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424 records – page 1 of 43.

Experimental Behavior of a Continuous Metal Connector for a Wood-Concrete Composite System

https://research.thinkwood.com/en/permalink/catalogue730
Year of Publication
2004
Topic
Connections
Design and Systems
Mechanical Properties
Material
Timber-Concrete Composite
PSL (Parallel Strand Lumber)
Application
Floors
Author
Clouston, Peggi
Civjan, Scott
Bathon, Leander
Publisher
Forest Products Society
Year of Publication
2004
Format
Journal Article
Material
Timber-Concrete Composite
PSL (Parallel Strand Lumber)
Application
Floors
Topic
Connections
Design and Systems
Mechanical Properties
Keywords
Pine
US
Continuous Steel Mesh
Steel Connectors
Push-Out Tests
Shear Strength
Stiffness
Bending Tests
Research Status
Complete
Series
Forest Products Journal
Summary
The benefits of using shear connectors to join wood beams to a concrete slab in a composite floor or deck system are many. Studies throughout the world have demonstrated significantly improved strength, stiffness, and ductility properties from such connection systems as well as citing practical building advantages such as durability, sound insulation, and fire resistance. In this study, one relatively new shear connector system that originated in Germany has been experimentally investigated for use with U.S. manufactured products. The connector system consists of a continuous steel mesh of which one half is glued into a southern pine Parallam® Parallel Strand Lumber beam and the other half embedded into a concrete slab to provide minimal interlayer slip. A variety of commercial epoxies were tested for shear strength and stiffness in standard shear or “push out” tests. The various epoxies resulted in a variety of shear constitutive behaviors; however, for two glue types,shear failure occurred in the steel connector resulting in relatively high initial stiffness and ductility as well as good repeatability. Slip moduli and ultimate strength values are presented and discussed. Full-scale bending tests, using the best performing adhesive as determined from the shear tests, were also conducted. Results indicate consistent, near-full composite action system behavior.
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Timber Rivets in Structural Composite Lumber

https://research.thinkwood.com/en/permalink/catalogue777
Year of Publication
2004
Topic
Connections
Material
LSL (Laminated Strand Lumber)
PSL (Parallel Strand Lumber)
Author
Wolfe, Ronald
Begel, Marshall
Craig, Bruce
Organization
Forest Products Laboratory
Year of Publication
2004
Format
Report
Material
LSL (Laminated Strand Lumber)
PSL (Parallel Strand Lumber)
Topic
Connections
Keywords
Pine
Poplar
Rivets
Failure
Research Status
Complete
Summary
Timber rivet connections, originally developed for use with glulam construction, may be a viable option for use with structural composite lumber (SCL) products. Tests were conducted on small samples to assess the performance and predictability of timber rivet connections in parallel strand lumber (PSL) and laminated strand lumber (LSL). The test joint configurations were designed to exhibit ìrivet failuresîósome combination of rivet yield and bearing deformation in the compositeóas opposed to wood failure modes, such as block-shear tear-out or splitting. Results suggest that per-rivet design values should fall between 1 and 2 kN, depending on species and density of the composite and load direction with respect to grain of the composite strands. Timber rivets performed better in LSL than in PSL and better in yellow poplar PSL than in Douglas-fir or Southern Pine PSL; 40-mm rivets in yellow poplar LSL gave roughly equivalent performance to 65-mm rivets in yellow poplar PSL.
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Structural Safety and Rehabilitation of Connections in Wide-Span Timber Structures - Two Exemplary Truss Systems

https://research.thinkwood.com/en/permalink/catalogue1485
Year of Publication
2008
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Bridges and Spans
Author
Dietsch, Philipp
Merk, Michael
Mestek, Peter
Winter, Stefan
Organization
Technical University of Munich
Year of Publication
2008
Format
Report
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Bridges and Spans
Topic
Connections
Mechanical Properties
Keywords
Failure Mechanisms
Wide-Span
Cracks
Glue Lines
Strength
Research Status
Complete
Summary
Following the Bad Reichenhall ice-arena collapse, numerous expertises on the structural safety of wide-span timber structures were carried out at the Chair of Timber Structures and Building Construction. It became evident that inadequate structural design and detailing as well as inadequate manufacturing principles were the main reasons for observed failures. The design and manufacture of connections in wide-span timber structures are still amongst the most challenging tasks for both the structural engineer as well as the executing company. This paper will, on the basis of two exemplary expertises, discuss specific issues in the structural reliability of connections in wide-span timber trusses and give recommendations towards a state-of-the art design of such connections.
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Lateral Load Resistance of Cross-Laminated Wood Panels

https://research.thinkwood.com/en/permalink/catalogue2150
Year of Publication
2010
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Popovski, Marjan
Schneider, Johannes
Schweinsteiger, Matthias
Year of Publication
2010
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Connections
Seismic
Keywords
Quasi-Static Tests
Seismic Performance
Screws
Nails
Steel Brackets
Timber Rivets
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
In this paper, some of the results are presented from a series of quasi-static tests on CLT wall panels conducted at FPInnovation-Forintek in Vancouver, BC. CLT wall panels with various configurations and connection details were tested. Wall configurations included single panel walls with three different aspect ratios, multi-panel walls with step joints and different types of screws to connect them, as well as two-storey wall assemblies. Connections for securing the walls to the foundation included: off-the-shelf steel brackets with annular ring nails, spiral nails, and screws; combination of steel brackets and hold-downs; diagonally placed long screws; and custom made brackets with timber rivets. Results showed that CLT walls can have adequate seismic performance when nails or screws are used with the steel brackets. Use of hold-downs with nails on each end of the wall improves its seismic performance. Use of diagonally placed long screws to connect the CLT walls to the floor below is not recommended in high seismic zones due to less ductile wall behaviour. Use of step joints in longer walls can be an effective solution not only to reduce the wall stiffness and thus reduce the seismic input load, but also to improve the wall deformation capabilities. Timber rivets in smaller groups with custom made brackets were found to be effective connectors for CLT wall panels. Further research in this field is needed to further clarify the use of timber rivets in CLT.
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Technical Note: Effects of Nanoclay Addition to Phenol-Formaldehyde Resin on the Permeability of Oriented Strand Lumber

https://research.thinkwood.com/en/permalink/catalogue1465
Year of Publication
2010
Topic
Connections
Material
OSL (Oriented Strand Lumber)
Author
Zhang, Chao
Smith, Gregory
Publisher
Society of Wood Science and Technology
Year of Publication
2010
Format
Journal Article
Material
OSL (Oriented Strand Lumber)
Topic
Connections
Keywords
Phenol Formaldehyde
Adhesives
Permeability
Nanoclays
Lodgepole Pine
Mountain Pine Beetle
Research Status
Complete
Series
Wood and Fiber Science
Summary
This note examined the effects of adding nanoclays to phenol-formaldehyde resin during the manufacture of oriented strand lumber (OSL) on its in-plane permeability. The panels were made from mountain pine beetle (MPB) attacked lodgepole pine (Pinus contorta) strands. Three different montmorillonite nanoclays were mixed with the PF resin: Na+, hydrophobic organics modified 10A, and hydrophilic organics modified 30B. None of the nanoclays changed the permeability of OSL significantly. The MPB-OSL had higher in-plane permeability than those conventionally made from aspen, which indicated that the pressing time could be shorter for MPB-OSL compared with OSL made from MPB-free strands.
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Tensile Performance of Machine-Cut Dovetail Joint with Larch Glulam

https://research.thinkwood.com/en/permalink/catalogue1509
Year of Publication
2010
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Park, Joo-Saeng
Hwang, Kweon-Hwan
Park, Moon-Jae
Shim, Kug-Bo
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2010
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Larch
Dovetail Joints
Tensile Strength
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
Members used for the Korean traditional joints have been processed by handicraft, especially with domestic red pine species. Dovetail joint is most commonly used in woodworking joinery and traditional horizontal and vertical connections. It is able to be processed much easier to cut by handicraft and machines. However, although it is processed straight forwards, it requires a high degree of accuracy to ensure a snug fit. Also, tenons and mortises must fit together with no gap between them so that the joint interlocks tightly. A few scientific studies on the dovetail joints have been conducted so far. For the effective applications of traditional joints and domestic plantation wood species, dovetail joints were assembled by larch glulam members processed by machine pre-cut. To identify the tensile properties of through dovetail joints, larch glulam with 150 150mm in cross section were prepared. Furthermore, various geometric parameters of dovetai joints such as width, length, and tenon angle, were surveyed. The ends in the mortise was cracked mainly at a low strength level in the control specimens without reinforcements. The maximum tensile strengths of reinforced specimens considering real connections such as capital joint and headpiece on a column, increasedby handicraft, especially with domestic red pine species. Dovetail joint is most commonly used in woodworking joinery and traditional horizontal and vertical connections. It is able to be processed much easier to cut by handicraft and machines. However, although it is processed straight forwards, it requires a high degree of accuracy to ensure a snug fit. Also, tenons and mortises must fit together with no gap between them so that the joint interlocks tightly. A few scientific studies on the dovetail joints have been conducted so far. For the effective applications of traditional joints and domestic plantation wood species, dovetail joints were assembled by larch glulam members processed by machine pre-cut. To identify the tensile properties of through dovetail joints, larch glulam with 150 150mm in cross section were prepared. Furthermore, various geometric parameters of dovetai joints such as width, length, and tenon angle, were surveyed. The ends in the mortise was cracked mainly at a low strength level in the control specimens without reinforcements. The maximum tensile strengths of reinforced specimens considering real connections such as capital joint and headpiece on a column, increased by two times with shear failures on the tenon than the control specimens. The maximum tensile strength was obtained in the specimen of 25 degrees, and no difference was observed in the changes of neck widths.
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Accommodating Movement in High-Rise Wood-Frame Building Construction

https://research.thinkwood.com/en/permalink/catalogue1875
Year of Publication
2011
Topic
Design and Systems
Connections
Material
Steel-Timber Composite
Other Materials
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Floors
Walls
Author
Howe, Richard
Publisher
Forest Products Society
Year of Publication
2011
Format
Journal Article
Material
Steel-Timber Composite
Other Materials
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Floors
Walls
Topic
Design and Systems
Connections
Keywords
Detailing
Shrinkage
Differential Movement
Research Status
Complete
Series
Wood Design Focus
Summary
Ease of construction and favorable overall costs relative to other construction types are making high-rise (i.e., 4- and 5-story) wood frame construction increasingly popular. With these buildings increasing in height, there is a greater impetus on designers to address frame and finishes movement in such construction. As we all know, buildings are dynamic creatures experiencing a variety of movements during construction and over their service life. In wood frame construction, it is important to consider not only absolute movement but also differential movement between dissimilar materials. This article focuses on differential movement issues and how to recognize their potential and avoid problems by effective detailing.
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Bond Behavior between Glulam and GFRP’s by Pullout Tests

https://research.thinkwood.com/en/permalink/catalogue560
Year of Publication
2011
Topic
Connections
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Author
Sena-Cruz, José
Branco, Jorge
Jorge, Marco
Barros, Joaquim
Silva, Catarina
Cunha, Vitor
Publisher
ScienceDirect
Year of Publication
2011
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Design and Systems
Keywords
GFRP
Bond behavior
Pull-Out Tests
Stress-Slip
Research Status
Complete
Series
Composites Part B: Engineering
Summary
To evaluate the bond behavior between glulam and GFRP rods, applied according to the nearsurface mounted strengthening technique, an experimental program composed of beam and direct pullout tests was carried. In this experimental program three main variables were analyzed: the GFRP type, the GFRP location into the groove, and the bond length. From the monitoring system it was registered the loaded and free end slips, and the pullout force. Based on these experimental results, and applying an analytical-numerical strategy, the local bond stress-slip relationship was calculated. In this work the tests are described, the obtained results are presented and discussed, and the applicability of the inverse analysis to obtain the local bond law is demonstrated.
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Wind-Induced Vibration of Tall Wood Buildings

https://research.thinkwood.com/en/permalink/catalogue1105
Year of Publication
2011
Topic
Wind
Connections
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Reynolds, Thomas
Chang, Wen-Shao
Harris, Richard
Organization
TRADA
Year of Publication
2011
Format
Report
Material
Glulam (Glue-Laminated Timber)
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Wind
Connections
Keywords
Across-Wind Vibration
Turbulence
Along-Wind Vibration
Vortex Shedding
Research Status
Complete
Summary
Wind-induced vibration is an important design consideration in tall buildings in any structural material. The two main forms of wind-induced vibration - across-wind vibration due to vortex shedding and along-wind vibration due to turbulence - were taken into consideration when undertaking this study. Both types are addressed in Eurocode 1. This research summary discusses a study which, following a sensitivity study into the effect of stiffness and damping on wind-induced vibration, addresses a shortfall in current knowledge of stiffness in dowel-type connections. This type of connection is found in the glulam frame and CLT structures currently at the forefront of tall timber construction, and its behaviour was investigated by measuring and analysing stiffness and damping under oscillating loads representative of wind-induced vibration. This research summary covers a number of factors relating to wind-induced vibration which must be considered when constructing a tall timber building, such as how to assess connection stiffness under in-service vibration. The various conditions were then applied to a case study - the proposed Barentshaus building.
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Analytical Model to Evaluate the Equivalent Viscous Damping of Timber Structures with Dowel-Type Fastener Connections

https://research.thinkwood.com/en/permalink/catalogue1893
Year of Publication
2012
Topic
Connections
Application
Frames
Author
Loss, Cristiano
Piazza, Maurizio
Zonta, Daniele
Year of Publication
2012
Format
Conference Paper
Application
Frames
Topic
Connections
Keywords
Equivalent Viscous Damping
Moment Resisting Joints
Dowel-Type Connections
Non-linear Dynamic Analysis
Metal Fasteners
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
July 16-19, 2012, Auckland, New Zealand
Summary
The Equivalent Viscous Damping (EVD) parameter is used to simplify the dynamic problem, passing from a non-linear solution of the system to a simple linear-elastic one. In the case of Direct Displacement-Based seismic Design (DDBD) methods, the EVD value allows direct design of structures, without an iterative computational process. This paper proposes a rational analytical formula to evaluate the EVD value of timber structures with dowel-type metal fastener connections. The EVD model is developed at the ultimate limit state, as a solution of the equilibrium problem related to an inelastic configuration. For a specific joint configuration, the EVD predicted via an analytical model was compared to experimental results. The proposed EVD model was validated using non-linear dynamic analysis on a portal frame, built with dowel-type fasteners arranged in two concentric crowns.
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424 records – page 1 of 43.