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7 records – page 1 of 1.

Brittle failure of laterally loaded self-tapping screw connections for cross-laminated timber structures

https://research.thinkwood.com/en/permalink/catalogue3120
Year of Publication
2022
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Author
Azinovic, Boris
Cabrero, José Manuel
Danielsson, Henrik
Pazlar, Tomaž
Organization
Slovenian National Building and Civil Engineering Institute
University of Navarra
Lund University
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Keywords
Brittle Failure
Analytical Model
Overstrength
Research Status
Complete
Series
Engineering Structures
Summary
The performance of structural timber connections is of utmost importance since they control the global response of the building. A ductile failure mechanism on the global scale is desirable, especially in the design of structures in seismic areas, where dissipative components in which ductile failure modes need to be ensured are considered. Therefore, the knowledge of possible brittle failure modes of connections is crucial. The paper investigates the brittle failures of laterally loaded dowel-type connections in cross-laminated timber subjected to tensile load in a lap joint configuration through experimental investigations and analytical estimations. A set of 13 different test series has been performed with fully threaded self-tapping screws of 8 mm diameter and different lengths (40 to 100 mm) in cross-laminated timber composed of 3 or 5 layers (layer thickness range from 20 to 40 mm), giving rise to the activation of different brittle failure modes at different depths. Plug shear was among the most typically observed failure modes. A previously proposed model for the brittle capacity was applied to the tested connections at the characteristic level. As shown by the performed statistical analysis, the existing model is not reliable and mainly unconservative. A very low performance is observed (CCC = 0.299), but with a good correlation (c = 0.750) for the tests in the parallel direction. Further research work is required to improve the current model predictions and to gain a better understanding of the underlying resisting mechanisms.
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Cyclic Response of Insulated Steel Angle Brackets Used for Cross-Laminated Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2765
Year of Publication
2021
Topic
Seismic
Acoustics and Vibration
Connections
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Kržan, Meta
Azinovic, Boris
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Seismic
Acoustics and Vibration
Connections
Keywords
Angle Bracket
Sound Insulation
Insulation
Monotonic Test
Cyclic Tests
Wall-to-Floor
Stiffness
Load Bearing Capacity
Shear
Tensile
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
In cross-laminated timber (CLT) buildings, in order to reduce the disturbing transmission of sound over the flanking parts, special insulation layers are used between the CLT walls and slabs, together with insulated angle-bracket connections. However, the influence of such CLT connections and insulation layers on the seismic resistance of CLT structures has not yet been studied. In this paper, experimental investigation on CLT panels installed on insulation bedding and fastened to the CLT floor using an innovative, insulated, steel angle bracket, are presented. The novelty of the investigated angle-bracket connection is, in addition to the sound insulation, its resistance to both shear as well as uplift forces as it is intended to be used instead of traditional angle brackets and hold-down connections to simplify the construction. Therefore, monotonic and cyclic tests on the CLT wall-to-floor connections were performed in shear and tensile/compressive load direction. Specimens with and without insulation under the angle bracket and between the CLT panels were studied and compared. Tests of insulated specimens have proved that the insulation has a marginal influence on the load-bearing capacity; however, it significantly influences the stiffness characteristics. In general, the experiments have shown that the connection could also be used for seismic resistant CLT structures, although some minor improvements should be made.
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Experimental and Numerical Analysis of Flexible Polymer Connections for CLT Buildings

https://research.thinkwood.com/en/permalink/catalogue2057
Year of Publication
2018
Topic
Connections
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Azinovic, Boris
Kramar, Miha
Pazlar, Tomaž
Gams, Matija
Kwiecien, Arkadiusz
Weckendorf, Jan
Sustersic, Iztok
Organization
Cracow University of Technology
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Mechanical Properties
Seismic
Keywords
Pull-Pull Tests
Cyclic Loading
Energy Dissipation
Glued-In Rods
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
This paper explores the possibility of using flexible adhesives to dissipate energy in CLT buildings during earthquakes. In the first series of tests, a rod glued in a CLT panel with flexible adhesive was investigated. The connection was tested in pull-pull configuration using cyclic, tension-only loading. Different rod diameters and different thicknesses of the glue layer were tested. The tests have shown that the adhesive can resist large deformations and exhibits fairly large energy dissipation capacity. Based on the test results the numerical analyses were performed to test the behaviour of the connection when applied in CLT buildings. Existing constitutive models available in OpenSees software were used to simulate the specific hysteretic behaviour of the connection. The results have shown that the CLT wall anchored with "flexible" glued-in rods would have a significant energy dissipation capacity if a sufficient number of them were used as the hold-down devices. Such system could be used to dissipate energy in seismic areas.
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Experimental Investigation of the Axial Strength of Glued-in Rods in Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2230
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)

Glued-in Rods in Cross Laminated Timber – Numerical Simulations and Parametric Studies

https://research.thinkwood.com/en/permalink/catalogue2231
Year of Publication
2019
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)

The influence of flexible sound insulation layers on the seismic performance of cross laminated timber walls

https://research.thinkwood.com/en/permalink/catalogue2882
Year of Publication
2021
Topic
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Azinovic, Boris
Pazlar, Tomaž
Kržan, Meta
Organization
ZAG Ljubljana
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Mechanical Properties
Seismic
Keywords
Angle Bracket
Elastomer Sound Insulation
Racking Test
Lateral Load-bearing Capacity
Research Status
Complete
Series
Journal of Building Engineering
Summary
This paper presents the results of an experimental campaign investigating the seismic behaviour of full-size cross laminated timber (CLT) wall systems with sound-insulated shear-tension angle brackets. The main aim of the study was to investigate the influence of more and less flexible soundproofing bedding under the CLT wall. The paper shows a comparison of lateral load-bearing capacity, displacement capacity, ductility and stiffness obtained from racking tests on uninsulated specimens and specimens with various types of bedding insulation and levels of vertical load. Moreover, an analytical procedure to estimate the lateral load-displacement response of CLT walls with bedding insulation is proposed. This model is verified by direct comparison to the experimentally determined lateral load-displacement backbone curves. The results show that the elastomeric bedding does not have a significant effect on the bearing capacity of the wall system tested, but it reduces the stiffness and increases the displacement capacity. Due to the large decrease in stiffness, the insulation causes an overall reduction in ductility. The analytical estimation proposed was able to capture the reduction in lateral stiffness and adequately predict the load-bearing capacity.
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Mechanical performance of timber connections made of thick flexible polyurethane adhesives

https://research.thinkwood.com/en/permalink/catalogue3130
Year of Publication
2021
Topic
Connections
Author
Pecnik, Jaka Gašper
Gavric, Igor
Sebera, Václav
Kržan, Meta
Kwiecien, Arkadiusz
Zajac, Boguslaw
Azinovic, Boris
Organization
University of Primorska
Slovenian National Building and Civil Engineering Institute
Cracow University of Technology
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Topic
Connections
Keywords
Flexible Adhesive
Timber Connection
Polyurethane
Double Lap-shear
Cyclic Loading
Energy Dissipation
Research Status
Complete
Series
Engineering Structures
Summary
This study investigates timber connections with flexible polyurethane adhesives, which prove to have the potential for timber-adhesive composite structures without mechanical connections for seismic regions. Results of conducted cyclic double lap-shear adhesive timber joints tests were compared with available experimental results on timber connections with standard mechanical dowel-type fasteners and with results of numerical finite element analysis. The study found that the shear strength, elastic stiffness and strength degradation capacity of the flexible adhesive connections were significantly higher compared to mechanical fasteners commonly used in seismic-resistant timber connections. The latter, however, manifested larger ultimate displacements but also yielded at lower displacements.
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7 records – page 1 of 1.