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7 records – page 1 of 1.

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.
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Investigations on the Serviceability Limit State of Dowel-Type Timber Connections

https://research.thinkwood.com/en/permalink/catalogue911
Year of Publication
2012
Topic
Serviceability
Connections
Author
Dorn, Micheal
Organization
Vienna University of Technology
Year of Publication
2012
Format
Thesis
Topic
Serviceability
Connections
Keywords
dowel-type connection
Steel-to-Timber
Failure Modes
Ductility
Eurocode 5
Strength
Stiffness
contact behavior
finite element method
Research Status
Complete
Summary
The aim of this thesis is to study the load-carrying behaviour of dowel-type steel-to-timber connections in detail. This is achieved by performing experimental tests on single-dowel connections. A large variety of influencing parameters is assessed, which include wood density, connection width, the dowel roughness, and the application of reinforcements in order to prevent brittle behaviour. Separate stages in the loading history are identified, starting from an initial consolidation phase, the region of maximum stiffness during load increase, and the point of maximum connection strength. The results of the experiments are compared to the design practice in Eurocode 5 for strength and stiffness estimation. Strength prediction is conservative except for slender connections, while stiffness prediction complied with experimental results only for connections of intermediate width.
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Numerical Modelling of Steel-to-Timber Joints and Connectors for CLT Structures

https://research.thinkwood.com/en/permalink/catalogue1604
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Izzi, Matteo
Rinaldin, Giovanni
Fragiacomo, Massimo
Polastri, Andrea
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Strength
Shear Tests
Steel-to-Timber
Joints
Nails
Hysteretic Model
Stochastic Approach
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 2032-2040
Summary
The mechanical behaviour of steel-to-timber joints with annular-ringed shank nails is investigated using numerical modelling and a component approach. These joints are used in Cross-Laminated Timber (CLT) buildings to anchor metal connectors such as hold-downs and angle brackets to the timber panels. At first, a general hysteresis model is introduced, where a single fastener joint is schematized as an elasto-plastic beam embedded in a non-linear medium with a compression-only behaviour. A second hysteresis model is then presented, where the mechanical behaviour of the joint is simulated by a non-linear spring with three degrees of freedom. Both models are calibrated on the design rules prescribed by the reference standards. Moreover, average strength capacities are determined from the corresponding characteristic values assuming a standard normal distribution and suitable coefficients of variation. As first applicative examples of the proposed models, shear tests are simulated on single steel-to-timber joints with annular-ringed shank nails and on a connection made of an angle bracket and sixty nails. The scatter of mechanical properties in steel-to-timber joints is also taken into account in the simulations and a stochastic approach is proposed, demonstrating acceptable accuracy.
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Performance of Timber Connections Exposed to Fire: A Review

https://research.thinkwood.com/en/permalink/catalogue233
Year of Publication
2015
Topic
Connections
Fire
Material
LVL (Laminated Veneer Lumber)
Author
Maraveas, Chrysanthos
Miamis, K.
E. Matthaiou, Ch.
Publisher
Springer US
Year of Publication
2015
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Fire
Keywords
Temperature
Steel-to-Timber
Wood-to-Wood
Research Status
Complete
Series
Fire Technology
Summary
Fire safety has always been a major concern in the design of timber construction. Even though wood is a highly combustible material, timber members can perform adequately under elevated temperatures. The thermal response of timber connections, however, is in most cases poor and determination of their fire resistance is usually the crucial factor in evaluating the overall load-bearing capacity of wood structures exposed to fire. The analysis of timber joints under fire conditions can be challenging due to their complexity and variety. After presenting the variation of the properties of timber with temperature, this paper reviews the fire performance of various connection types, such as bolted or nailed wood-to-wood and steel-to-timber joints. Results from relevant experimental programs and numerical studies are discussed in detail and future research needs are highlighted. The effect of several factors on the fire resistance of timber connections, such as the fastener diameter, timber thickness and joint geometry, is investigated and useful conclusions are drawn. Based on these, preliminary guidelines for the efficient design of timber connections under fire exposure are presented.
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Steel-to-Timber Joints of Beech-LVL with Very High Strength Steel Dowels

https://research.thinkwood.com/en/permalink/catalogue1502
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Misconel, Andrea
Ballerini, Marco
Van de Kuilen, Jan-Willem
Year of Publication
2016
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Beech
Steel-to-Timber
Joints
Steel Plates
Steel Dowels
Very High Strength Steel
Tensile Tests
Full Scale
Load Carrying Capacity
Ductility
Stiffness
Eurocode 5
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 301-308
Summary
Double-shear steel-to-timber joints of beech laminated veneer lumber (LVL) with slotted-in steel plates using very high strength steel (VHSS) dowels have been investigated. Tensile tests on full-scale joints with one, two, three and six dowels have been carried out, using both VHSS and mild steel dowels. The goal of the research was to investigate the mechanical behaviour of joints of beech-LVL, with regard to load-carrying capacity (LCC), ductility, stiffness; and to find out whether the current design rules of Eurocode 5 are suitable for LVL and VHSS steels. Other examined aspects were the effect of multiple fasteners in a row and the influence of fastener steel grade. Tests showed higher values of joints with VHSS dowels, characterized generally by low scatter. The prediction ability of Eurocode 5 has been found to be inadequate and too conservative. A proposal for improvement is included.
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Stiffness of Dowelled Steel-to-Timber Joints

https://research.thinkwood.com/en/permalink/catalogue1497
Year of Publication
2016
Topic
Mechanical Properties
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Xu, Bo-Han
Yuan, Dong-Wei
Bouchaïr, Abdelhamid
Racher, Patrick
Year of Publication
2016
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Connections
Keywords
Stiffness
Dowels
Steel-to-Timber
Joints
Tensile Load
Codes
National Design Specifications for Wood Construction (NDSR)
Eurocode
Grain Orientation
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 219-226
Summary
The mechanical behaviour of timber structures is significantly influenced by the stiffness, load-carrying capacity and ductility of the joints. This study is focused on the stiffness of dowelled steel-to-timber joints, which were subjected to tensile loadings at different orientations with regard to the grain direction (0°, 30°, 45°, 60° and 90°). The values of the joint stiffness in service obtained from the tests were compared with predictive values from current design codes (Eurocode 5 and NDS). The current design codes showed their weak predictive ability. Besides timber density and fastener diameter, as well as clearance and friction between the joint members, orientation of load with respect to timber grain and dowel slenderness ratio are also the important factors that affect the stiffness of a joint. An empirical expression of stiffness for steel-to-timber joints with single dowel was proposed on the basis of the formula in Eurocode 5 and the Hankinson-type formula using non-linear fitting of the experiment results.
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7 records – page 1 of 1.