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Analysis of Economic Feasibility of Ash and Maple Lamella Production for Glued Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2225
Year of Publication
2019
Topic
Cost
Material
Glulam (Glue-Laminated Timber)
Author
Schlotzhauer, Philipp
Kovryga, Andriy
Emmerich, Lukas
Bollmus, Susanne
Van de Kuilen, Jan-Willem
Militz, Holger
Publisher
MDPI
Year of Publication
2019
Country of Publication
Switzerland
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Cost
Keywords
Europe
Maple
Ash
Strength
Hardwood
Language
English
Research Status
Complete
Series
Forests
ISSN
1999-4907
Online Access
Free
Resource Link
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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
Country of Publication
Germany
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
Language
English
Research Status
Complete
Series
European Journal of Wood and Wood Products
ISSN
1436-736X
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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Investigation of a Post-Tensioned Timber Connection

https://research.thinkwood.com/en/permalink/catalogue335
Year of Publication
2014
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Frangi, Andrea
Wanninger, Flavio
Organization
ETH Zurich
Year of Publication
2014
Country of Publication
Switzerland
Format
Report
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Ash
Bending Test
Failure
Hardwood
Post-Tensioned
Reinforcement
Spruce
Language
English
Research Status
Complete
Summary
A post tensioned timber connection made of glulam has been developed at the ETH in Zurich. The connection is made of spruce with ash reinforcement in the connection area where high stresses perpendicular to the grain occur. The moment-rotation-behaviour of this post-tensioned beam-column timber joint has been analysed with a series of static bending tests. The timber joint was loaded at the ends of the beams in order to apply a moment to the connection. The tests were conducted with different forces in the tendon, from 300 kN up to 700 kN. The bending tests were performed with a controlled load level, so that no embedment failure perpendicular to the grain occurred in the column. The intended self-centring behaviour could be verified and no damage could be observed during all the tests. A final bending test was conducted in order to study the failure mode of the post-tensioned timber connection. The vertical load on the beams was increased until the tendon-elongation got so high that the test had to be aborted due to safety reasons. Nearly no damage occurred during the last test, only minor residual deformations could be observed. The failure is an embedment failure in the column due to exceedance of the strength perpendicular to the grain. The specimen, test setup, instrumentation and the results of all performed tests are presented in this technical report.
Online Access
Free
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Investigation of the Bond Quality of Semi Industrially Produced Ash Glulam

https://research.thinkwood.com/en/permalink/catalogue1524
Year of Publication
2016
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Lehmann, Martin
Schlegel, Sven
Ammann, Samuel
Beyer, Mario
Aehlig, Karsten
Jung, Heiko
Niemz, Peter
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Ash
Delamination Test
Tensile Shear Strength
Adhesives
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 648-653
Summary
Delamination resistance and tensile shear strength (TSS) are essential for structural adhesives used in timber industry. Thus these two factors were investigated on bonded ash (Fraxinus excelsior L.) to check the suitability of adhesively bonded ash as building material. For determination of the delamination resistance industrially bonded ash glulam was used. The specimens for the tensile shear tests where produced in the laboratory. Four different adhesives types and different pre-treatment were investigated. The samples for TSS were tested in dry and wet condition. 80% of the tested series met the requirements of the standards at dry, and only 30% passed at wet condition. None of the adhesives tested was able to pass the delamination test. No distinct influence of the different parameters studied is notable for most of the adhesive systems, only extended closed assembly time and lower mixing ratios seem to improve the bond quality of MUF. Additional chemical analyses, conducted to find evidence for the poor bonding performance, showed that fatty acid content, pH and acidic extractives are in between the range of beech (Fagus sylvatica L.) and Spruce (Picea abies Karst.). However the formic acid is an exception with a four times higher amount as the other two species investigated.
Online Access
Free
Resource Link
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Rolling Shear Properties of Some European Timber Species with Focus on Cross Laminated Timber (CLT): Test Configuration and Parameter Study

https://research.thinkwood.com/en/permalink/catalogue25
Year of Publication
2015
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Frangi, Andrea
Schickhofer, Gerhard
Brandner, Reinhard
Ehrhart, Thomas
Organization
International Network on Timber Engineering Research (INTER)
Year of Publication
2015
Country of Publication
Croatia
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Failure
Rolling shear
Testing
Norway Spruce
Pine
Birch
Beech
Poplar
Ash
Language
English
Conference
INTER 2015
Research Status
Complete
Notes
August 24-27, 2015, Šibenik, Croatia
Summary
Cross laminated timber (CLT) has gained popularity and relevance in the construction industry during the past decade. Its versatile applicability, economic competitiveness as well as an increasing social consciousness for sustainable constructions have been main reasons for this positive development. Its laminar composition enables CLT to withstand in- and out-of-plane loads. Due to its structure featuring orthogonally oriented adjacent layers, in CLT loaded out-of-plane, shear and more specific rolling shear has to be considered in ultimate (ULS) as well as serviceability limit state (SLS) design. This is because rolling shear constitutes a potential failure mechanism and contributes a noticeable amount to the overall deflection. Comprehensive knowledge on rolling shear modulus (GR) and strength (fR) is therefore of utmost importance for an adequate design of CLT structures. Previous investigations on rolling shear properties and their influential parameters have primarily been performed numerically and using Norway spruce (Picea abies). The main goal of our contribution, based on investigations detailed in Ehrhart (2014), was to identify the most important parameters for rolling shear characteristics and to quantify their influence. Furthermore, information about the rolling shear performance of several timber species was analysed to investigate their potential for use in CLT-products. In view of upcoming new timber species increasingly pushed into the market, investigations on rolling shear comprised also some hardwood and other softwood species with a potential to be used for (cross) laminated timber products.
Online Access
Free
Resource Link
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