Glued laminated timber. Large finger joints. Performance requirements and minimum production requirements

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.

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Proof-Loaded Finger-Joints for Structural Glued Laminated Timber

Production, Marketing and Use of Finger-Jointed Sawnwood - Forestry Sciences ◽

10.1007/978-94-015-3859-6_14 ◽

1982 ◽

pp. 115-120

Author(s):

E. Robert ◽

P. E. Eby

Keyword(s):

Finger Joints ◽

Glued Laminated Timber

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EUCALYPTUS SPP. GLUED LAMINATED TIMBER WITH REINFORCED FIBER FINGER-JOINTS

FLORESTA ◽

10.5380/rf.v51i1.67392 ◽

2020 ◽

Vol 51 (1) ◽

pp. 109

Author(s):

Cleide Beatriz Bourscheid ◽

Rodrigo Figueiredo Terezo

Keyword(s):

Finger Joints ◽

Glued Laminated Timber ◽

Reinforced Fiber

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Glued laminated timber. Performance requirements and minimum production requirements

10.3403/02524658 ◽

2002 ◽

Cited By ~ 3

Keyword(s):

Performance Requirements ◽

Glued Laminated Timber

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STRENGTH OF STRUCTURAL FINGER-JOINTS REINFORCED WITH FIBERS

FLORESTA ◽

10.5380/rf.v49i1.53549 ◽

2018 ◽

Vol 49 (1) ◽

pp. 031

Author(s):

Cleide Beatriz Bourscheid ◽

Rodrigo Figueiredo Terezo ◽

Polliana D’Angelo Rios ◽

Alexsandro Bayestroff Da Cunha ◽

Deyvis Borges Waltrick ◽

...

Keyword(s):

Tensile Strength ◽

Pinus Taeda ◽

Carbon Fibers ◽

Solid Wood ◽

Mechanical Resistance ◽

Finger Joints ◽

Number Of Layers ◽

Glued Laminated Timber ◽

Dunnett Test ◽

Structural Adhesive

The finger-joints are the kind of top joints most used in wood blades to manufacture glued laminated timber (GLULAM) and present direct influence on their rigidity and final mechanical strength. Thus, the objective of this study was to evaluate the tensile strength parallel to grain with different compositions of reinforcements concentrated on finger-joints. Two geometries were used to execute the finger-joints and two species: Pinus taeda and Eucalyptus spp. The reinforcements were fabrics from glass or carbon fibers bonded with polyurethane structural adhesive. The treatments used were: "A-Glass", "A-Glass2", "A-Carbon", “A-Without reinforcement”, "B-Glass", "B-Glass2", "B-Carbon" and “B-Without reinforcement”, being "A" or "B", the geometries and "2", the number of layers of tissue. For statistical analysis, the Dunnett test was used at 95% confidence interval. The results showed that the execution of the unreinforced finger-joints decreased the tensile strength of the woods. For P. taeda, all the treatments were significantly inferior to the control (without finger-joints), and for Eucalyptus spp., only the treatment "A-Unreinforced" presented inferior performance to the control (without finger-joints), all others presented equivalent mechanical resistance to solid wood. It can be concluded that for the Eucalyptus spp. wood, the application of reinforcement on the structural finger-joints improves the tensile strength, equating to the solid wood.

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