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Finite Element Modelling of Heat and Moisture Transfer through Cross Laminated Timber Panels

https://research.thinkwood.com/en/permalink/catalogue2414
Year of Publication
2019
Topic
Moisture
Fire
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
Application
Wood Building Systems
Walls

Modelling of Heat Transfer in Timber Exposed to Fire

https://research.thinkwood.com/en/permalink/catalogue1683
Year of Publication
2016
Topic
Fire
Material
LVL (Laminated Veneer Lumber)
Author
Diem Thi, Van
Khelifa, Mourad
El Ganaoui, Mohammed
Rogaume, Yann
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Fire
Keywords
Numerical Model
Heat Transfer
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4069-4076
Summary
This paper presents a numerical model for heat transfer in timber structures. The thermal behaviour is described by the standard Fourier heat equation. The chosen model integrates the three modes of heat transfer; namely: conduction, radiation and convection during the fire exposure. The theory and the boundary conditions associated with the model are briefly discussed. The identification of the model parameters is carried out with the experimental data available in literature. The simulation results are compared with experiments carried out on laminated veneer lumber (LVL) panels.
Online Access
Free
Resource Link
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Analysis of Shear Transfer and Gap Opening in Timber–Concrete Composite Members with Notched Connections

https://research.thinkwood.com/en/permalink/catalogue1399
Year of Publication
2017
Topic
Connections
Mechanical Properties
Material
Timber-Concrete Composite
Author
Boccadoro, Lorenzo
Steiger, René
Zweidler, Simon
Frangi, Andrea
Publisher
Springer Netherlands
Year of Publication
2017
Country of Publication
Netherlands
Format
Journal Article
Material
Timber-Concrete Composite
Topic
Connections
Mechanical Properties
Keywords
Notched Connections
Analytical Model
Shear Stress
Failure
Language
English
Research Status
Complete
Series
Materials and Structures
ISSN
1871-6873
Summary
In timber–concrete composite members with notched connections, the notches act as the shear connections between the timber and the concrete part, and have to carry the shear flow necessary for composite action. The shear transfer through the notches generates shear and tensile stresses in both parts of the composite member, which may lead to brittle failure and to an abrupt collapse of the structure. Although simplified design formulas already exist, some structural aspects are still not clear, and a reliable design model is missing. This paper summarizes current design approaches and presents analytical models to understand the shear-carrying mechanism, to estimate the shear stresses acting in the timber and concrete, and to predict failure. The analysis concentrates on three problems: the shearing-off failure of the timber close to the notch, the shear failure of the concrete, and the influence of the shear flow on the gap opening between the timber and concrete. Parts of the model calculations could be compared to experimental observations. The conclusions of this paper contribute to improving current design approaches.
Online Access
Free
Resource Link
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Heat Transfer Tests on EPS Material and Massive Timber Wall Component

https://research.thinkwood.com/en/permalink/catalogue2224
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls

Numerical Modeling of Mass Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2283
Year of Publication
2018
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Hollenbeck, Sean
Publisher
Oregon State University
Year of Publication
2018
Country of Publication
United States
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Keywords
Finite Element Analysis
Abaqus
Single Nail Model
Language
English
Research Status
Complete
Online Access
Free
Resource Link
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Experimental Investigation on the Fire Resistance of Glued-In Rod Timber Joints with Heat Resistant Modified Epoxy Resin

https://research.thinkwood.com/en/permalink/catalogue2665
Year of Publication
2020
Topic
Fire
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Luo, Liquan
Shi, Benkai
Liu, Weiqing
Yang, Huifeng
Ling, Zhibin
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Connections
Keywords
Fire Resistance
Glued-In Rod Joint
Glued-In Rod Timber Joint
Pull-Out Test
Heat Resistant
Modified Epoxy Resin
Adhesive
Language
English
Research Status
Complete
Series
Materials
Summary
This paper presents an experimental evaluation of the fire resistance of glued-in rod timber joints using epoxy resin, with and without modification. A heat-resistant modified resin was designed by adding inorganic additives into the epoxy resin, aiming to improve the heat resistance. Joints that were made using the modified epoxy resin at room temperature showed a bearing capacity comparable to those with commercial epoxy resin. Twenty-one joint specimens with the modified epoxy resin and six with a commercial epoxy resin were tested in a fire furnace to evaluate the fire resistance. The main failure mode was the pull-out of the rod, which is typical in fire tests of this type of joints. As to the effects of the test parameters, this study considered the effects of adhesive types, sectional sizes, stress levels, and fireproof coatings. The test results showed that the fire resistance period of a joint can be evidently improved by modifying the resin and using the fireproof coating, as the improvements reached 73% and 35%, respectively, compared with the joint specimens with commercial epoxy resin. It was also found that, for all specimens, the fire resistance period decreased with an increase in the stress level and increased with an increase in the sectional sizes.
Online Access
Free
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A Method to Characterize Biological Degradation of Mass Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2724
Year of Publication
2020
Topic
Connections
Serviceability
Material
CLT (Cross-Laminated Timber)
Author
Sinha, Arijit
Udele, Kenneth
Cappellazzi, Jed
Morrell, Jeff
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Serviceability
Keywords
Biological Durability
Fungal Degradation
Fungus
Connection Strength
Language
English
Research Status
Complete
Series
Wood and Fiber Science
Summary
Biological durability issues in cross-laminated timber (CLT) have been majorly ignored in North America because of the European origin of the material and careful construction practices in Europe. However, the risks of fungal and insect attacks are increased by the North American climatic conditions and lack of job-site measures to keep the material dry. The methods to evaluate durability in solid timber are inadequate for use in mass timber (MT) for a number of reasons, such as moisture variation and size being critical issues. This study therefore proposes a method, which is suitable to evaluate the strength of MT assemblies that are exposed to fungal degradation. The objective of the study was to explore a controlled method for assessing the effects of wetting and subsequent fungal attack on the behavior of CLT connections. Two different methods were used to create fungal attack on CLT assemblies. Although they were both successful, one was cumbersome, left room for many errors, and was not as efficient as the other. In addition, a standardized method to evaluate and characterize key performance metric for the connections is presented.
Online Access
Free
Resource Link
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Deconstructable Hybrid Connections for the Next Generation of Prefabricated Mass Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2809
Year of Publication
2021
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Hybrid Building Systems
Shear Walls
Author
Shulman, Samuel
Loss, Cristiano
Organization
University of British Columbia
Year of Publication
2021
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Floors
Hybrid Building Systems
Shear Walls
Topic
Connections
Keywords
Steel Rods
Epoxy
Push-Out-Shear Tests
Prefabrication
Disassembly
Reuse
Language
English
Research Status
Complete
Summary
Timber has been used for building construction for centuries, until the industrial revolution, when it was often replaced by steel and concrete or confined to low-rise housings. In the last thirty years however, thanks to the development of mass timber products and new global interest in sustainability, timber has begun to make a resurgence in the building industry. As building codes and public perception continues to change, the demand for taller and higher-performance timber buildings will only grow. Thus, a need exists for new construction technology appropriate for taller mass timber construction, as well as for fabrication and deconstruction practices that respect wood’s inherent sustainable nature. With this in mind, this research program aims to develop a new hybrid shear connection for mass timber buildings that allows for easy construction, deconstruction, and reuse of the structural elements. This report includes results of Phase 1, which focused on connections consisting of partially threaded 20M and 24M steel rods bonded into pockets formed in CLT and surrounded by thick crowns of high-strength three-component epoxy-based grout. A total of 168 specimens were designed and fabricated, and push-out shear tests carried out with a displacement-controlled monotonic loading protocol. Strength and stiffness values were assessed and effective failure modes in specimens identified. These latter, along with the recorded load-deformation curves, indicate that it is possible to develop mechanics-based design models and design formulas akin to those already used for typical dowel-type fastener timber connections. Additionally, the specimens were easily fabricated in the lab and quickly fastened to the test jig by means of nuts and washers, suggested such connections have a strong potential for prefabrication, disassembly, and reuse.
Online Access
Free
Resource Link
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Deconstructable Hybrid Connections for the Next Generation of Mass Timber Prefabricated Buildings

https://research.thinkwood.com/en/permalink/catalogue2551
Topic
Connections
Application
Hybrid Building Systems
Country of Publication
Canada
Application
Hybrid Building Systems
Topic
Connections
Keywords
Deconstructable Connections
Prefabrication
Modular Construction
Reuse
Seismic Resistance
Research Status
In Progress
Notes
Project contact is Cristiano Loss at the University of British Columbia
Summary
This research aims at developing novel multi-material deconstructable hybrid connections for mass timber prefabricated buildings. Connections will be conceived in order to (i) meet multi-objective structural performance, (ii) favour modular construction, (iii) favour quick erection of buildings, (iv) quick disassemble and possible reuse of the timber members, and (v) provide seismic-resistant structural assemblies.
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Towards Resilient Mass Timber Systems: Understanding Durability of Cross-Laminated Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2293
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Organization
Oregon State University
Portland State University
Country of Publication
United States
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Keywords
Durability
Mass Timber
Moisture
Ultrasonic
Cyclic Loading Tests
Research Status
In Progress
Notes
Project contact is Arijit Sinha.
Summary
Cross Laminated Timber (CLT) is gaining acceptance in tall building applications in the US. However, there are knowledge gaps concerning long-term performance, particularly effects due to moisture intrusion and biological decay in relation to connection systems. In a risk-averse industry, this knowledge gap impedes acceptance of CLT. The overall goal of the project is to characterize the effects of moisture accumulation in mass timber buildings on properties of building components and connections. The project will assess CLT connectors using small-scale assemblies, then use these data to develop predictive models that will be compared with full-scale tests. Connection assemblies will be constructed with two wood species and exposed to five moisture/biological regimes. Moisture behavior in the assemblies will be characterized using a combination of non-destructive tools, such as ultrasonic, wave propagation, CAT-Scan, and infrared imaging. The data generated from cyclic loading tests will be used to calibrate the SAWS connection model. This will provide a novel way to estimate the effects of moisture and biological degradation on connections. A deliverable for this project is a design guideline for engineers to account for the effects of moisture intrusion and subsequent fungal decay on panel and connection properties.
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10 records – page 1 of 1.