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10 records – page 1 of 1.

Performance of Self-Tapping Screws and Threaded Steel Rods in Shear Reinforcement of Glulam Beams

https://research.thinkwood.com/en/permalink/catalogue1628
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Jockwer, Robert
Steiger, René
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Norway Spruce
Reinforcement
Self-Tapping Screws
Threaded Steel Rod
Stiffness
Strength
Load Carrying Capacity
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 2813-2822
Summary
Norway spruce glulam beams with artificial horizontal slits of different length and depth were reinforced using self-tapping screws and threaded steel rods in order to restore their load-carrying capacity and stiffness. The study aimed at evaluating the effects of strength and stiffness of the applied reinforcing elements on the load-carrying capacity and stiffness of glulam beams after retrofitting. Self-tapping screws and threaded steel rods of different diameter have been evaluated in the study and different numbers of reinforcing elements have been applied. Shear failure of the beams with artificial slits of different depth was provoked in loading cycles with stepwise installation of the reinforcing elements in the beam parts failed in the preceding test. The reinforcing effect of the tested self-tapping screws and threaded steel rods reached and partly exceeded the estimated level calculated with selected analytical models. Unfavourable structural behaviour arose in some cases from crack opening during installation of the rods causing a very low initial stiffness. Comparison of test results to calculations of stiffness and load-carrying capacity of the reinforced beams applying the -method, the shear analogy method and a truss model revealed that the -method and the shear analogy method provided the best estimates of strength / stiffness of the reinforced beams.
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Effect of Inclined Self-Tapping Screws Connecting Laminated Veneer Lumber on the Shear Resistance

https://research.thinkwood.com/en/permalink/catalogue2479
Year of Publication
2019
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)

Influence of Moisture Content and Gaps on the Withdrawal Resistance of Self Tapping Screws in CLT

https://research.thinkwood.com/en/permalink/catalogue299
Year of Publication
2014
Topic
Connections
Mechanical Properties
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Silva, Catarina
Ringhofer, Andreas
Branco, Jorge
Lourenço, Paulo
Schickhofer, Gerhard
Organization
National Congress of Experimental Mechanics
Year of Publication
2014
Country of Publication
Portugal
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Moisture
Keywords
Self-Tapping Screws
Withdrawal
Gaps
Moisture Content
Language
English
Conference
9th National Congress of Experimental Mechanics
Research Status
Complete
Notes
October 15-17, 2014, Aveiro, Portugal
Summary
Self-tapping screws (STS) have been proclaimed as the easiest solution for structural timber connections, in special for cross laminated timber (CLT) constructions. In order to understand deeply the composite model “CLT-STS”, an experimental campaign which comprised 270 withdrawal tests was carried out. Maximum withdrawal load capacity of self-tapping screws inserted in plane side of a three layered CLT panel was evaluated considering three main parameters: moisture levels of CLT (i), number of gaps (ii) and the width of gaps (iii). Regarding (i), connections were tested with CLT at 8%, 12% and 18% of moisture content. Concerning (ii) and (iii), different test configurations with 1, 2 and 3 gaps, with 0 or 4mm, were tested. The influences of moisture content and number of gaps were modeled. Further a correlation between test results and a prediction model developed by Uibel and Blaß (2007) has been proposed.
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Load Bearing Behaviour of Self-Tapping Screws in Laser-Drilled Guideholes

https://research.thinkwood.com/en/permalink/catalogue1501
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Trautz, Martin
Koj, Christoph
Uchtmann, Hermann
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Self-Tapping Screws
Laser Drilling
Pull-Out Strength
Guideholes
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 270-277
Summary
Self-tapping screws, used as efficient reinforcements or connectors for timber and glulam structures, tend to “stray” from the designated axis when long and slender screws are applied. To provide a highly precise installation, the predrilling of guideholes using laser radiation has been examined. While laser cutting is already common in machining thin wood-based panels (plywood, chipboard, etc.), laser drilling has not yet been applied for higher drill depths. Based on preliminary tests, pulsed fibre laser radiation was used to drill through glulam species in different angles to the wood fibre direction to examine the geometry and thermal modification of the boreholes. Thereafter self-tapping screws were installed in the laser-drilled guideholes and their pull-out resistance was determined in comparison to screws installed in mechanically drilled holes and screws installed without predrilling. The results of the tests show the high potential for further development of this innovative wood processing method in timber construction.
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Shear Connections with Self-Tapping-Screws for Cross-Laminated-Timber Panels

https://research.thinkwood.com/en/permalink/catalogue1531
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Hossain, Afrin
Popovski, Marjan
Tannert, Thomas
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Self-Tapping Screws
Joints
Quasi-Static
Capacity
Stiffness
Yield Strength
Ductility
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 756-763
Summary
The research presented in this paper examines the performance of 3-ply and 5-ply Cross-laminated Timber (CLT) panels connected with Self-tapping Screws (STS). Different conventional joint types (surface spline with STS in shear and half-lap joints with STS in either shear or withdrawal) along with two innovative solutions were evaluated in a total of 198 quasi-static tests. The first novel assembly used STS with double inclination of fasteners in butt joints; the second was a combination of STS in withdrawal and shear in lap joints. The joint performance was evaluated in terms of capacity, stiffness, yield strength, and ductility. The results confirmed that joints with STS in shear exhibited high ductility but low stiffness, whereas joints with STS in withdrawal were found to be stiff but less ductile. Combining the shear and withdrawal action of STS led to high stiffness and high ductility.
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Shear Connections with Self-Tapping-Screws for Cross-Laminated-Timber Panels

https://research.thinkwood.com/en/permalink/catalogue432
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Hossain, Afrin
Lakshman, Ruthwik
Tannert, Thomas
Organization
Structures Congress
Publisher
American Society of Civil Engineers
Year of Publication
2015
Country of Publication
United States
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Mechanical Properties
Keywords
Ductility
Self-Tapping Screws
Stiffness
Strength
Vertical Shear Loading
Mid-Scale
Quasi-Static
Shear Tests
Language
English
Conference
Structures Congress 2015
Research Status
Complete
Notes
April 23–25, 2015, Portland, Oregon, USA
Summary
Cross-Laminated-Timber (CLT) is increasingly gaining popularity in residential and non-residential applications in North America. To use CLT as lateral load resisting system, individual panels need to be connected. In order to provide in-plane shear connections, CLT panels may be joined with a variety of options including the use of self-tapping-screws (STS) in surface splines and half-lap joints. Alternatively, STS can be installed at an angle to the plane allowing for simple butt joints and avoiding any machining. This study investigated the performance of CLT panel assemblies connected with STS under vertical shear loading. The three aforementioned options were applied to join 3ply and 5-ply CLT panels. A total of 60 mid-scale quasi-static shear tests were performed to determine and compare the connection performance in terms of strength, stiffness, and ductility. It was shown that – depending on the screw layout – either very stiff or very ductile joint performance can be achieved.
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High Performance Cross-Laminated-Timber Shear Connection with Self-Tapping Screw Assemblies

https://research.thinkwood.com/en/permalink/catalogue504
Year of Publication
2014
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Danzig, Ilana
Closen, Maximilian
Tannert, Thomas
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Mechanical Properties
Keywords
Self-Tapping Screws
Panels
Full Scale
Quasi-Static
Reverse Cyclic Loading
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The research presented in this paper examines the performance of a shear connection using self-tapping screws (STS) in 3-ply Cross-Laminated Timber (CLT) panels. CLT panels were connected with STS assemblies at an inclined angle in two directions. The capacity of the STS assemblies was tested for the purpose of designing a CLT roof diaphragm of a large storage facility where a high-performance and low-manufacturing-cost solution was required. A total of eleven full-scale specimens were subjected to quasi-static and reversed-cyclic shear loading. Resulting forcedisplacement and hysteretic curves were used to determine an equivalent energy elastic-plastic curve based on ASTM E2126-11 procedures to estimate assembly yield strength, yield displacement, and ductility ratio. The performance in terms of strength and stiffness was excellent, and the STS provided the required ductility for the system to be used in seismic applications. Static yield strength averaged 80kN/m with an average ductility ratio of 7.7 while cyclic yield strength averaged 68kN/m with an average ductility ratio of 4.1. The data obtained allows engineers to specify low-cost lateral load resisting connection systems for large scale CLT structures.
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Behavior of Cross-Laminated Timber Diaphragm Connections with Self-Tapping Screws

https://research.thinkwood.com/en/permalink/catalogue1288
Year of Publication
2018
Topic
Connections
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Author
Sullivan, Kyle
Miller, Thomas
Gupta, Rakesh
Publisher
ScienceDirect
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Seismic
Keywords
Seismic Force Resisting System
Monotonic Tests
Cyclic Tests
Strength
Stiffness
Shear Connections
Self-Tapping Screws
Language
English
Research Status
Complete
Series
Engineering Structures
Summary
Monotonic and cyclic tests were carried out to determine strength and stiffness characteristics of 2.44 m (8 ft) long shear connections with 8 mm and 10 mm diameter self-tapping screws. The goal of this research is tocompare test values of cross-laminated timber (CLT) diaphragm connections in seismic force-resisting systems tothe design values calculated from formulas in the National Design Specification for Wood Construction (USA)and the Eurocode. Understanding and quantifying the behavior of these shear connections will provide structural engineers with increased confidence in designing these components, especially with regard to the seismic forceresisting systems. Ratios of the experimental yield strength (from the yield point on the load-deflection curve) to factored design strength were in the range of 2.1–6.1. In the ASCE 41-13 acceptance criteria analysis, the mfactors for the Life Safety performance level in cyclic tests ranged from 1.6 to 1.8 for surface spline connections and from 0.9 to 1.7 for cyclic half-lap connections. The half-lap connections with a unique combination of angled and vertical screws performed exceptionally well with both high, linear elastic initial stiffness and ductile, postpeak behavior.
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Seismic Performance of Post-Tensioned Moment-Resisting Portal Frames

https://research.thinkwood.com/en/permalink/catalogue1973
Year of Publication
2018
Topic
Seismic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Wood Building Systems

Structural Performance of Portal Frame Constructed with Japanese Cedar Glulam

https://research.thinkwood.com/en/permalink/catalogue698
Year of Publication
2014
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Yeh, Min-Chyuan
Lin, Yu-Li
Deng, Shu-Yu
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Design and Systems
Mechanical Properties
Keywords
Cedar
Portal Frame
Lateral Cyclic Load
Pins
Moment Resistance
Stress Distribution
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
Feasibility of using rapid grown Japanese cedar glulam for constructing a portal frame was examined. A 2500x3000-mm portal frame was constructed with 140x305-mm glulam members and subjected to a lateral cyclic load. The connections between post and beam members were fastened with 8 16-mm pins. Resulted moment resistance of the frame fastened with pins in square placement performed better than that with in circular placement. While the inserted metal plate in L-type showed higher initial stiffness and energy absorption than that in straight metal plate. The stress distribution of glulam post indicated shifts of neutral axis and deflection point as the cyclic load increases.
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10 records – page 1 of 1.