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26 records – page 1 of 3.

Accurate Strength Parameters for Fasteners with Examples for Ring Shank Nails

https://research.thinkwood.com/en/permalink/catalogue1510
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Munch-Andersen, Jørgen
Svensson, Staffan
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Withdrawal Test
Ring Shank Nails
Fasteners
Strength
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 344-352
Summary
Strength parameters for fasteners determined in accordance with the methods prescribed for the European CE-marking leads to quite different values for seemingly similar products from different manufactures. The results are hardly repeatable, to some extent due to difficulties in selecting representative on engineered wood products...
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An Equivalent Truss Method for the Analysis of Timber Diaphragms

https://research.thinkwood.com/en/permalink/catalogue112
Year of Publication
2015
Topic
Design and Systems
Mechanical Properties
Material
Light Frame (Lumber+Panels)
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Moroder, Daniel
Smith, Tobias
Pampanin, Stefano
Buchanan, Andrew
Year of Publication
2015
Country of Publication
Australia
Format
Conference Paper
Material
Light Frame (Lumber+Panels)
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Design and Systems
Mechanical Properties
Keywords
Diaphragms
Equivalent Truss Method
Fasteners
Forces
Deflection
Torsion
Language
English
Conference
Pacific Conference on Earthquake Engineering
Research Status
Complete
Notes
November 6-8, 2015, Sydney, Australia
Summary
Recent years have seen more architects and clients asking for tall timber buildings. In response, an ambitious timber community has been proposing challenging plans and ideas for multi-storey commercial and residential timber buildings. While engineers have been intensively looking at gravity-load-carrying elements as well as walls, frames and cores to resist lateral loads, floor diaphragms have been largely neglected. Complex floor geometries and long span floor diaphragms create stress concentrations, high force demand and potentially large deformations. There is a lack of guidance and regulation regarding the analysis and design of timber diaphragms so structural engineers need a practical alternative to simplistic equivalent deep beam analysis or costly finite element modelling. This paper proposes an equivalent truss method capable of solving complex geometries for both light timber framing and massive timber diaphragms. Floor panels are discretized by equivalent diagonals, having the same stiffness as the panel including its fasteners. With this method the panel unit shear forces (shear flow) and therefore fastener demand, chord forces and reaction forces can be evaluated. Because panel stiffness is accounted for, diaphragm deflection, torsional effects and transfer forces can also be assessed.
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Connection Wood Brittle Failure in Cross-Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue1552
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Zarnani, Pouyan
Quenneville, Pierre
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Fasteners
Brittle Failure
Failure Modes
Stiffness-Based Design Approach
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1233-1240
Summary
The introduction of Cross-laminated Timber (CLT) as an engineered timber product has played a significant role in the 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...
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Conventional and Novel Timber Steel Hybrid Connections: Testing, Performance and Assessment

https://research.thinkwood.com/en/permalink/catalogue187
Year of Publication
2015
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Schneider, Johannes
Organization
University of British Columbia
Year of Publication
2015
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Seismic
Keywords
Timber-Steel Hybrid
Fasteners
Quasi-Static
Monotonic Loading
Cyclic Loading
Brackets
Tube Connections
Language
English
Research Status
Complete
Summary
The focus of this research is the connection between steel frame and the infill wall. Over 100 conventional bracket-type connections with various combinations of bracket and fasteners with cross-laminated timber were tested, investigated and assessed for damage under seismic loading protocols for a hybrid application. An energy-based formulation according to Krätzig was applied to calculate the development of the damage index, and the resulting index was validated with visual observation. Six of the connections were modeled in OpenSees. For the modeling, a CUREE-10 parameter model was chosen to reproduce the test curves. The load-displacement results from both test and model were analyzed; the first method according to ASTM standards, where the envelope curve of the hysteretic results are considered and plotted in an equivalent energy elastic-plastic curve (EEEP). The second analyzing method used, was Krätzig’s damage accumulation model. Throughout all six combinations and both loading directions (parallel- and perpendicular-to-the-grain) a major difference was found in the analyzing methods. The EEEP curve roughly approximates the performance but with the damage accumulation method showed that analysis of the subsequent cycles is required to better reflect the empirical performance of the connections. To avoid the extensive destruction of a bracket type connection after completion of seismic loadings, a new approach was chosen. It was found that a tube connection can obtain comparably similar strength results as a conventional bracket connection. The computed mechanical properties of bracket-type and tube-type connections were compared and evaluated. The new tube connection showed great potential for future timber-steel hybrid structures and their connecting challenge. A total of 27 connection assemblies were tested under quasi-static monotonic and reversed cyclic loads. The tube connections showed two major differences when compared to traditional bracket connections: i) the completely linear elastic behaviour at the beginning, and ii) the continued load increase after yielding. Both phenomena are founded in the geometry of that connector effectively making the novel connector a very promising alternative.
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Cyclic Performance of Connections used in Hybrid Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1367
Year of Publication
2017
Topic
Connections
Design and Systems
Material
CLT (Cross-Laminated Timber)

Damage Assessment of Connections used in Cross-Laminated Timber Subject to Cyclic Loads

https://research.thinkwood.com/en/permalink/catalogue225
Year of Publication
2014
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Schneider, Johannes
Karacabeyli, Erol
Popovski, Marjan
Stiemer, Siegfried
Tesfamariam, Solomon
Publisher
American Society of Civil Engineers
Year of Publication
2014
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Seismic
Keywords
Fasteners
Damage Index (DI) Method
Brackets
Load Displacement
Hysteretic
Language
English
Research Status
Complete
Series
Journal of Performance of Constructed Facilities
Notes
https://doi.org/10.1061/(ASCE)CF.1943-5509.0000528
Summary
Cross-laminated timber (CLT) products are gaining popularity in the North American market and are being used in midrise wood buildings, in particular, in shearwall applications. Shearwalls provide resistance to lateral loads such as wind and earthquake loads, and therefore it is important to gain a better understanding of the behavior of CLT shearwall systems during earthquake events. This paper is focused on the seismic performance of connections between CLT shearwall panels and the foundation. CLT panels are very stiff and energy dissipation is accomplished by the connections. A literature review on previous research work related to damage prediction and assessment for wood frame structures was performed. Furthermore, a test program was conducted to investigate the performance of CLT connections subjected to simulated earthquake loads. Two different brackets in combination with five types of fasteners were tested under monotonic and cyclic loading protocols. In total, 98 connection tests were conducted and the monotonic load-displacement curves and hysteretic loops were obtained. In this paper, an energy-based cumulative damage assessment model was calibrated with the CLT connection test data. Finally, a correlation between the damage index and physical damage is provided.
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Development and Evaluation of Mechanical Joints for Composite Floor Elements with Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue208
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Author
Jacquier, Nicolas
Organization
Luleå University of Technology
Year of Publication
2015
Country of Publication
Sweden
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Topic
Connections
Mechanical Properties
Keywords
Fasteners
Metal Plate
Strength
Stiffness
Double-sided Nail Plates
Language
English
Research Status
Complete
Summary
This thesis focuses on the development of composite floor solutions where Cross Laminated Timber (CLT) panels are used as a base element. Preliminary investigations on shear connections between prefabricated concrete beams and CLT panels were performed. The focus is on investigations on glulam-CLT composite beam elements, and the mechanical shear connectors used to achieve composite action. The new shear connections system evaluated in this thesis for glulam-CLT floor elements consists of double-sided punched metal plate fasteners. In order to secure the shear connection made with double-sided nail plates and to improve the shear behaviour of the joint, a combination with inclined self-tapping screws was evaluated through a shear test programme. It was found that the double-sided punched metal plate fasteners and inclined screws can effectively be combined.
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Development of Mass Timber Wall System Based on Nail Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2526
Year of Publication
2020
Topic
Design and Systems
Material
NLT (Nail-Laminated Timber)
Application
Walls
Author
Zhang, Chao
Lee, George
Lam, Frank
Organization
Timber Engineering and Applied Mechanics (TEAM) Laboratory
Year of Publication
2020
Country of Publication
Canada
Format
Report
Material
NLT (Nail-Laminated Timber)
Application
Walls
Topic
Design and Systems
Keywords
Shear
Stiffness
Fasteners
Fastener Type
Load
Language
English
Research Status
Complete
Summary
This project studied the feasibility and performance of a mass timber wall system based on Nail Laminated Timber (NLT) for floor/wall applications, in order to quantify the effects of various design parameters. Thirteen 2.4 m × 2.4 m shear walls were manufactured and tested in this phase. Together with another five specimens tested before, a total eighteen shear wall specimens and ten configurations were investigated. The design variables included fastener type, sheathing thickness, number of sheathings, sheathing material, nailing pattern, wall opening, and lumber orientation. The NLT walls were made of SprucePine-Fir (SPF) No. 2 2×4 (38 mm × 89 mm) lumber and Oriented Strand Lumber (OSB) or plywood sheathing. They were tested under monotonic and reverse-cyclic loading protocols, in accordance with ASTM E564-06 (2018) and ASTM E2126-19, respectively. Compared to traditional wood stud walls, the best performing NLT based shear wall had 2.5 times the peak load and 2 times the stiffness at 0.5-1.5% drift, while retaining high ductility. The advantage of these NLT-based wall was even greater under reverse-cyclic loading due to the internal energy dissipation of NLT. The wall with ring nails had higher stiffness than the one with smooth nails. But the performance of ring nails deteriorated drastically under reverse-cyclic loading, leading to a considerably lower capacity. Changing the sheathing thickness from 11 mm to 15 mm improved the strength by 6% while having the same initial stiffness. Adding one more face of sheathing increased the peak load and stiffness by at least 50%. The wall was also very ductile as the load dropped less than 10% when the lateral displacement exceeded 150 mm. The difference created by sheathing material was not significant if they were of the same thickness. Reducing the nailing spacing by half led to a 40% increasing in the peak load and stiffness. Having an opening of 25% of the area at the center, the lateral capacity and stiffness reached 75% or more of the full wall. A simplified method to estimate the lateral resistance of this mass timber wall system was proposed. The estimate was close to the tested capacity and was on the conservative side. Recommendations for design and manufacturing the system were also presented.
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Ductility Based Force Reduction Factors for Symmetrical Cross-Laminated Timber Structures

https://research.thinkwood.com/en/permalink/catalogue446
Year of Publication
2014
Topic
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Author
Popovski, Marjan
Pei, Shiling
van de Lindt, John
Karacabeyli, Erol
Organization
European Association of Earthquake Engineering
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Topic
Mechanical Properties
Seismic
Keywords
Force Modification Factors
Ductility
National Building Code of Canada
Fasteners
Seismic Performance
Language
English
Conference
Second European Conference on Earthquake Engineering and Seismology
Research Status
Complete
Notes
August 25-29, 2014, Istanbul, Turkey
Summary
Cross-laminated timber (CLT) as a structural system has not been fully introduced in European or North American building codes. One of the most important issues for designers of CLT structures in earthquake prone regions when equivalent static design procedure is used, are the values for the force modification factors (R-factors) for this structural system. Consequently, the objective of this study was to derive suitable ductility-based force modification factors (Rd-factors) for seismic design of CLT buildings for the National Building Code of Canada (NBCC). For that purpose, the six-storey NEESWood Capstone wood-frame building was redesigned as a CLT structure and was used as a reference symmetrical structure for the analyses. The same floor plan was used to develop models for ten and fifteen storey buildings. Non-linear analytical models of the buildings designed with different Rd-factors were developed using the SAPWood computer program. CLT walls were modelled using the output from mechanics models developed in Matlab that were verified against CLT wall tests conducted at FPInnovations. Two design methodologies for determining the CLT wall design resistance (to include and exclude the influence of the hold-downs), were used. To study the effects of fastener behaviour on the R-factors, three different fasteners (16d nails, 4x70mm and 5x90mm screws) used to connect the CLT walls, were used in the analyses. Each of the 3-D building models was subjected to a series of 22 bi-axial input earthquake motions suggested in the FEMA P-695 procedure. Based on the results, the fragility curves were developed for the analysed buildings. Results showed that an Rd-factor of 2.0 is appropriate conservative estimate for the symmetrical CLT buildings studied, for the chosen level of seismic performance.
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26 records – page 1 of 3.