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19 records – page 1 of 2.

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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A Composite System Using Ultra High-Performance Fibre-Reinforced Concrete and Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1420
Year of Publication
2016
Topic
Mechanical Properties
Acoustics and Vibration
Connections
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Author
Chen, Mengyuan
Organization
University of Toronto
Year of Publication
2016
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Acoustics and Vibration
Connections
Keywords
Ultra-High-Performance Fibre-Reinforced Concrete
Push-Out Tests
Glued-In Rods
Bending Tests
Vibration Tests
Span Limits
Research Status
Complete
Summary
The application of cross-laminated timber (CLT) as floor panels is limited by excessive deflection and vibration. A composite system combining CLT and ultra high-performance fibre-reinforced concrete (UHPFRC) was developed to extend span limits. Push-off tests were conducted on different connectors, and a glued-in rod connector was chosen and further refined for the proposed system. Static bending tests and free vibration tests were conducted on bare CLT panels and two composite specimens. By comparing the results, it is concluded that the proposed system considerably extend the span limits of CLT panels.
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Connection Performance for LVL-Concrete Composite Floor System

https://research.thinkwood.com/en/permalink/catalogue292
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Author
Fong Lee, Yen
Abd. Ghafar, Nor
Abd. Rahman, Norashidah
Yeoh, David
Organization
International Integrated Engineering Summit (IIES)
Year of Publication
2015
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Topic
Connections
Mechanical Properties
Keywords
Push-Out
Notch Connections
Failure
Strength
Stiffness
Ultimate Limit States
Serviceability Limit States
Conference
IIES 2014
Research Status
Complete
Notes
December 1-4, 2014, Johor, Malaysia
Summary
The LVL-concrete composite (LCC) structure is a hybrid in system which the LVL member is well connected to the concrete slab by a connector to produce composite action. Various types of connector with different stiffness and shear capacity are available in the market currently. The stiffness of the connector is identified through the push-out experiment. The notch connections for LVL concrete composite beams have higher stiffness and strength compared to mechanical fasteners. This paper discusses the experimental results of symmetrical push-out tests on 3 different types of connector, 150mm rectangular notch with 10mm diameter screw, 100mm rectangular notch with 8mm diameter screw and 100mm triangular notch with 8mm diameter screw. The experimental test was shear push out to failure and the type of failure was discussed. The 150mm rectangular notch was found to be strongest among all and low cost. The 100mm rectangular notch was found to be slightly stiffer than 100mm triangular notch but 100mm triangular notch is easier to construct with only 2 cut. The maximum strength and stiffness at ultimate limit states and serviceability limit states of each type of connection were discussed in this paper.
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Deconstructable Hybrid Connections for the Next Generation of Prefabricated Mass Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2809
Year of Publication
2021
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Hybrid Building Systems
Shear Walls
Author
Shulman, Samuel
Loss, Cristiano
Organization
University of British Columbia
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Floors
Hybrid Building Systems
Shear Walls
Topic
Connections
Keywords
Steel Rods
Epoxy
Push-Out-Shear Tests
Prefabrication
Disassembly
Reuse
Research Status
Complete
Summary
Timber has been used for building construction for centuries, until the industrial revolution, when it was often replaced by steel and concrete or confined to low-rise housings. In the last thirty years however, thanks to the development of mass timber products and new global interest in sustainability, timber has begun to make a resurgence in the building industry. As building codes and public perception continues to change, the demand for taller and higher-performance timber buildings will only grow. Thus, a need exists for new construction technology appropriate for taller mass timber construction, as well as for fabrication and deconstruction practices that respect wood’s inherent sustainable nature. With this in mind, this research program aims to develop a new hybrid shear connection for mass timber buildings that allows for easy construction, deconstruction, and reuse of the structural elements. This report includes results of Phase 1, which focused on connections consisting of partially threaded 20M and 24M steel rods bonded into pockets formed in CLT and surrounded by thick crowns of high-strength three-component epoxy-based grout. A total of 168 specimens were designed and fabricated, and push-out shear tests carried out with a displacement-controlled monotonic loading protocol. Strength and stiffness values were assessed and effective failure modes in specimens identified. These latter, along with the recorded load-deformation curves, indicate that it is possible to develop mechanics-based design models and design formulas akin to those already used for typical dowel-type fastener timber connections. Additionally, the specimens were easily fabricated in the lab and quickly fastened to the test jig by means of nuts and washers, suggested such connections have a strong potential for prefabrication, disassembly, and reuse.
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Deconstructable Timber-Concrete Composite Connectors

https://research.thinkwood.com/en/permalink/catalogue2740
Year of Publication
2020
Topic
Connections
Material
Timber-Concrete Composite
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Derikvand, Mohammad
Fink, Gerhard
Publisher
Society of Wood Science & Technology
Year of Publication
2020
Format
Conference Paper
Material
Timber-Concrete Composite
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Connections
Keywords
Deconstructable Connections
Deconstructable Connector
TCC
Push-Out Tests
Shear Strength
Slip Modulus
Failure Mode
Self-Tapping Screws
Conference
Society of Wood Science and Technology International Convention
Research Status
Complete
Summary
The application of deconstructable connectors in timber-concrete composite (TCC) floors enables the possibility of disassembly and reuse of timber materials at the end of building’s life. This paper introduces the initial concept of a deconstructable TCC connector comprised of a self-tapping screw embedded in a plug made of rigid polyvinyl chloride and a level adjuster made of silicone rubber. This connection system is versatile and can be applied for prefabrication and in-situ concrete casting of TCC floors in both wet-dry and dry-dry systems. The paper presents the results of preliminary tests on the shear performance of four different configurations of the connector system in T-section glulam-concrete composites. The shear performance is compared to that of a permanent connector made with the same type of self-tapping screw. The failure modes observed are also analyzed to provide technical information for further optimization of the connector in the future.
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Development of Steel-Timber Composite System for Large Scale Construction

https://research.thinkwood.com/en/permalink/catalogue1696
Year of Publication
2016
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Hassanieh, Amirhossein
Valipour, Hamid
Bradford, Mark
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Mechanical Properties
Connections
Keywords
Short-term
Ultimate Limit States
Push-Out Tests
Failure Modes
Four Point Bending Test
Strength
Stiffness
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4322-4331
Summary
In this paper a novel and efficient structural system, that comprises steel beams and prefabricated timber slabs is developed and tested under short-term service and ultimate limit state loading conditions. In the proposed steeltimber composite (STC) system, bolt and coach screws are employed to transfer shear between steel beam and prefabricated timber slab and provide a composite connection. A series of experimental push-out tests were carried out on cross-banded LVL-Steel and CLT-Steel hybrid specimens to investigate the behaviour of different connection types. Furthermore, the load-deflection response of full-scale STC beams was captured by conducting 4-point bending tests on STC beams. The failure modes of connections and composite beams have been monitored and reported. The results illustrate advantages of using timber panels in conjunction with steel girders in terms of increasing strength and stiffness of composite beams
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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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Experimental Study of Aluminium-Timber Composite Bolted Connections Strengthened with Toothed Plates

https://research.thinkwood.com/en/permalink/catalogue3162
Year of Publication
2022
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Chybinski, Marcin
Polus, Lukasz
Organization
Poznan University of Technology
Editor
Garbowski, Tomasz
Marek, Aleksander
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Aluminium-Timber Composite Structures
Aluminium Alloy
Engineering Wood Products
Toothed Plate
Bolted Connection
Shear Connection
Push-out Test
Research Status
Complete
Series
Materials
Summary
This paper presents the first experimental study of the load-slip behaviour of aluminium-timber composite bolted connections reinforced with toothed plates. The effectiveness of the strengthening was evaluated in laboratory push-out tests. The push-out test samples consisted of laminated veneer lumber panels, aluminium alloy I-beams, and bolts (grade 8.8 10 mm × 125 mm and 12 mm × 135 mm bolts, grade 5.8 10 mm × 125 mm and 12 mm × 135 mm bolts). A group of 16 specimens had toothed plates as additional reinforcement, while 16 specimens had no reinforcement. The impact of the bolt diameter (10 and 12 mm) and bolt grade (5.8 and 8.8) on the behaviour of the connections was also analysed. The values of the ultimate load and the slip modulus for the bolted connections with grade 8.8 10 mm and 12 mm bolts and with grade 5.8 12 mm bolts reinforced by toothed-plate connectors were comparable to the values for the non-reinforced connections. This was because, in the case of grade 8.8 10 mm × 125 mm and 12 mm × 135 mm bolts and grade 5.8 12 mm × 135 mm bolts, the laminated veneer lumber (LVL) slabs split both in the reinforced and non-reinforced connections. The toothed-plate connectors reduced timber destruction in the bearing zones in the LVL slabs. However, they did not protect the LVL slabs against splitting. Therefore, the impact of the toothed plate connectors on the stiffness and strength of the bolted connections with grade 8.8 10 mm and 12 mm bolts and with grade 5.8 12 mm bolts analysed in this paper was found to be negligible. In the case of grade 5.8 10 mm bolts, the LVL slabs did not split. The mean slip modulus k0.6 of the connections with grade 5.8 10 mm bolts reinforced with toothed plate connectors was 2.9 times higher than that of the non-reinforced connections. However, the strength of the connections with grade 5.8 10 mm bolts was 1.2 times lower after reinforcing. This was because the shanks of the bolts were sheared faster in the reinforced connections than in the non-reinforced connections as a result of the bolt shanks being under the bearing pressure of the aluminium flange, the LVL slab, and the toothed-plate flange. This situation did not occur for the remaining connections because they had a higher strength (grade 8.8 bolts) or a larger diameter (12 mm), and their bolts were less prone to cutting off. The investigated load–slip curves of the reinforced bolted connections can be used for designing and numerical modelling of aluminium-timber composite beams with this type of connection.
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Hybrid CLT-Based Modular Construction Systems for Prefabricated Buildings

https://research.thinkwood.com/en/permalink/catalogue1901
Year of Publication
2018
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Wood Building Systems
Floors
Walls
Author
Loss, Cristiano
Tannert, Thomas
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Wood Building Systems
Floors
Walls
Topic
Design and Systems
Keywords
Hybrid Structures
Composite Structures
Diaphragms
Connections
Push-Out Tests
Bending Tests
Full-Scale
Sustainability
Conference
International Association for Bridge and Structural Engineering Symposium
Research Status
Complete
Notes
September 19-21, 2018, Nantes, France
Summary
Contemporary structures are required to be earthquake-resistant, sustainable and flexible to changing occupancy needs over time. Hybrid wood-based construction systems are promising solutions for modern buildings and research for cost-efficient systems is underway to compete with more traditional and widely spread non-wood building systems. This paper presents an innovative modular and prefabricated wood-based hybrid construction technology. It is a dry solution obtained by fastening on-site steel frames and composite CLT-steel members using only bolts and screws. The main results obtained from a comprehensive experimental programme with focus on the in-plane and out-of-plane behaviour of floors are reviewed. The influence of connections on the response of floors is discussed. The findings are of practical relevance with direct impacts on other applications.
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In-Plane Stiffness of Timber Floors Strengthened with CLT

https://research.thinkwood.com/en/permalink/catalogue516
Year of Publication
2015
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Branco, Jorge
Kekeliak, Milos
Lourenço, Paulo
Publisher
Springer Berlin Heidelberg
Year of Publication
2015
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Connections
Keywords
Full Scale
Numerical model
Push-Out Tests
Stiffness
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
Five full-scale timber floors were tested in order to analyse the in-plane behaviour of these structural systems. The main objective was an assessment of the effectiveness of in-plane strengthening using cross-laminated timber (CLT). To that end, one unstrengthened specimen (original), one specimen strengthened with a second layer of floorboards, two specimens strengthened with three CLT panels, and one specimen strengthened with two CLT panels, were tested. A numerical analysis was then performed in order to analyse the composite behaviour of the timber floors in more detail. Due to its importance as regards composite behaviour, the first phase of the experimental programme was composed of push out tests on specimens representing the shear connection between the timber beams and the CLT pan CLT panels. This paper describes els. This paper describes the tests performed and the numerical modelling applied the tests performed and the numerical modelling applied to evaluate the composite behaviour of the strengthened timber floors. The use of CLT panels is revealed to be an effective way to increase the in-plane stiffness of timber floors, through which the behaviour of the composite structure can be significantly changed, depending on the connection applied, or modified as required.
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19 records – page 1 of 2.