thinkwood.com/en/permalink/catalogue1503
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Columns
Author
Wang, Mingqian
Song, Xiaobin
Gu, Xianglin
Wu, Yajie
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Columns
Topic
Connections
Mechanical Properties
Keywords
Full Scale
Bolted Connection
Beam-to-Beam
Beam-to-Column
Steel Plates
Finite Element Model
Failure Modes
Moment Resistance
Continuum Damage Mechanics
Brittle Failure
Ductile Failure
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 309-316
Summary
In this study, five full-scale bolted glulam beam-to-beam connections with slotted-in steel plates were conducted under a third-point loading, and a three-dimensional finite element method based model was also established to investigate the failure modes and moment resistance of such connections. A material model based on the Continuum Damage Mechanics (CDM) theory was developed to predict damage evolution of wood. Different damage variables were used to consider the ductile and brittle failure modes of wood, respectively. The test results indicated that splitting and shear plug failures were the main failure modes. The numerical analysis model prediction achieved fair agreements with the test results. The research could provide the guide for the design of bolted beam-to-column connections in heavy timber structures.
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New Design Approach for Controlling Brittle Failure Modes of Small-Dowel-Type Connections in Cross-Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue155
Year of Publication
2015
Topic
Connections
Design and Systems
Material
CLT (Cross-Laminated Timber)
Author
Zarnani, Pouyan
Quenneville, Pierre
Publisher
ScienceDirect
Year of Publication
2015
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Design and Systems
Keywords
Brittle Failure Mode
Fasteners
Stiffness
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
The introduction of Cross-laminated Timber (CLT) as an engineered timber product has played a significant role in considerable progress of timber construction in recent years. Extensive research has been conducted in Europe and more recently in Canada to evaluate the fastening capacity of different types of fasteners in CLT. While ductile capacities calculated using the yield limit equations are quite reliable for fastener resistance in connections, however, they do not take into account the possible brittle failure mode of the connection which could be the governing failure mode in multi-fastener joints. Therefore, a stiffness-based design approach which has already been developed by the authors and verified in LVL, glulam and lumber has been adapted to determine the block-tear out resistance of connections in CLT by considering the effect of perpendicular layers. The comparison between the test results on riveted connections conducted at the University of Auckland (UoA) and the Karlsruhe Institute of Technology (KIT) and the predictions using the new model and the one developed for uniformly layered timber products show that the proposed model provides higher predictive accuracy and can be used as a design provision to control the brittle failure of wood in CLT connections.
Online Access
Free
Resource Link
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Steel-Timber Versus Steel-Concrete Composite Floors: A Numerical Study

https://research.thinkwood.com/en/permalink/catalogue1765
Year of Publication
2016
Topic
Mechanical Properties
Material
Steel-Timber Composite
LVL (Laminated Veneer Lumber)
Application
Floors
Author
Keipour, Nicka
Valipour, Hamid
Bradford, Mark
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Steel-Timber Composite
LVL (Laminated Veneer Lumber)
Application
Floors
Topic
Mechanical Properties
Keywords
Screws
Finite Element Model
Load Carrying Capacity
Strength
Stiffness
Composite Action
Brittle Failure
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 5208-5216
Summary
Concrete is the most widely used construction material in the world. This material causes formation and release of CO2 and high energy consumption during manufacturing. One way to decrease concrete consumption negative consequences is to replace it with lower needed primary energy materials, like timber. The engineered wood products such as laminated veneer lumber (LVL)...
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Free
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Torque Loading Tests on the Rolling Shear Strength of Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1416
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Lam, Frank
Li, Yuan
Li, Minghao
Publisher
Springer Japan
Year of Publication
2016
Country of Publication
Japan
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Rolling Shear Strength
Polyurethane
Mountain Pine Beetle
Torque Loading Tests
Failure Modes
Monte Carlo
Finite Element Model
Brittle Failure
Language
English
Research Status
Complete
Series
Journal of Wood Science
ISSN
1611-4663
Summary
In this study , torque loading tests on small shear blocks were performed to evaluate the rolling shear strength of cross-laminated timber (CLT). The CLT plates in the tests were manufactured with Mountain Pine Beetle-afflicted lumber boards and glued with polyurethane adhesive; two types of layups (five-layer and three-layer) with a clamping pressure 0.4 MPa were studied. The small block specimens were sampled from full-size CLT plates and the cross layers were processed to have an annular cross section. These specimens were tested under torque loading until brittle shear failure occurred in the middle cross layers. Based on the test results, the brittle shear failure in the specimens was evaluated by detailed finite element models to confirm the observed failure mode was rolling shear. Furthermore, a Monte Carlo simulation procedure was performed to investigate the occurrence probability of different shear failure modes in the tests considering the randomness of the rolling shear strength and longitudinal shear strength properties in the wood material. The result also suggested the probability of rolling shear failure is very high, which gives more confident proof that the specimens failed dominantly in rolling shear. It was also found that the torque loading test method yielded different rolling shear strength values compared to the previous research from short-span beam bending tests; such a difference may mainly be due to the different stressed volumes of material under different testing methods, which can be further investigated using the size effect theory in the future.
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7 records – page 1 of 1.