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Cross Laminated Timber (CLT) Plane Structures Under Concentrated Loading from Point Supports - Shear Design including Reinforcements

https://research.thinkwood.com/en/permalink/catalogue1572
Year of Publication
2011
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Mestek, Peter
Organization
Technical University of Munich
Year of Publication
2011
Country of Publication
Germany
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Mechanical Properties
Keywords
Point-Supported
Concentrated Loads
Shear
Rolling Shear
Reinforcement
Screws
Biaxial
Language
German
Research Status
Complete
Summary
This thesis deals with the shear design of Cross Laminated Timber (CLT) elements stressed by concentrated loads which are locally reinforced by means of self-tapping screws with continuous threads. A simplified model is presented using an effective width for the calculation of the shear stresses in the vicinity of point supports or concentrated loads. Laboratory tests supply material-mechanical principles to determine the interaction of rolling shear stresses and compression perpendicular to the grain. In addition to experimental tests theoretical models are developed to examine the load bearing behaviour of CLT-elements reinforced by self-tapping screws. Preliminary tests with plate elements provide initial experience with these reinforcements under biaxial load transfer. Finally a design concept validated by means of the test results is proposed.
Online Access
Free
Resource Link
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Modeling the Coupling Effect of CLT Connections Under Bi-Axial Loading

https://research.thinkwood.com/en/permalink/catalogue2366
Year of Publication
2019
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Liu, Jingjing
Lam, Frank
Foschi, Ricardo
Li, Minghao
Year of Publication
2019
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Keywords
Coupling Effect
Biaxial loading
Degradation
Modeling
Language
English
Research Status
Complete
Series
Journal of Structural Engineering
Summary
This paper presents the modeling of coupling effect of tension and shear loading on Cross Laminated Timber (CLT) connections using a finite element based algorithm called HYST. The model idealizes the connections as a “Pseudo Nail” - elastoplastic beam elements (the nail) surrounded by compression-only spring elements (steel sheath and wood embedment). A gap size factor and an unloading stiffness degradation index of the spring elements under cyclic loading were integrated into the optimized HYST algorithm to consider the coupling effect. The model was calibrated to compare with 32 configurations of CLT angle bracket and hold-down connections tests: in tension with co-existent constant shear force, and in shear with co-existent tension force. The results showed that the proposed model can fully capture the coupling effect of typical CLT connections, considering strength degradation, unloading and reloading stiffness degradation, and pinching effect. The model provided a useful tool for nailbased timber connections and a mechanism-based explanation to understand the hysteretic behaviour of CLT connections under bi-axial loading.
Online Access
Free
Resource Link
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Timber Structures 3.0 - New Technology for Multi-Axial, Slim, High Performance Timber Structures

https://research.thinkwood.com/en/permalink/catalogue1557
Year of Publication
2016
Topic
Mechanical Properties
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Zöllig, Stefan
Frangi, Andrea
Franke, Steffen
Muster, Marcel
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Mechanical Properties
Design and Systems
Keywords
Butt-Joint
Biaxial Load Bearing
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1290-1297
Summary
Until today, all known timber building systems allow only slabs with a uniaxial load bearing action. Thereby, in comparison to normal reinforced concrete slabs, timber slabs are often thick, expensive and complicated to build. The reason for this is that there is no efficient connection technology to rigidly connect timber slab elements to each other. Alternative solutions are hybrid structural systems with concrete or steel, however, this combination of materials results in some disadvantages especially in terms of weight, ecology, construction time and costs. In the framework of a large research project a new timber slab system has been developed and already tested in first real applications. The developed slab system is designed for housing, commercial and industrial buildings. The slab system works as a flat slab carrying vertical loads biaxial and consists of timber slab elements like CLT glued together on site with a high performance butt-joint bonding technology. Research about the central slab element, the butt-joint bonding and fire tests have already been performed. The research showed the feasibility of this innovation. In 2015 a first prototype was built in Thun, Switzerland. A large three year research project started 2016 with the goal to reach market maturity.
Online Access
Free
Resource Link
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