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Bondline Shear Strength and Wood Failure of European and Tropical Hardwood Glulams

https://research.thinkwood.com/en/permalink/catalogue1372
Year of Publication
2018
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Aicher, Simon
Ahmad, Zakiah
Hirsch, Maren
Publisher
Springer Berlin Heidelberg
Year of Publication
2018
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Keywords
Keruing
Melangangai
Light Red Meranti
Sweet Chestnut
Oak
Beech
Ash
Teak
Hardwood
Shear Strength
Bondlines
Adhesives
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
The study reports on block shear investigations with bondlines of face-glued laminations and matched solid wood specimens from hardwood glulam (GLT) beams produced industrially from eight technically and stand volume-wise important species. The European hardwoods comprised oak, beech, sweet chestnut and ash and the tropical species were teak, keruing, melangangai and light red meranti. The adhesives were phenol-resorcinol and melamine-urea. When combining all species in one sample, a rather strong linear relationship of bond and wood shear strength was observed. The ratio of bond vs. wood shear strength was for all species on the mean value level = 0.9, and likewise (with one exception) for the respective strengths’ 5%-quantiles. Consistent with literature, the test results showed no significant correlations between bond shear strength and density, wood shear strength and wood failure percentage of individual species, respectively. The investigations render the methodological basics of some international standards on bond quality verification as being inappropriate. New, empirically validated hardwood GLT bond requirements are proposed for discussion and implementation at the CEN and ISO levels. The strength ratio specifications reflect respective ANSI provisions, yet the reference quantity wood shear strength is now determined in an unbiased manner from matched GLT specimens. The wood failure verification proposal is based on the 10%-quantile and mean level for initial type testing and factory production control. The requirements further account for the pronounced difference observed in scatter of wood failure between European and tropical species.
Online Access
Free
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Variations of Moisture Content in Manufacturing CLT-Concrete Composite Slab Using Wet Construction Method

https://research.thinkwood.com/en/permalink/catalogue2732
Year of Publication
2021
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Song, Yo-Jin
Baek, Seong-Yeob
Lee, In-Hwan
Hong, Soon-Il
Publisher
North Carolina State University
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Moisture
Keywords
Wet Construction Method
Moisture Content
Teak
Composite
Adhesive
Delamination
Research Status
Complete
Series
BioResources
Summary
Construction of eco-friendly high-rise buildings using cross-laminated timber (CLT)-concrete composite (CCC) slabs is increasing. CLT and concrete, which are major component materials of the CCC slab, are significantly affected by moisture. In particular, the moisture content of concrete in the production process affects the quality of both materials. In this study, the effects of the wet construction method on CLT and concrete component materials are examined by monitoring the behavior of the CCC slab during curing time (28 d) and by evaluating the quality of the concrete and CLT after curing. When manufacturing the CCC using the wet construction method, moisture penetration from the concrete into the CLT during the curing time is suppressed by the shear bonding between the concrete and the CLT when an adhesive is used. This minimizes the effect of the moisture on both component materials, consequently yielding uniform compressive strength to the concrete after curing and preventing the deterioration of the CLT’s delamination performance. Therefore, the shear bonding method using an adhesive is expected to minimize the quality deterioration observed in concrete and CLT after curing.
Online Access
Free
Resource Link
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