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211 records – page 1 of 22.

Advanced Modelling of Cross Laminated Timber (CLT) Panels in Bending

https://research.thinkwood.com/en/permalink/catalogue1796
Year of Publication
2015
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Franzoni, Lorenzo
Lebée, Arthur
Lyon, Florent
Forêt, Gilles
Publisher
HAL archives-ouvertes.fr
Year of Publication
2015
Format
Presentation
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Mechanical Properties
Keywords
Bending
Model
Panels
Shear
Stiffness
Failure Behavior
Shear Force
Reference Test
Conference
Euromech Colloquim 556 Theoretical Numerical and Experimental Analyses of Wood Mechanics
Research Status
Complete
Notes
May 2015, Dresde, Germany
Summary
Cross Laminated Timber (CLT) panels are more and more common in timber construction. When submitted to out-of-plane loads, they can be considered as multi-layer plates with anisotropic behaviour. Their main structural issue is the low transverse shear strength of cross layers which leads to rolling shear failure. In addition the fabrication process can include or not lateral boards’ gluing. The resulting discontinuities can be considered as weakly heterogeneous and influence the mechanical response. Moreover the timber construction market requires new technical solutions for CLT, like periodic voids within the panel. This solution leads to lighter and more thermally efficient floors. However, the spaced voids between boards increase the heterogeneity of the panel and therefore the complexity of stresses’ distribution.
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Advanced Wood-Based Solutions for Mid-Rise and High-Rise Construction: Proposed Vibration-Controlled Design Criterion for Supporting Beams

https://research.thinkwood.com/en/permalink/catalogue1178
Year of Publication
2018
Topic
Acoustics and Vibration
Mechanical Properties
Application
Floors
Author
Hu, Lin
Organization
FPInnovations
Year of Publication
2018
Format
Report
Application
Floors
Topic
Acoustics and Vibration
Mechanical Properties
Keywords
Floor Supporting Beam
Bending Stiffness
Research Status
Complete
Summary
For wood floor systems, their vibration performance is significantly dependent on the conditions of their supports, specifically the rigidity of the support. Detrimental effects could result if the floor supports do not have sufficient rigidity. This is special ture for floor supporting beams. The problem of vibrating floor due to flexible supporting beams can be solved through proper design of the supporting beams. However, there is currently no criterion set for the minimum requirement for floor supporting beam stiffness to ensure the beam is rigid enough. Designers’ current practice is to use the uniform load deflection criteria specified in the code for designing the supporting beams. This criterion is based on certain ratios of the floor span (e.g. L/360, L/480 etc.). The disadvantage of this approach is that it allows larger deflections for longer-span beams than for shorter beams. This means that engineers have to use their experience and judgement to select a proper ratio, particularly for the long-span beams. Therefore, a better vibration-controlled design criterion for supporting beams is needed. It is recommended to further verify the ruggedness of the proposed stiffness criterion for floor supporting beams using new field supporting beam data whenever they become available.
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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
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
Research Status
Complete
Series
Proceedings of the Institution of Civil Engineers - Construction Materials
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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Analysis of Rotational Stiffness of the Timber Frame Connection

https://research.thinkwood.com/en/permalink/catalogue2763
Year of Publication
2020
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Johanides, Marek
Kubíncová, Lenka
Mikolášek, David
Lokaj, Antonín
Sucharda, Oldrich
Mynarcík, Petr
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Connections
Keywords
Rotational Stiffness
Frame Connection
Screw
Numerical Model
FEM
Finite Element Model
Mechanical Fasteners
Research Status
Complete
Series
Sustainability
Summary
Initially, timber was considered only as an easily accessible and processable material in nature; however, its excellent properties have since become better understood. During the discovery of new building materials and thanks to new technological development processes, industrial processing technologies and gradually drastically decreasing forest areas, wood has become an increasingly neglected material. Load-bearing structures are made mostly of reinforced concrete or steel elements. However, ecological changes, the obvious problems associated with environmental pollution and climate change, are drawing increasing attention to the importance of environmental awareness. These factors are attracting increased attention to wood as a building material. The increased demand for timber as a building material offers the possibility of improving its mechanical and physical properties, and so new wood-based composite materials or new joints of timber structures are being developed to ensure a better load capacity and stiffness of the structure. Therefore, this article deals with the improvement of the frame connection of the timber frame column and a diaphragm beam using mechanical fasteners. In common practice, bolts or a combination of bolts and pins are used for this type of connection. The subject of the research and its motivation was to replace these commonly used fasteners with more modern ones to shorten and simplify the assembly time and to improve the load capacity and rigidity of this type of frame connection.
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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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Analytical Procedure for Timber-Concrete Composite (TCC) System with Mechanical Connectors

https://research.thinkwood.com/en/permalink/catalogue3119
Year of Publication
2022
Topic
Design and Systems
Material
Timber-Concrete Composite
Application
Floors
Author
Mirdad, Md Abdul Hamid
Khan, Rafid
Chui, Ying Hei
Organization
University of Illinois at Urbana-Champaign
University of Alberta
Editor
Tullini, Nerio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
Timber-Concrete Composite
Application
Floors
Topic
Design and Systems
Keywords
Mechanical Connectors
Progressive Yielding
Effective Bending Stiffness
Deflection
Vibration
Research Status
Complete
Series
Buildings
Summary
In the construction of modern multi-storey mass timber structures, a composite floor system commonly specified by structural engineers is the timber–concrete composite (TCC) system, where a mass timber beam or mass timber panel (MTP) is connected to a concrete slab with mechanical connectors. The design of TCC floor systems has not been addressed in timber design standards due to a lack of suitable analytical models for predicting the serviceability and safety performance of these systems. Moreover, the interlayer connection properties have a large influence on the structural performance of a TCC system. These connection properties are often generated by testing. In this paper, an analytical approach for designing a TCC floor system is proposed that incorporates connection models to predict connection properties from basic connection component properties such as embedment and withdrawal strength/stiffness of the connector, thereby circumventing the need to perform connection tests. The analytical approach leads to the calculation of effective bending stiffness, forces in the connectors, and extreme stresses in concrete and timber of the TCC system, and can be used in design to evaluate allowable floor spans under specific design loads and criteria. An extensive parametric analysis was also conducted following the analytical procedure to investigate the TCC connection and system behaviour. It was observed that the screw spacing and timber thickness remain the most important parameters which significantly influence the TCC system behaviour.
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An Evaluation of Strength Performance of the Edge Connections between Cross-laminated Timber Panels Reinforced with Glass Fiber-reinforced Plastic

https://research.thinkwood.com/en/permalink/catalogue2424
Year of Publication
2019
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems

An experimental study of the stiffness and strength of cross-laminated timber wall-to-floor connections under compression perpendicular to the grain

https://research.thinkwood.com/en/permalink/catalogue3197
Year of Publication
2022
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Author
Schweigler, Michael
Akter, Shaheda T.
Sabaa, Stephen
Bader, Thomas K.
Organization
Linnaeus University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Topic
Connections
Keywords
Compression Perpendicular To Grain
Stress Dispersion
Nominal Stiffness
Nominal Strength
Digital Image Correlation
Research Status
Complete
Series
Engineering Structures
Summary
In platform-type multi-story cross-laminated timber (CLT) buildings, gravity loads from upper floors, and vertical reaction forces from horizontal actions, like wind loads, cause substantial compressive forces in the CLT-floor elements. The combination of these high forces with a comparable low compression stiffness and strength perpendicular to the grain of timber, makes the compression perpendicular to the grain (CPG) verification of CLT an important design criterion. In this experimental study, CPG of CLT was investigated by means of typical wall-to-floor connections in CLT platform-type structures. CLT-wall elements were used for load application to transmit forces through the CLT-floor element by CPG. Compared to load application by steel elements, as it commonly is done in experiments, lower stiffness but similar strength were found for CLT walls. The study of different connection types showed the highest stiffness and strength for connections assembled with screws, followed by pure wood-to-wood contact, while connections with acoustic layers between the floor and wall elements showed the lowest stiffness and strength. In addition, these connections were tested for center and edge load position on the CLT-floor element. The strength for center and edge position compared to full surface loaded specimens increased linearly with the activated material volume, as determined by earlier proposed stress dispersion models. The stress dispersion effect was visualized by surface strain measurements using digital image correlation technique. Also, the stiffness increased with the activated material volume. Stress dispersion in the CLT-floor allowed to explain the increase in stiffness and strength with decreasing CLT-wall thickness. Strength values at different strain levels, and stiffness and strength increase factors suitable for the engineering design of CLT structures are provided.
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An Improved Model for the Fire Design of Cross Laminated Timber in Bending

https://research.thinkwood.com/en/permalink/catalogue1940
Year of Publication
2018
Topic
Fire
Material
CLT (Cross-Laminated Timber)
Author
Schmid, Joachim
Klippel, Michael
Fahrni, Reto
Frangi, Andrea
Tiso, Mattia
Just, Alar
Werther, Norman
Organization
ETH Zurich
Tallinn University of Technical
Technical University Munich
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Fire
Keywords
Fire Resistance
Model
Zero-Strength Layer
Cross-Section
Bending
Strength
Stiffness
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 20-23, 2018, Seoul, Republic of Korea
Summary
In this study, new design models for cross-laminated timber (CLT) are developed to verify the fire resistance up to 120 minutes. This is done aiming for the popular Effective Cross-Section Method using a so-called zero-strength layer (ZSL) to account for losses in strength and stiffness. This was done using a method earlier presented at WCTE 2010 and discussed with the European industry. To allow for improvements, (a) the current CLT product portfolio was analysed and thermal and mechanical simulations were done accordingly for initially unprotected and unprotected members. Further, (b) new definitions for the ZSL were used to allow for a higher accuracy of the simplified models. As anoutcome, a model with (1) tabulated data between 7.0 and 12.0 mm for the effective ZSL only considering longitudinal layers and (2) a simplified model “twelve and two” is proposed for CLT members in bending.
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Application of Modern Wood Product Glulam in Timber Frame with Tenon- Mortise Joints and its Structural Behavior

https://research.thinkwood.com/en/permalink/catalogue2469
Year of Publication
2019
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)

211 records – page 1 of 22.