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Dowel Deformations in Multi-Dowel LVL-Connections Under Moment Loading

https://research.thinkwood.com/en/permalink/catalogue583
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Bader, Thomas
Schweigler, Michael
Hochreiner, Georg
Serrano, Erik
Enquist, Bertil
Dorn, Michael
Publisher
Taylor&Francis Online
Year of Publication
2015
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Ductility
Bending Moment
Steel Dowels
Double-Shear
Steel-to-Timber
Four Point Bending Test
Research Status
Complete
Series
Wood Material Science & Engineering
Summary
The aim of the experimental study presented herein is the assessment and quantification of the behavior of individual dowels in multi-dowel connections loaded by a bending moment. For this purpose, doubleshear, steel-to-timber connections with nine steel dowels arranged in different patterns and with different dowel diameters were tested in 4-point bending. In order to achieve a ductile behavior with up to 7° relative rotation, the connections were partly reinforced with self-tapping screws. The reinforcement did not influence the global load-deformation behavior, neither for dowel diameters of 12 mm nor for 20 mm, as long as cracking was not decisive. The deformation of the individual dowels was studied by means of a non-contact deformation measurement system. Thus, the crushing deformation, i.e. the deformation at the steel plate, and the bending deformation of the dowels could be quantified. In case of 12 mm dowels, the bending deformation was larger than the crushing deformation, while it was smaller in case of 20 mm dowels. Moreover, dowels loaded parallel to the grain showed larger bending deformations than dowels loaded perpendicular to the grain. This indicates that the loading of the individual dowels in the connection differs, depending on their location.
Online Access
Free
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Effect of Holes on the Structural Capacities of Laminated Veneer Lumber

https://research.thinkwood.com/en/permalink/catalogue2045
Year of Publication
2018
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Yeh, Borjen
Herzog, Benjamin
Year of Publication
2018
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Holes
Bending Moment
Shear
Bending Stiffness
Bending Tests
Shear Tests
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
Laminated veneer lumber (LVL) is an engineered wood product manufactured from specially selected veneers with varying strength and stiffness properties. LVL products are often specified where a certain span, strength and/or stiffness is required. As such, LVL products are generally designed for and used in applications where they will be highly stressed under design loads. For this reason, field modifications, such as notching, tapering, or drilling should be avoided and never done without a thorough understanding of the effects on the structural capacities of the LVL. Nonetheless, it is not uncommon for the designer and contractor to find a need to cut holes through LVL members for plumbing pipes, electrical conduits, or air ducts. Therefore, it is usually necessary to determine the residual structural capacities of the LVL member when holes are cut. The objective of this paper is to examine the effect of round holes on the structural capacities of LVL, including bending moment, shear, and bending stiffness. Full-scale LVL bending and shear tests were conducted to provide data for characterization of the hole effect. Based on the test data, design equations that account for single and multiple holes up to 2/3 of the LVL member depth and a clear distance of 15% or more of the LVL depth from the edge of the hole to either tension and compression edge of the LVL member have been developed. To ensure safe implementation of such design recommendations in practice, prescriptive limitations, such as the minimum clear distance between the face of a support and the edge of a hole, and the minimum clear distance between adjacent holes, are also prescribed.
Online Access
Free
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A Novel Method for Non-linear Design of CLT Wall Systems

https://research.thinkwood.com/en/permalink/catalogue1196
Year of Publication
2018
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Tamagnone, Gabriele
Rinaldin, Giovanni
Fragiacomo, Massimo
Publisher
ScienceDirect
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Mechanical Properties
Connections
Keywords
Metal Connections
Failure Mechanism
Bending Moment
Axial Force
Rocking Capacity
Research Status
Complete
Series
Engineering Structures
Summary
In this paper, a non-linear procedure for the seismic design of metal connections in cross-laminated timber (CLT) walls subjected to bending and axial force is presented. Timber is conservatively modelled as an elasto-brittle material, whereas metal connections (hold-downs and angle brackets) are modelled with an elasto-plastic behavior. The reaction force in each connection is iteratively calculated by varying the position of the neutral axis at the base of the wall using a simple algorithm that was implemented first in a purposely developed spreadsheet, and then into a purposely developed software. This method is based on the evaluation of five different failure mechanisms at ultimate limit state, starting from the fully tensioned wall to the fully compressed one, similarly to reinforced concrete (RC) section design. By setting the mechanical properties of timber and metal connections and the geometry of the CLT panel, the algorithm calculates, for every axial load value, the ultimate resisting moment of the entire wall and the position of the neutral axis. The procedure mainly applies to platform-type structures with holddowns and angle brackets connections at the base of the wall and rocking mechanism as the prevalent way of dissipation. This method allows the designer to have information on the rocking capacity of the system and on the failure mechanism for a given distribution of external loads. The proposed method was validated on the results of FE analyses using SAP2000 and ABAQUS showing acceptable accuracy.
Online Access
Free
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Salvaged Lumber for Structural Mass Timber Panels: Manufacturing and Testing

https://research.thinkwood.com/en/permalink/catalogue2470
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)

A Simplified Non-Linear Procedure for Seismic Design of CLT Wall Systems

https://research.thinkwood.com/en/permalink/catalogue1685
Year of Publication
2016
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Tamagnone, Gabriele
Rinaldin, Giovanni
Fragiacomo, Massimo
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Design and Systems
Seismic
Keywords
Axial Force
Bending Moment
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4191-4200
Summary
In this paper, a simplified non-linear procedure for seismic design of CLT (cross-laminated timber) wall systems is presented. The proposed method considers both axial force and bending moment applied on the wall systems as result of applied loads. Timber is modelled as an elastic-brittle material, whereas metal connections (hold-downs and angle brackets) are modelled with an elastic-plastic behaviour. The reaction force in each connection is iteratively calculated by varying the position of the neutral axis at the base of the wall using a simple algorithm that has been implemented in a purposely-developed software. This method is based on the evaluation of five different failure mechanisms at ultimate limit state similarly to reinforced concrete (RC) rectangular section design. By setting the mechanical properties of timber and metal connections, and the geometry of the CLT panel, the algorithm calculates, for every possible axial load, the position of the neutral axis and the ultimate resisting moment of the system. Furthermore, this method also allows the designer to have an indication on the failure mechanism of the wall.
Online Access
Free
Resource Link
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