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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.
Online Access
Free
Resource Link
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Fire resistance of unprotected cross-laminated timber (CLT) floor assemblies produced in the USA

https://research.thinkwood.com/en/permalink/catalogue2063
Year of Publication
2019
Topic
Fire
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Muszynski, Lech
Gupta, Rakesh
Hong, Seung Hyun
Osborn, Neil
Pickett, Brent
Organization
Oregon State University
Publisher
Elsevier
Year of Publication
2019
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Fire
Mechanical Properties
Keywords
Fire Resistance
Char Rate
PUR
MF
Deflection
Half-lap Joints
Research Status
Complete
Series
Fire Safety Journal
Summary
Fire concerns are one reason for building code restrictions against tall wood buildings in US. Despite growing body of empirical data on fire performance of cross-laminated timber (CLT) generated in Europe and Canada, lack of full-scale tests performed on structural CLT “made in the USA” is often quoted as a barrier for approval of massive timber in tall buildings in the US. The goal of this project was to contribute towards removing this barrier by testing the fire resistance of three full-scale unprotected CLT floor assemblies fabricated by two US-based manufacturers. The assemblies represented two species groups (SPF and DF-L), and two adhesive systems (PUR and MF). All assemblies met ASTM E119 standard qualifying criteria for 2-h fire rating in loaded condition. While char fall-off was observed in assemblies bonded with PUR, the differences in mean char rates in the first two layers between assemblies bonded with PUR and MF were smaller than the variability of char rates within individual assemblies. Statistical significant difference was observed only for cumulative char rate for the entire time of exposure. The effect of softening of the PUR bonds was most apparent as an accelerated rate of assembly deflection in the late stage of the tests. The unprotected half-lap joints provided adequate barrier against transmission of hot gases and flames through the assemblies.
Online Access
Free
Resource Link
https://pdf.sciencedirectassets.com/271100/1-s2.0-S0379711219X00053/1-s2.0-S0379711218305885/am.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEEMaCXVzLWVhc3QtMSJGMEQCIDPx6%2F0r%2FHVTQJ4dIafRmA3HwlGbcfNxmDLq4jjyvK3PAiAvLftbzlZ61shIRB1efaHazFSh9c7RiPv1sgh7xLTUkCrSBAg8EAQaDDA1OTAwMzU0Njg2NSIME%2FogFVutVaM1DKzrKq8E3uKFIQ9lxfiR4tIQ5oR4oSiJ%2FTsQyw%2FTFJstsBD%2B2w5XLorMtiaW6mqXhnzwAcbKDtFkNRarELjS6mmRBo1HiDi68YSGh1Pn2D5URF0NgNLbDFsnpeuc3FM4tHTubHCD4VJFhPlfixAF21w%2FWNhTlT0Izd4oFwm%2BMN9zcWsclrG6GccTlU4yqtflLe1R%2B7iQRWM1t9KXtZpld8Sb9sMvX9skbqmoehxyUGqqOPdY4%2FGr%2FUckZJafosr9rlSGdGAqsdNPWRxz9WuzgCjNCjFwccnbr%2FzfvCm4qLMyRK1LmjdqgsqbGYEXnXZSVZitVFDpygxH%2F7rF3lRO65TXT7U27p2RAbvq%2FUb6JBW%2BTRkICDC7T6DksT%2BGgmVjPcTxyWahOcFjA5wem5RnvPrO%2FvPZqt3TMiN9MrwGyN5aiXL5cFt8hLco2wLso0c9wrm6pGsF4r1wfcREPuGuGOky8O1xyxyJh07smHCXImM5BaUS%2FHoy0GSOyEyP8HgDiAeD3LCLFFl6jLGpW9REj3tUkQaN2dBKPhPyitcSCmStXGyw3HisA%2F1aC9joR8lCSuuSM7gXNF18d97w2b1RGPU5dKvY%2FXvWP%2FY%2BGexTVmo9%2FxU5ii1dgtJzEViCXtg7%2FRnMuWq8NJrl84Y9WzG5W8mGMwZeMqw4GH236S%2BPpusTJ6TBZCdmm1qc4yOlAbXpy3kLHqD10zTkEHHbY44tfXr%2FleDRvuft0NUZiQFai0zUjckCwDDXrNuUBjqqATje7b1UchMlqDY%2F0x32ozrkox7WAFjOK%2BnH4oFQzaQKm%2FAZpIPh3GLpHYv5Ar6y0vJnUl%2FpoD3T5ZeNWZLivqXvPR5YJc9v9FLDE4oJn5gIaXqdoLyijUrJjDHLK99ok3QMkZxnvWNRHY0kXMaqOiuz2oDax5bRtxV9GIDvoN3BRn48vEclfQtJCJSFwOUy7S5eICMvO5F%2Bk%2F1QNd3GzIBV%2FO79ewELWEwS&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20220601T040307Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTYSIV3POZV%2F20220601%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=cc99b0b1ab9587019cd039987a2619c82e0f19e5f58e3533b299b76cad3e29e3&hash=8aee703f3fc30b828ed3bc96daec8c857192c5cd8483a68ea7c0e1cb7eeb9cac&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S0379711218305885&tid=pdf-b0978c1f-5546-4c90-8925-a0dfc682b29c&sid=452576e25704d342c82a45827aafe4c69ff8gxrqa&type=client
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Hysteretic Behaviour of Metal Connectors for Hybrid (High- and Low-Grade Mixed Species) Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1659
Year of Publication
2016
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Mahdavifar, Vahid
Barbosa, André
Sinha, Arijit
Muszynski, Lech
Gupta, Rakesh
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Mechanical Properties
Connections
Keywords
Cyclic Loading
Wall-to-Floor
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3591-3598
Summary
Cross-laminated timber (CLT) is a prefabricated solid engineered wood product made of at least three orthogonally bonded layers of solid-sawn lumber that are laminated by gluing longitudinal and transverse layers with structural adhesives to form a solid panel. Previous studies have shown that the CLT buildings can perform well in seismic loading and are recognized as the essential role of connector performance in structural design, modelling, and analysis of CLT buildings. When CLT is composed of high-grade/high-density layers for the outer lamellas and low-grade/lowdensity for the core of the panels, the CLT panels are herein designated as hybrid CLT panels as opposed to conventional CLT panels that are built using one lumber type for both outer and core lamellas. This paper presents results of a testing program developed to estimate the cyclic performance of CLT connectors applied on hybrid CLT layups. Two connectors are selected, which can be used in wall-to-floor connections. These are readily available in the North American market. Characterization of the performance of connectors is done in two perpendicular directions under a modified CUREE cyclic loading protocol. Depending on the mode of failure, in some cases, testing results indicate that when the nails or screws penetrate the low-grade/low-density core lumber, a statistically significant difference is obtained between hybrid and conventional layups. However, in other cases, due to damage in the face layer or in the connection, force-displacement results for conventional and hybrid CLT layups were not statistically significant.
Online Access
Free
Resource Link
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