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63 records – page 1 of 7.

Analytical Modeling of Lateral Strength and Stiffness of Inclined Self-Tapping Screw Connection

https://research.thinkwood.com/en/permalink/catalogue2651
Topic
Mechanical Properties
Connections
Author
Zhao, Ruihan
Organization
University of Alberta
Topic
Mechanical Properties
Connections
Keywords
Self-Tapping Screws
Lateral Strength
Lateral Stiffness
Withdrawal
Yield
Embedment
Research Status
In Progress
Summary
The objective of this research is to develop models for predicting lateral strength and stiffness of connections containing inclined self-tapping screws, by considering the contribution of the withdrawal and yield properties of the screws and embedment properties of the connecting members.
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An Evaluation of Strength Performance of the Edge Connections between Cross-laminated Timber Panels Reinforced with Glass Fiber-reinforced Plastic

https://research.thinkwood.com/en/permalink/catalogue2424
Year of Publication
2019
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems

An Innovative Connection System for CLT Structures: Experimental - Numerical Analysis

https://research.thinkwood.com/en/permalink/catalogue460
Year of Publication
2014
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Author
Polastri, Andrea
Angeli, Albino
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Keywords
Prefabrication
Self-Tapping Screws
X-RAD
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The paper describes experimental and numerical analyses on a completely new connection system developed for CLT (Cross Laminated Timber) constructions. The innovative solution herein proposed, named X-RAD, consists of a point-to-point mechanical connection system, fixed to the corners of the CLT panels. This connection, that is designed to be prefabricated, is made of a metal wrapping and an inner hard wood element which are fastened to the panel by means of allthreaded self-tapping screws. Such system permits to reduce significantly the number of bolts/fasteners required to assemble two or more panels together or to connect them to the foundation. This results in the enhancement of the installation process in terms of speed, quality and safety. One of the reasons that fuelled the development of the presented system, is the desire of offering a solution to those issues (e.g. to satisfy ductility and energetic dissipation requirements) commonly related to the seismic safety of timber structures. In other words there was the will of defining a system able to guarantee an adequate level of ductility and energetic dissipation.
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Application of Ductile Yield Link in Glulam Moment Connections

https://research.thinkwood.com/en/permalink/catalogue2313
Year of Publication
2018
Topic
Connections
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Beams

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
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
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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Behavior of Cross-Laminated Timber Diaphragm Panel-to-Panel Connections with Self-Tapping Screws

https://research.thinkwood.com/en/permalink/catalogue1422
Year of Publication
2017
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Sullivan, Kyle
Organization
Oregon State University
Year of Publication
2017
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Keywords
Lateral Load Resisting System
Monotonic Tests
Cyclic Tests
Strength
Stiffness
Self-Tapping Screws
International Building Code
Research Status
Complete
Summary
The goal of this project is to contribute to the development of design values for cross-laminated timber (CLT) diaphragms in the seismic load-resisting system for buildings. Monotonic and cyclic tests to determine strength and stiffness characteristics of 2.44 m (8 ft) long shear connections with common self-tapping screws were performed. Understanding and quantifying the behavior of these shear connections will aid in developing design provisions in the National Design Specification for Wood Construction and the International Building Code so structural engineers can use CLT more confidently in lateral force-resisting systems and extend the heights of wood buildings. Experimental strength-to-design strength ratios were in the range of 2.1 to 8.7. In the ASCE 41 acceptance criteria analysis, the m-factors 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, where screws were installed in withdrawal, shear, shear, and withdrawal, performed exceptionally well with both high, linear-elastic, initial stiffness, and ductile, post-peak behavior.
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Behaviour of Mass Timber Panel-Concrete Connections with Inclined Self-Tapping Screws and Insulation Layer

https://research.thinkwood.com/en/permalink/catalogue1984
Year of Publication
2018
Topic
Mechanical Properties
Connections
Material
Timber-Concrete Composite
CLT (Cross-Laminated Timber)
Application
Floors
Author
Abdul Hamid Mirdad, Md
Chui, Ying Hei
Year of Publication
2018
Format
Conference Paper
Material
Timber-Concrete Composite
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Connections
Keywords
Self-Tapping Screws
Insulation
Mid-Rise
High-Rise
Stiffness
Strength
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
The Mass Timber Panel-Concrete (MTPC) composite floor system considered in this paper consists of a Mass Timber Panel (MTP) connected to reinforced concrete slab with Self-Tapping Screw (STS) connector and a sound insulation layer in between. This type of composite floor system is intended for mid- to high-rise building applications. Two types of MTPs with normal weight concrete, two insulation thicknesses, two screw embedment lengths and two screw angles were investigated through connection tests to characterize connection stiffness and strength. The main goal of this connection test program was to provide preliminary test data to assist in the development of a model to predict connections lateral stiffness and strength under consideration of insulation thickness, screw angle, withdrawal and embedment properties of screws in MTP. Connection test results show that screws at an insertion angle of 30° have a higher stiffness and strength along with a larger embedment length compared to the screws at a 45° angle and smaller embedment length. Stiffness seemed to be more susceptible to the influence of presence of insulation compared to strength with 40-65% reduction of stiffness and 10-20% reduction of strength were noticed for an insulation thickness of 5 mm. Screws in CLT showed higher strength while screws in CLP showed higher stiffness but the difference is insignificant.
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Block Shear Failure Mode of Axially Loaded Groups of Screws

https://research.thinkwood.com/en/permalink/catalogue1512
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Solid-sawn Heavy Timber
Author
Mahlknecht, Ursula
Brandner, Reinhard
Augustin, Manfred
Year of Publication
2016
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Solid-sawn Heavy Timber
Topic
Connections
Mechanical Properties
Keywords
Self-Tapping Screws
Block Shear Model
Stiffness
Strength
Bending Stresses
Axially-Loaded
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 362-371
Summary
Self-tapping screws are efficient and flexible fasteners, applicable for many types of connections. Investigations on axially loaded groups of screws pointed out, that small spacing between the screws lead to block shear failure mode. So far, block and plug shear failure mode are only analysed for laterally loaded fasteners. Corresponding models cannot be simple transferred to primary axially loaded screws, because of their load insertion continuously along the effective thread featuring a thread-fibre angle perpendicular or with an angle to grain. Results gained by means of two different test configurations, with constant 90° thread-fibre angle but different configurations of group of screws and support conditions are presented. A block shear model is presented, and for mean values for stiffness and strength properties as model parameters are discussed together with values for parameters related to the force distribution over the effective thread length for the first test configuration. Agreement between model and test results was found on a conservative basis. As outlook, considerations of additional bending stresses as well as parameter optimisation are seen as prerequisites and next steps for further model improvement and practicality.
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Comparison of Glulam Post-To-Beam Connections Reinforced by two Different Dowel-Type Fasteners

https://research.thinkwood.com/en/permalink/catalogue55
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
He, Minjuan
Liu, Hui-Fen
Publisher
ScienceDirect
Year of Publication
2015
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Reinforcement
Rods
Seismic
Self-Tapping Screws
Moment Resistance
Research Status
Complete
Series
Construction and Building Materials
Summary
In this paper, the performance improvement of glulam post-to-beam connections reinforced by plain round rods (PRRs) and self-tapping screws (STSs) were compared. Five non-reinforced post-to-beam bolted connections, five PRR-reinforcing connections and five STS-reinforcing connections were experimentally investigated under monotonic and low frequency cyclic loading. Their stiffness, ductility, moment resistance capacity, failure modes and seismic behavior were analyzed. The findings indicated that both of these two reinforcements could mitigate wood splitting, and change the failure mode from brittle failure to ductile failure. The maximum moment and failure rotation of PRR-reinforcing connection were increased by 29% and 6% respectively, compared with those of non-reinforced connection. In addition, those of STS-reinforcing connection increased by 86% and 145% respectively. Furthermore, the comparison of PRR-reinforcing and STS-reinforcing connections indicated that the connection ductility reinforced by self-tapping screws enhanced more significantly; 106% higher than that of PRR-reinforcing connection. Moreover, under the low frequency cyclic loading, PRR-reinforcing and STS-reinforcing connections dissipated more energy (336% and 641% respectively) with a lower stiffness degeneration rate and a higher equivalent viscous damping ratio than those of non-reinforced connection. Besides, the dissipation energy and equivalent viscous damping ratio of STS-reinforcing connection were larger than those of PRR-reinforcing connection.
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Composite action in mass timber floor and beam systems connected with self-tapping wood screws

https://research.thinkwood.com/en/permalink/catalogue3010
Year of Publication
2020
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Natalini, Giulia
Organization
University of British Columbia
Year of Publication
2020
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Keywords
Push-Out Tests
Bending Tests
Self-Tapping Screws
T-beam
Research Status
Complete
Summary
One of the challenges in mass timber construction is the design of efficient floor systems. This thesis focuses on studying composite T-beams, connecting Spruce-Pine-Fir Cross Laminated Timber (CLT) panels and Douglas-Fir Glued-Laminated timber (glulam) beams. In this study, three different types of self-tapping wood screws (ASSY SK, ASSY Ecofast, and ASSY VG), inserted at different angles, were investigated. Firstly, small-scale experimental tests were performed to investigate the strength and stiffness of the screws when submitted to lateral shear loads. It was found that the most promising fastener was the ASSY VG and that changing the angle of installation of the screws from 90° to the wood grain, to 45°, increased the strength and the stiffness of the studied connection. Secondly, full-scale composite beams experimental tests were completed to validate mechanistic-based and computational methods used to predict the effective bending stiffness of the composite T-beam. A degree of composite action achieved for the experimental T-beams was calculated through the studied methods. It was found that the studied T-beam achieved a moderately high percentage of composite action. Moreover, the methods were compared in terms of prediction accuracy, computational difficulty, required number of parameters, and versatility. Finally, parametric analyses were completed to gain insight into the structural performance of the composite beam when varying the number of CLT plies, the width of the CLT panel and of the glulam beams, as well as the length of the T-beam. Results indicate, conservatively, that the proposed connection, with a 3-ply CLT panel and a 130x190mm glulam beam, can be used to span 6m, maintaining a flange width of 2.8m. The results also suggest that with a 5-ply CLT panel and a 365x190mm glulam beam, it is possible to manufacture a 10m long T-beam that spans 3m laterally and supports live loads compatible with office use and occupancy.
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63 records – page 1 of 7.