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7 records – page 1 of 1.

Ambient Vibration Testing and Modal Analysis of Multi-Storey Cross Laminated Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue237
Year of Publication
2014
Topic
Acoustics and Vibration
Wind
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Reynolds, Thomas
Bolmsvik, Åsa
Vessby, Johan
Chang, Wen-Shao
Harris, Richard
Bawcombe, Jonathan
Bregulla, Julie
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Acoustics and Vibration
Wind
Serviceability
Keywords
Modal Properties
Multi-Storey
Damping
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The ambient movement of three modern multi-storey timber buildings has been measured and used to determine modal properties. This information, obtained by a simple, unobtrusive series of tests, can give insights into the structural performance of these forms of building, as well as providing information for the design of future, taller timber buildings for dynamic loads. For two of the buildings, the natural frequency has been related to the lateral stiffness of the structure, and compared with that given by a simple calculation. In future tall timber buildings, a new design criterion is expected to become important: deflection and vibration serviceability under wind load. For multi-storey timber buildings there is currently no empirical basis to estimate damping for calculation of wind-induced vibration, and there is little information for stiffness under wind load. This study therefore presents a method to address those gaps in knowledge.
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Ambient Vibration Tests of a Cross-Laminated Timber Building

https://research.thinkwood.com/en/permalink/catalogue313
Year of Publication
2015
Topic
Wind
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Shear Walls
Author
Reynolds, Thomas
Harris, Richard
Chang, Wen-Shao
Bregulla, Julie
Bawcombe, Jonathan
Publisher
ICE Publishing
Year of Publication
2015
Country of Publication
United Kingdom
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Shear Walls
Topic
Wind
Keywords
Damping
Dynamic Movement
In Situ
Multi-Storey
Stiffness
Modal Properties
Ambient Vibration Method
Language
English
Research Status
Complete
Series
Proceedings of the Institution of Civil Engineers - Construction Materials
ISSN
1747-6518
Summary
Cross-laminated timber has, in the last 6 years, been used for the first time to form shear walls and cores in multi-storey buildings of seven storeys or more. Such buildings can have low mass in comparison to conventional structural forms. This low mass means that, as cross-laminated timber is used for taller buildings still, their dynamic movement under wind load is likely to be a key design parameter. An understanding of dynamic lateral stiffness and damping, which has so far been insufficiently researched, will be vital to the effective design for wind-induced vibration. In this study, an ambient vibration method is used to identify the dynamic properties of a seven-storey cross-laminated timber building in situ. The random decrement method is used, along with the Ibrahim time domain method, to extract the modal properties of the structure from the acceleration measured under ambient conditions. The results show that this output-only modal analysis method can be used to extract modal information from such a building, and that information is compared with a simple structural model. Measurements on two occasions during construction show the effect of non-structural elements on the modal properties of the structure.
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Fire Performance of Metal-Free Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2186
Year of Publication
2015
Topic
Fire
Connections
Material
LVL (Laminated Veneer Lumber)
CLT (Cross-Laminated Timber)
Other Materials
Application
Wood Building Systems
Beams
Columns
Trusses
Author
Brandon, Daniel
Maluk, Cristian
Ansell, Martin
Harris, Richard
Walker, Pete
Bisby, Luke
Bregulla, Julie
Publisher
ICE Publishing
Year of Publication
2015
Country of Publication
United Kingdom
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
CLT (Cross-Laminated Timber)
Other Materials
Application
Wood Building Systems
Beams
Columns
Trusses
Topic
Fire
Connections
Keywords
Fire Performance
Steel Connections
Thermal Conductivity
Thermal Behaviour
Mechanical Behavior
Metal-Free Connections
Language
English
Research Status
Complete
Series
Proceedings of the Institution of Civil Engineers - Construction Materials
Notes
DOI link: http://dx.doi.org/10.1680/coma.14.00055
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Fire Performance of Metal-Free Timber Connections

https://research.thinkwood.com/en/permalink/catalogue82
Year of Publication
2015
Topic
Connections
Fire
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
Brandon, Daniel
Maluk, Cristian
Ansell, Martin
Harris, Richard
Walker, Pete
Bisby, Luke
Bregulla, Julie
Publisher
ICE Publishing
Year of Publication
2015
Country of Publication
United Kingdom
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Connections
Fire
Keywords
Glass Fiber Reinforced Polymer
Thermal Behaviour
Mechanical Behaviour
Language
English
Research Status
Complete
Series
Proceedings of the Institution of Civil Engineers - Construction Materials
ISSN
1747-6518
Summary
The fire performance of heavy timber frame structures is often limited by the poor fire performance of its connections. Conventional timber connections, dowelled or toothed plate connections typically use steel as a connector material. In a fire, the steel parts rapidly conduct heat into the timber, leading to reduced fire performance. Replacing metallic connectors with alternative non-metallic, low thermal conductivity connector materials can, therefore, lead to improved connection performance in fire. This paper presents an experimental study into the fire performance of metal-free timber connections comprising a hot-pressed plywood flitch plate and glass-fibre-reinforced polymer dowels. The thermal behaviour of the connections at elevated temperatures is studied using a standard cone calorimeter apparatus and a novel heat transfer rate inducing system. The latter is a fire testing system developed at the University of Edinburgh. The mechanical behaviour of the connection during severe heating was also studied using an environmental chamber at temperatures up to 610°C. The results demonstrate that heat transfer in the non-metallic connections is governed by the thermal properties of the timber, resulting in significant enhancements in connection fire performance.
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Lateral-Load Resistance of Cross-Laminated Timber Shear Walls

https://research.thinkwood.com/en/permalink/catalogue1238
Year of Publication
2017
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Reynolds, Thomas
Foster, Robert
Bregulla, Julie
Chang, Wen-Shao
Harris, Richard
Ramage, Michael
Publisher
American Society of Civil Engineers
Year of Publication
2017
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Mechanical Properties
Keywords
Vertical Load
Lateral Load
Pullout Tests
Steel Connectors
Offset-Yield Criterion
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
Cross-laminated timber shear wall systems are used as a lateral load resisting system in multistory timber buildings. Walls at each level typically bear directly on the floor panels below and are connected by nailed steel brackets. Design guidance for lateral load resistance of such systems is not well established and design approaches vary among practitioners. Two cross-laminated two-story timber shear wall systems are tested under vertical and lateral load, along with pull-out tests on individual steel connectors. Comprehensive kinematic behavior is obtained from a combination of discrete transducers and continuous field displacements along the base of the walls, obtained by digital image correlation, giving a measure of the length of wall in contact with the floor below. Existing design approaches are evaluated. A new offset-yield criterion based on acceptable permanent deformations is proposed. A lower bound plastic distribution of stresses, reflecting yielding of all connectors in tension and cross-grain crushing of the floor panel, is found to most accurately reflect the observed behavior.
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Nonlinear Pre-Yield Modal Properties of Timber Structures with Large-Diameter Steel Dowel Connections

https://research.thinkwood.com/en/permalink/catalogue132
Year of Publication
2014
Topic
Connections
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Frames
Author
Harris, Richard
Reynolds, Thomas
Chang, Wen-Shao
Publisher
ScienceDirect
Year of Publication
2014
Country of Publication
Netherlands
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Frames
Topic
Connections
Acoustics and Vibration
Keywords
Dowel-Type Connection
Modal Analysis
Cyclic Loading
Energy Dissipation
Language
English
Research Status
Complete
Series
Engineering Structures
Summary
In timber structures, the connections are generally flexible in comparison to the members they connect, and so contribute significantly to the dynamic properties of the structure. It is shown here that a widely-used form of connection, the dowel-type connection, exhibits nonlinear stiffness and energy dissipation, even at pre-yield loads, and that this nonlinearity affects the modal properties of structures with such connections. This study investigates that behaviour by modal analysis of a portal frame and a cantilever beam constructed from timber with steel dowel connections. The observed nonlinearity is explained qualitatively by considering the measured force-displacement response of individual connectors under cyclic load, which show a reduction in stiffness and an increase in energy dissipation with increasing amplitude of vibration. The structures were tested by modal analysis under slow sine sweep and pseudo-random excitation. Under pseudo-random excitation, a linear single degree-of-freedom curve fit was applied to estimate the equivalent linear modal properties for a given amplitude of applied force. Under slow sine sweep excitation, the frequency response function for the structures was observed to show features similar to a system with a cubic component of stiffness, and the modal properties of the structures were extracted using the equation of motion of such a system. The consequences for structural design and testing are that two key design parameters, natural frequency and damping, vary depending on the magnitude of vibration, and that parameters measured during in-situ testing of structures may be inaccurate for substantially different loads.
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Free
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Wind-Induced Vibration of Tall Wood Buildings

https://research.thinkwood.com/en/permalink/catalogue1105
Year of Publication
2011
Topic
Wind
Connections
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Reynolds, Thomas
Chang, Wen-Shao
Harris, Richard
Organization
TRADA
Year of Publication
2011
Country of Publication
United Kingdom
Format
Report
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Wind
Connections
Keywords
Across-Wind Vibration
Turbulence
Along-Wind Vibration
Vortex Shedding
Language
English
Research Status
Complete
Summary
Wind-induced vibration is an important design consideration in tall buildings in any structural material. The two main forms of wind-induced vibration - across-wind vibration due to vortex shedding and along-wind vibration due to turbulence - were taken into consideration when undertaking this study. Both types are addressed in Eurocode 1. This research summary discusses a study which, following a sensitivity study into the effect of stiffness and damping on wind-induced vibration, addresses a shortfall in current knowledge of stiffness in dowel-type connections. This type of connection is found in the glulam frame and CLT structures currently at the forefront of tall timber construction, and its behaviour was investigated by measuring and analysing stiffness and damping under oscillating loads representative of wind-induced vibration. This research summary covers a number of factors relating to wind-induced vibration which must be considered when constructing a tall timber building, such as how to assess connection stiffness under in-service vibration. The various conditions were then applied to a case study - the proposed Barentshaus building.
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7 records – page 1 of 1.