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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
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Design of Shear Reinforcement for Timber Beams

https://research.thinkwood.com/en/permalink/catalogue1109
Year of Publication
2013
Topic
Connections
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Dietsch, Philipp
Kreuzinger, Heinrich
Winter, Stefan
Year of Publication
2013
Country of Publication
Germany
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Design and Systems
Keywords
Shear
Reinforcement
Fractured
Unfractured
Language
English
Conference
CIB-W18 Meeting
Research Status
Complete
Notes
August 26-29, 2013, Vancouver, Canada p.193-209
Summary
The use of glulam beams with changing depth offers the possibility to adapt the section modulus to the bending moment. In the case of single-span beams under uniformly distributed load, however, a change in beam depth will lead to a contrary effect for the shear stresses, see Figure 1. Curved and pitched cambered beams feature not only high utilization rates in bending but also areas of high tension stresses perpendicular to the grain and shear parallel to the grain stresses, two stress components for which timber features only small capacities as well as brittle failure modes. Out of 245 cases of damaged or failed large-span timber structures, evaluated in [1], several failures document the possibility of a shear fracture (full separation) developing in grain direction from the curved part towards the supports, partly followed by a failure of the beam in flexural tension due to a change in stress distribution resulting from the change in section modulus. Reinforcements against tension stresses perpendicular to the grain in form of fully threaded screws or threaded rods can be considered state of the art [2], [3]. With respect to their application as shear reinforcement, not many research results are yet available [4], [5], resulting in a lack of experimentally validated design approaches. Within this paper, approaches to design shear reinforcement for glulam beams in the unfractured and the fractured state are presented, validated and discussed. The moment of failure, i.e. the transition from the unfractured to the fractured state is characterized by dynamic effects. This situation is not covered in this paper. A possible approach is given in [1]. The same applies to the subject of moisture induced stresses, resulting from the reinforcement restricting the free shrinkage or swelling of the glulam beam.
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Fully Reversible Reinforcement of Softwood Beams with Unbonded Composite Plates

https://research.thinkwood.com/en/permalink/catalogue210
Year of Publication
2016
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Borri, Antonio
Speranzini, Emanuela
Castori, Giulio
Corradi, Marco
Publisher
ScienceDirect
Year of Publication
2016
Country of Publication
Netherlands
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Failure
Flexural Tests
Glass Fiber Reinforced Polymer
Modulus of Rupture
Reinforcement
Softwood
finite element method
Numerical model
Language
English
Research Status
Complete
Series
Composite Structures
Summary
In this paper, results of flexure tests aimed at improving the structural behavior of softwood beams reinforced with unglued composite plates and at developing an effective alternative to the use of organic resins are presented. The addition of modest ratios of GFRP (Glass Fiber Reinforced Polymer) composite strengthening can prevent tension failure in timber beams. However the application of organic matrices presents problems of reversibility, compatibility and durability with timber and poor performance at high temperatures. The increment in capacity and stiffness and the analysis of the failure modes is the central focus of this paper. The experimental campaign is dealing with a significant number of un-reinforced and reinforced beams strengthened with unbonded GFRP plates. A 3-dimensional finite element model is also presented for simulating the non-linear behavior of GFRP-reinforced softwood beams. The ability of the numerical model to reproduce experimental results for the load–deflection curves is validated.
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An Analytical Model for Design of Reinforcement around Holes in Laminated Veneer Lumber (LVL) Beams

https://research.thinkwood.com/en/permalink/catalogue135
Year of Publication
2013
Topic
Design and Systems
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Ardalany, Manoochehr
Fragiacomo, Massimo
Moss, Peter
Deam, Bruce
Publisher
Springer Netherlands
Year of Publication
2013
Country of Publication
Netherlands
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Failure
Glued-In Rods
Model
Reinforcement
Screws
Tensile
Language
English
Research Status
Complete
Series
Materials and Structures
ISSN
1871-6873
Summary
Openings are usually required to allow services like plumbing, sewage pipes and electrical wiring to run through beams. This prevents an extra depth of the floor/ceiling, while preserving architectural considerations. The introduction of large opening causes additional tension perpendicular to grain in timber beams. The low tensile strength perpendicular to grain of wood allows crack formation. Crack propagation around the hole considerably decreases the load-carrying capacity of the beam. However, in most cases, crack formation and propagation around the hole can be prevented by the use of an appropriate reinforcement. Screw, glued-in rods, and plywood are alternative options for the reinforcement. Design of the reinforcement requires that the working mechanism of the reinforcement is fully understood and properly addressed. In addition, reinforcement should be designed for actions produced in the section of the beam weakened by the hole. The current paper uses a simple truss model around the opening to calculate the tensile force in the reinforcement. Two simple formulations for design of the reinforcement are derived and compared with numerical and experimental results, showing an overall good correspondence. The proposed truss model can be considered for incorporation in future codes of practice.
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Timber-Concrete Composite Bridges: State-of-the-Art Review

https://research.thinkwood.com/en/permalink/catalogue2125
Year of Publication
2013
Topic
Design and Systems
General Information
Material
Timber-Concrete Composite
Application
Bridges and Spans

State-of-the-Art Review of Displacement-Based Seismic Design of Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2123
Year of Publication
2018
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Author
Loss, Christiano
Tannert, Thomas
Tesfamariam, Solomon
Publisher
Elsevier
Year of Publication
2018
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Light Frame (Lumber+Panels)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Keywords
Performance Based Design
Direct Displacement-Based Design
Hybrid Structures
N2 Method
Design Procedures
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
This paper discusses the state-of-the-art of displacement-based seismic design (DBD) methods and their applications to timber buildings. First, an in-depth review of the DBD methods is presented, focusing in particular on the direct, modal and N2 methods. Then, paper presents DBD application on a wide range of construction systems, including both traditional light-frame structures as well as the emerging sector of tall and hybrid timber buildings. Finally, potentials of using these DBD methods for seismic design as well as possible implications of including DBD within the next generation of building codes are discussed.
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Free
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Encapsulated Mass Timber Construction: Guidelines for Encapsulation Details and Techniques

https://research.thinkwood.com/en/permalink/catalogue2600
Year of Publication
2019
Topic
Design and Systems
Fire
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Wood Building Systems
Author
Ranger, Lindsay
Geraghty, Simon
Jeske, Judy
Rahmani, Alma
Dorsey, Cheryl
Organization
FPInnovations
Year of Publication
2019
Country of Publication
Canada
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
DLT (Dowel Laminated Timber)
Glulam (Glue-Laminated Timber)
NLT (Nail-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Fire
Keywords
Encapsulated Mass Timber Construction
EMTC
Fire Protection
Construction Safety
Language
English
Research Status
Complete
Summary
The purpose of this guide is to provide an introduction to the concept of encapsulated mass timber construction. This guide provides an overview of encapsulation techniques for mass timber construction, and other related fire protection measures, and summarizes some approved encapsulation materials and application methods and identifies additional requirements for safety during construction. This guide is intended to help architects, engineers and designers by reducing uncertainty and allowing for more confidence in design, as well as providing authorities having jurisdiction and inspectors with a reference for simple design review.
Online Access
Free
Resource Link
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Modeling Techniques for Post-tensioned Cross-laminated Timber Rocking Walls

https://research.thinkwood.com/en/permalink/catalogue2396
Year of Publication
2019
Topic
Seismic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Walls

Bamboo Reinforced Glulam Beams: An Alternative to CFRP Reinforced Glulam Beams

https://research.thinkwood.com/en/permalink/catalogue640
Year of Publication
2013
Topic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Echavarria, Cesar
Echavarría, Beatriz
Cañola, Hernán
Publisher
Scientific.net
Year of Publication
2013
Country of Publication
Switzerland
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Keywords
Bamboo
CFRP
Load-Deformation
Reinforcement
Stiffness
Strength
Language
English
Research Status
Complete
Series
Advanced Materials Research
Summary
A research study was undertaken to investigate the mechanical performance of glulam beams reinforced by CFRP or bamboo. Local reinforcement is proposed in order to improve the flexural strength of glulam beams. The glulam beam is strengthened in tension and along its sides with the carbon fiber-reinforced polymer CFRP or bamboo. A series of CFRP reinforced glulam beams and bamboo reinforced glulam beams were tested to determine their load-deformation characteristics. Experimental work for evaluating the reinforcing technique is reported here. According to experiment results, the CFRP and bamboo reinforcements led to a higher glulam beam performance. By using CFRP and bamboo reinforcements several improvements in strength may be obtained.
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Free
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Glued Timber-Concrete Beams – Analytical and Numerical Models for Assessment of Composite Action

https://research.thinkwood.com/en/permalink/catalogue154
Year of Publication
2013
Topic
Design and Systems
Serviceability
Material
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Beams
Author
Skec, Leo
Bjelanovic, Adriana
Jelenic, Gordan
Publisher
HRCAK
Year of Publication
2013
Country of Publication
Croatia
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Beams
Topic
Design and Systems
Serviceability
Keywords
Finite Element Model
Load Carrying Capacity
Loading
Numerical models
Short-term
Language
English
Research Status
Complete
Series
Engineering Review
Summary
An analysis of glued composite timber-concrete systems is presented. Experimental data obtained from laboratory tests under short-term loading are compared with the analytical calculation and the design procedure for fully composite beams given in the EN 1995-1-1 standard. Numerical linear 2D finite element modelling and an analytical solution assuming linear elastic behaviour of glue and the interlayer slip are also conducted and validated. The effect of composite action in the three mentioned approaches is assessed by comparison of midspan deflections. In this way, a parametric study of the glue-line properties and the interlayer slip stiffness on load-carrying capacity and serviceability of glued composite beams exposed to short-time loading is easily performed.
Online Access
Free
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10 records – page 1 of 1.