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A New Approach to Classify the Degree of Combustibility of Materials

https://research.thinkwood.com/en/permalink/catalogue2257
Topic
Fire
Organization
Université Laval
Country of Publication
Canada
Topic
Fire
Keywords
Fire Safety
Combustion Properties
Heat Flux
Numerical Modeling
Cone Calorimeter Testing
Flame Spread
Research Status
In Progress
Notes
Project contact is Christian Dagenais at Université Laval
Summary
The use of materials in a building is traditionally determined from its combustibility (via ULC S114 or ULC S135) and by its flame propagation index (via ULC S102). The ULC S102 Flame Spread Test, developed in 1943, has historically reduced risk through its method of classifying materials. However, this test does not provide quantitative information on the combustion properties of materials, such as heat flow. The latter is one of the most important variables in the development of a fire. Thus, a new approach would be preferable in order to review the classification of materials according to ULC S102 and ULC S135 (cone calorimeter). The objective of this project is to develop a new approach to classifying materials based on cone calorimeter test results. These results can subsequently be used in numerical modeling as part of a fire safety engineering design. A significant amount of cone calorimeter (ULC S135) testing of materials currently evaluated according to ULC S102 will be required.
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A Numerical 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/catalogue2839
Year of Publication
2021
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Akter, Shaheda
Schweigler, Michael
Serrano, Erik
Bader, Thomas
Organization
Linnaeus University
Lund University
Editor
Brandner, Reinhard
Publisher
MDPI
Year of Publication
2021
Country of Publication
Sweden
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Connections
Mechanical Properties
Keywords
Parametric Study
Perpendicular to the Grain
Elasto-Plastic Behaviour
Numerical Modeling
Language
English
Research Status
Complete
Series
Buildings
Summary
The use of cross-laminated timber (CLT) in multi-story buildings is increasing due to the potential of wood to reduce green house gas emissions and the high load-bearing capacity of CLT. Compression perpendicular to the grain (CPG) in CLT is an important design aspect, especially in multi-storied platform-type CLT buildings, where CPG stress develops in CLT floors due to loads from the roof or from upper floors. Here, CPG of CLT wall-to-floor connections are studied by means of finite element modeling with elasto-plastic material behavior based on a previously validated Quadratic multi-surface (QMS) failure criterion. Model predictions were first compared with experiments on CLT connections, before the model was used in a parameter study, to investigate the influence of wall and floor thicknesses, the annual ring pattern of the boards and the number of layers in the CLT elements. The finite element model agreed well with experimental findings. Connection stiffness was overestimated, while the strength was only slightly underestimated. The parameter study revealed that the wall thickness effect on the stiffness and strength of the connection was strongest for the practically most relevant wall thicknesses between 80 and about 160 mm. It also showed that an increasing floor thickness leads to higher stiffness and strength, due to the load dispersion effect. The increase was found to be stronger for smaller wall thicknesses. The influence of the annual ring orientation, or the pith location, was assessed as well and showed that boards cut closer to the pith yielded lower stiffness and strength. The findings of the parameter study were fitted with regression equations. Finally, a dimensionless ratio of the wall-to-floor thickness was used for deriving regression equations for stiffness and strength, as well as for load and stiffness increase factors, which could be used for the engineering design of CLT connections.
Online Access
Free
Resource Link
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Post-Tensioned Timber Frame Structures

https://research.thinkwood.com/en/permalink/catalogue63
Year of Publication
2015
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Columns
Author
Wanninger, Flavio
Organization
ETH Zurich
Year of Publication
2015
Country of Publication
Switzerland
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Columns
Topic
Connections
Keywords
Moment Resistance
Economical
Timber Joints
Moment-Rotation
Bending Test
Pushover Test
Numerical Modeling
Language
English
Research Status
Complete
Summary
The present research report was written as a PhD thesis (ETH Dissertation Nr. 22815) by Flavio Wanninger and shows the results of a comprehensive experimental and numerical analysis on the structural behaviour of post-tensioned timber frame, in particular with focus on the momentrotation-behaviour of the developed post-tensioned beam-column timber joint using hardwood and the long-term behaviour of the system. The results of the experimental and numerical investigations provide reliable data for the development and validation of calculation models for the design of post-tensioned timber frames with hardwood for vertical and horizontal loads and taking into account the long-term behaviour. The objective of the research project is the development and implementation of post-tensioned timber frame structures into the practice and fits well into the overall research strategy of the institute on the development of innovative solutions for timber structures.
Online Access
Free
Resource Link
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Proposal for a Standardized Design and Modeling Procedure of Tall CLT Buildings

https://research.thinkwood.com/en/permalink/catalogue1219
Year of Publication
2016
Topic
Design and Systems
Seismic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Polastri, Andrea
Pozza, Luca
Publisher
University of Kragujevac
Year of Publication
2016
Country of Publication
Montenegro
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Connections
Keywords
Stiffness
Numerical Modeling
Language
English
Research Status
Complete
Series
International Journal for Quality Research
ISSN
1800-7473
Summary
A crucial issue in the design of a mid-rise Cross Laminated Timber (CLT) building under horizontal seismic action, is the definition of the principal elastic vibration period of an entire superstructure. Such vibration period depends on the mass distribution and on the global stiffness of the buildings. In a CLT structure the global stiffness of the buildings is highly sensitive to deformability of the connection elements. Consequently for a precise control of the vibration period of the building it is crucial to define the stiffness of each connections used to assemble a superstructure. A design procedure suitable for a reliable definition of the connection stiffness is proposed referring to code provisions and experimental tests. Discussion addresses primary issues associated with the usage of proposed procedure for numerical modeling of case study tall CLT buildings is reported.
Online Access
Free
Resource Link
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