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50 records – page 1 of 5.

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
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
Research Status
Complete
Series
Materials and Structures
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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Application of Ductile Yield Link in Glulam Moment Connections

https://research.thinkwood.com/en/permalink/catalogue2313
Year of Publication
2018
Topic
Connections
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Beams

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
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Keywords
Bamboo
CFRP
Load-Deformation
Reinforcement
Stiffness
Strength
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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Comparison of Glulam Post-To-Beam Connections Reinforced by two Different Dowel-Type Fasteners

https://research.thinkwood.com/en/permalink/catalogue55
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
He, Minjuan
Liu, Hui-Fen
Publisher
ScienceDirect
Year of Publication
2015
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Reinforcement
Rods
Seismic
Self-Tapping Screws
Moment Resistance
Research Status
Complete
Series
Construction and Building Materials
Summary
In this paper, the performance improvement of glulam post-to-beam connections reinforced by plain round rods (PRRs) and self-tapping screws (STSs) were compared. Five non-reinforced post-to-beam bolted connections, five PRR-reinforcing connections and five STS-reinforcing connections were experimentally investigated under monotonic and low frequency cyclic loading. Their stiffness, ductility, moment resistance capacity, failure modes and seismic behavior were analyzed. The findings indicated that both of these two reinforcements could mitigate wood splitting, and change the failure mode from brittle failure to ductile failure. The maximum moment and failure rotation of PRR-reinforcing connection were increased by 29% and 6% respectively, compared with those of non-reinforced connection. In addition, those of STS-reinforcing connection increased by 86% and 145% respectively. Furthermore, the comparison of PRR-reinforcing and STS-reinforcing connections indicated that the connection ductility reinforced by self-tapping screws enhanced more significantly; 106% higher than that of PRR-reinforcing connection. Moreover, under the low frequency cyclic loading, PRR-reinforcing and STS-reinforcing connections dissipated more energy (336% and 641% respectively) with a lower stiffness degeneration rate and a higher equivalent viscous damping ratio than those of non-reinforced connection. Besides, the dissipation energy and equivalent viscous damping ratio of STS-reinforcing connection were larger than those of PRR-reinforcing connection.
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Comparison of Verification and Reinforcement Concepts for Timber Beams with Large Round Holes

https://research.thinkwood.com/en/permalink/catalogue1714
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Dröscher, Julia
Augustin, Manfred
Schickhofer, Gerhard
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Reinforcement
Shear Stresses
Tensile Stresses
Load Carrying Capacity
Numerical Investigation
Analytical Investigation
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4529-4538
Summary
Within this paper a comparison of different reinforcement concepts for timber beams with round holes is carried out. Therefore currently applied standardized methods and two recently developed approaches are considered. By means of numerical and analytical investigations it becomes apparent that the analysed reinforcement methods divergent to those given in current standards have great potential: shear stresses as well as tensile stresses perpendicular to the grain in the critical areas around the beam opening can be reduced significantly. Hence, the maximum load carrying capacities of the new reinforcement concepts supposedly exceed the standardized ones considerably. For verification of the results experimental investigations on beams with different reinforcement methods are planned.
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Cross Laminated Timber (CLT) Plane Structures Under Concentrated Loading from Point Supports - Shear Design including Reinforcements

https://research.thinkwood.com/en/permalink/catalogue1572
Year of Publication
2011
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Mestek, Peter
Organization
Technical University of Munich
Year of Publication
2011
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Mechanical Properties
Keywords
Point-Supported
Concentrated Loads
Shear
Rolling Shear
Reinforcement
Screws
Biaxial
Research Status
Complete
Summary
This thesis deals with the shear design of Cross Laminated Timber (CLT) elements stressed by concentrated loads which are locally reinforced by means of self-tapping screws with continuous threads. A simplified model is presented using an effective width for the calculation of the shear stresses in the vicinity of point supports or concentrated loads. Laboratory tests supply material-mechanical principles to determine the interaction of rolling shear stresses and compression perpendicular to the grain. In addition to experimental tests theoretical models are developed to examine the load bearing behaviour of CLT-elements reinforced by self-tapping screws. Preliminary tests with plate elements provide initial experience with these reinforcements under biaxial load transfer. Finally a design concept validated by means of the test results is proposed.
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Cross Laminated Timber under Concentrated Compression Loads - Methods of Reinforcement

https://research.thinkwood.com/en/permalink/catalogue2932
Year of Publication
2021
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Maurer, Bernhard
Maderebner, Roland
Organization
University of Innsbruck
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Keywords
Multi-storey Buildings
Point-supported Flat Slabs
Reinforcement
System Connector
SPIDER Connector
Punching Test
Research Status
Complete
Series
Engineering Structures
Summary
Point-supported flat slabs made of cross laminated timber (CLT) for multi-storey buildings pose various challenges to structural timber design. One aspect are concentrated compressive loads, which cause stress concentrations in the form of shear and compression perpendicular to the grain at the point supports. The present work deals with this problem and shows a method, how the support area can be reinforced with a system connector. After a specification of the connector, the functionality of this construction element is described on the basis of experimental, numerical and analytical studies for a symmetrical loading. The interaction of the connector with the (CLT) is presented with an anlaytical model and numerical simulations, and evaluated with mechanical tests.
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Deformability of Glued Laminated Beams with Combined Reinforcement

https://research.thinkwood.com/en/permalink/catalogue2835
Year of Publication
2020
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Sobczak-Piastka, Justyna
Gomon, S. Svyatoslav
Polishchuk, Mykola
Homon, Sviatoslav
Gomon, Petro
Karavan, Victor
Organization
UTP University of Science and Technology
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Reinforcement
Bending Behaviour
Research Status
Complete
Series
Buildings
Summary
Wood is one of the most popular renewable natural materials. Nowadays, raw wood is hardly ever used in the construction industry. It has been substituted by glued laminated wood that is processed with the use of high-tech methods, thus eliminating the principal flaws and defects of the natural material. The deformability of glued laminated beams with combined reinforcement has been studied, under which the steel reinforcement of the periodic profile was placed in the dappings of the upper compressed zone, while ribbon-reinforced composite was glued to the bottom of the stretched zone. The graphical charts for the layer change of the deformations of wood, steel, and composite reinforcement from the beginning of the loading application to the moment of destruction are presented.
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The Design of Cross-Laminated Timber Slabs with Cut-Back Glulam Rib Downstands - From Research to Live Project

https://research.thinkwood.com/en/permalink/catalogue1736
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Author
Papastavrou, Panayiotis
Smith, Simon
Wallwork, Tristan
McRobie, Allan
Niem, Nicholas
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Finite Element Modelling
Full-Scale
Embedment Depth
Reinforcement
Screws
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4809-4818
Summary
A research project was undertaken to investigate the behaviour of composite CLT slabs with glulam downstands cut back from the supports. A desk study and Finite Element Modelling (FEM) were used and evaluated on their ability to model and design such a structure, focusing on the cut back location and utilising reinforcement screws. The project included full-scale laboratory testing of a composite slab to failure with innovative data collection techniques such as Particle Image Velocimetry. A similar structural element was also used in a real construction project and the investigation gave insight towards its design. It was concluded that the embedment depth of reinforcement screws in the glulam downstand is key to the performance of the composite slab with full depth penetration advisable. FEM can give useful results for stress concentrations in the timber and a simplified design method was proposed.
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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
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Design and Systems
Keywords
Shear
Reinforcement
Fractured
Unfractured
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. 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, 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. With respect to their application as shear reinforcement, not many research results are yet available, 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. 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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50 records – page 1 of 5.