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Fire Tests on Finger-Jointed Timber Boards

https://research.thinkwood.com/en/permalink/catalogue170
Year of Publication
2014
Topic
Fire
Material
Glulam (Glue-Laminated Timber)
Author
Klippel, Michael
Frangi, Andrea
Organization
ETH Zurich
Year of Publication
2014
Format
Report
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Keywords
Adhesives
Strength
Finger-joint
Temperature
Fire Resistance
Research Status
Complete
Summary
This testing report summarises the experimental investigations on finger-jointed timber speci- mens, glued with different types of adhesives, loaded in tension and exposed to standard ISO-fire. The tests were performed as part of the project entitled “Fire safety of bonded structural timber elements” in the frame of a CTI-project (Commission for Technology and Innovation). The extensive testing programme on finger-jointed timber specimens was performed in cooperation with industry partners at the Swiss Federal Institute of Technology Zurich (ETH Zurich). The main aim of this research project is to clarify if the currently used design model for the fire re- sistance of bonded structural timber elements, such as glued-laminated timber, should consider the behaviour of adhesives at elevated temperatures. In this experimental study, different adhesives available on the market from adhesive man- ufacturer from Europe (such as Casco AG, Dynea AG, Jowat AG, Türmerleim AG, Purbond AG) were tested. Adhesives being used for structural applications as well as adhesives not certified according to current European testing standards for the use in structural applications were tested. The fire performance of 12 different adhesives - of type 1C PUR, MUF, PRF, EPI, PVAc, UF - were tested in a finger-jointed connection for cross-sections with a width of 80, 140 and 200 mm. In total, 49 fire tests were performed under ISO-fire exposure at the Swiss Federal Labora- tories for Materials Testing and Research (EMPA) in Duebendorf/ Switzerland. Two tests were conducted with specimens equipped with thermocouples to determine the temperature distribu- tion along the cross-section width. In the other tests, different parameters and their influence on the fire resistance were varied, such as the adhesive in the finger joint, the width of the specimen, the load level and the type of fire exposure on the testing lamella. The tests were performed in two test series in March and April, 2011 as well as in July and August, 2012. The second test series was extended by five additional tests with higher graded timber in August 2013. The main result from the first test series can be concluded as follows: The adhesives tested (2 x PUR, 1 x MUF) fulfil current approval criteria according to EN 301 (2013c) and EN 15425 (2008) for the use in load-bearing timber components in Europe. The adhesives fulfil at least the A7 test at 70 ° C according to EN 302-1 (2013a). Taking into account the failure pattern, no significant difference was observed between these adhesives. It could be shown that the higher loss of strength for some adhesives tested at elevated temperature does not necessarily lead to the same loss of strength in fire, since defects like knots may be dominant - depending on the strength class (grading). The main result from the second test series can be concluded as follows: No substantial difference was obtained for finger-jointed specimens glued with PRF and other structural ad- hesives. The PUR adhesive fulfilling the ASTM D7247 (2007) standard test at temperatures higher than 200 C did not reach a higher fire resistance than PUR adhesives which do not fulfil this standard. It was found that adhesives, which are used in structural timber members such as glued-laminated timber beams, need sufficient strength at lower temperatures than 200 C. iv This is especially explained by the steep temperature gradient typical for timber members such as glued-laminated timber. In addition to the fire tests, about 120 tensile tests on finger-jointed lamellas were performed at normal temperature. These lamellas were produced with the same types of adhesives as studied in the fire tests. The results of the whole investigation are summarised in this test report
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Investigation Concerning Life Cycle Assessment of Worked Timber: Japanese Larch Glued Laminated Timber of Eastern Nagano Prefecture

https://research.thinkwood.com/en/permalink/catalogue961
Year of Publication
June 2014
Topic
Environmental Impact
Material
Glulam (Glue-Laminated Timber)
Author
Matsukata, Keisuke
Asano, Yoshiharu
Takamura, Hideki
Hayakawa, Yoshiro
Publisher
J-STAGE
Year of Publication
June 2014
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Environmental Impact
Keywords
Life-Cycle Assessment
Larch
Carbon
Finger joint
Research Status
Complete
Series
Japan Architectural Institute Technical Report
Summary
In a process before being finished in a sawing factory after felled in forest, we clarified the actual situation of the carbon income and expenditure with edge materials and the fuel, and calculated the carbon balance of the house made by Nagano’s local wood. In this report, we carried out the actual survey and a hearing investigation in the laminated lumber factory and, calculated carbon balance of Japanese larch finger joint wood and glued laminated timber of eastern Nagano prefecture.
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Free
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Laminated Veneer Lumber Hollow Cross-sections for Temporary Soil Nailing

https://research.thinkwood.com/en/permalink/catalogue2486
Year of Publication
2019
Topic
Design and Systems
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems

Shear Resistance and Failure Modes of Edgewise Multiple Tab-and-Slot Joint (MTSJ) Connection with Dovetail Design for Thin LVL Spruce Plywood Kerto-Q Panels

https://research.thinkwood.com/en/permalink/catalogue1563
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Dedijer, Mira
Roche, Stéphane
Weinand, Yves
Year of Publication
2016
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Geometry
Multiple Tab-and-Slot Joints
Shear Test
Finger Joint
Failure Modes
Shear Strength
Shear Stiffness
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1548-1555
Summary
The objective of this study is to experimentally analyse effects of geometry variations of Multiple Tab and Slot Joint (MTSJ) connection with dovetail design on shear mechanical behaviour. Direct shear test was performed on angular ( = 90° ) MTSJ connection made of Kerto-Q 21mm-thick spruce plywood laminated veneer lumber (LVL) panels. Connection was examined in its configuration of three tabs/slots per edge. Nine different geometries of MTSJ connection were tested. In order to provide better understanding of mechanical behaviour of the connection, results were compared with finger joint (F) connection. Two characteristic failure modes were observed. Influence of three theta angles which define geometry of MTSJ connection was analysed concerning shear strength and stiffness. Connection showed very ductile shear behaviour with relatively high stiffness. It has been shown that by increasing q 3 angle above 30°, shear strength decreases. On the other hand, the highest influence on shear stiffness is due to q 2 and q 3 rotations.
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