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90 records – page 1 of 9.

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 Analytical Model for Design of Reinforcement around Holes in Laminated Veneer Lumber (LVL) Beams

https://research.thinkwood.com/en/permalink/catalogue135
Year of Publication
2013
Topic
Design and Systems
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Ardalany, Manoochehr
Fragiacomo, Massimo
Moss, Peter
Deam, Bruce
Publisher
Springer Netherlands
Year of Publication
2013
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Failure
Glued-In Rods
Model
Reinforcement
Screws
Tensile
Research Status
Complete
Series
Materials and Structures
Summary
Openings are usually required to allow services like plumbing, sewage pipes and electrical wiring to run through beams. This prevents an extra depth of the floor/ceiling, while preserving architectural considerations. The introduction of large opening causes additional tension perpendicular to grain in timber beams. The low tensile strength perpendicular to grain of wood allows crack formation. Crack propagation around the hole considerably decreases the load-carrying capacity of the beam. However, in most cases, crack formation and propagation around the hole can be prevented by the use of an appropriate reinforcement. Screw, glued-in rods, and plywood are alternative options for the reinforcement. Design of the reinforcement requires that the working mechanism of the reinforcement is fully understood and properly addressed. In addition, reinforcement should be designed for actions produced in the section of the beam weakened by the hole. The current paper uses a simple truss model around the opening to calculate the tensile force in the reinforcement. Two simple formulations for design of the reinforcement are derived and compared with numerical and experimental results, showing an overall good correspondence. The proposed truss model can be considered for incorporation in future codes of practice.
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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

Assessing the Seismic Performance of Screws Used in Timber Structures by Means of Cyclic Bending Tests

https://research.thinkwood.com/en/permalink/catalogue1946
Year of Publication
2018
Topic
Connections
Seismic
Application
Walls
Floors
Author
Izzi, Matteo
Polastri, Andrea
Nebiolo, Flavio
Luzzani, Chiara
Year of Publication
2018
Format
Conference Paper
Application
Walls
Floors
Topic
Connections
Seismic
Keywords
Screws
Bending Tests
Ductility
Monotonic Tests
Reverse Cyclic Test
Seismic Performance
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 20-23, 2018, Seoul, Republic of Korea
Summary
The low-cycle seismic performance of typical screws used in timber structures is analysed by performing monotonic and fully reversed cyclic bending tests on the threaded length of the shank. Tests considered partially threaded screws made of carbon steel with diameter varying between 6 and 10 mm. Results of the monotonic bending tests are used to assess the compliance of the screws with the requirement of ductility prescribed by EN 14592 and to define the average yielding moment of the shank. Cyclic bending tests are carried out afterwards by assuming three classes of low cycle seismic performance (S1 - low ductility class, S2 - medium ductility class and S3 - high ductility class). Results of the cyclic tests are used to evaluate the residual moment of the shank, which is then compared to the average yielding moment from monotonic tests. The outcomes of the testing programmes highlight that screws with a diameter equal to 6 mm can be assigned to a low-cycle seismic class S2, while screws with a diameter greater than or equal to 8 mm are capable of ensuring a higher seismic performance and can be assigned to a seismic class S3.
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Behavior of CLT Diaphragm Panel-to-Panel Connections with Self-tapping Screws

https://research.thinkwood.com/en/permalink/catalogue2188
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Floors
Roofs
Organization
TallWood Design Institute
Material
CLT (Cross-Laminated Timber)
Application
Floors
Roofs
Topic
Connections
Seismic
Keywords
Screws
Tall Wood
Earthquake
Research Status
In Progress
Notes
Project contact is Thomas Miller at Oregon State University
Summary
Understanding how roof and floor systems (commonly called diaphragms by engineers) that are built from Pacific Northwest-sourced cross-laminated timber (CLT) panels perform in earthquake prone areas is a critical area of research. These building components are key to transferring normal and extreme event forces into walls and down to the foundation. The tests performed in this project will provide data on commonly used approaches to connecting CLT panels within a floor or roof space and the performance of associated screw fasteners. Structural engineers will directly benefit through improved modeling tools. A broader benefit may be increased confidence in the construction of taller wood buildings in communities at greater risk for earthquakes.
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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
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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90 records – page 1 of 9.