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8 records – page 1 of 1.

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.
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Fire Resistance Characteristics of Glued Laminated Timber Manufactured from Malaysian Tropical Hardwood Timber (Malagangai): Charring Rate and Fire Classification

https://research.thinkwood.com/en/permalink/catalogue1708
Year of Publication
2016
Topic
Fire
Material
Glulam (Glue-Laminated Timber)
Author
Ahmad, Zakiah
Aicher, Simon
Bakri, Zulhazmee
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Keywords
Charring Rate
Malagangai
Flame Spread
Smoke Production
Burning Droplets
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4471-4476
Summary
This paper reports the investigation on the one-dimensional charring rate of glued laminated timber manufactured from Malaysian Tropical Hardwood namely Malagangai (density, 800 kg/m 3 ). The fire test was conducted at SP Wood Technology in Stockholm in accordance with EN 13381-7:2014 for determination of charring rate. The reaction-to-fire tests for fire classifications in terms of flame spread, smoke production and burning droplets were investigated at University of Stuttgart, Germany in accordance with the procedures given in EN 13 501-1 : 2010. The results show that the charring rate of glulam Malagangai is 0.6 mm/min. The fire behaviour of the glulam is in Class C with medium smoke generation and very little burning droplets.
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Hardwood Glulams - Emerging Timber Products of Superior Mechanical Properties

https://research.thinkwood.com/en/permalink/catalogue523
Year of Publication
2014
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Aicher, Simon
Christian, Zachary
Dill-Langer, Gerhard
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Europe
Germany
Strength
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The paper reports on the recent state of hardwood glulams technically approved in Europe and/or Germany for load bearing structures. Build-ups, mechanical properties, manufacturing specifics and issues related to strength equations including size effects are discussed. The high potential of this emerging structural timber product group is herein also revealed. The driving forces for an increased attention in Europe towards glued laminated products made of hardwoods stems from several facts, the most important being: i) noticeable shortage and rapidly rising costs for softwoods, ii) high stocks of structurally so far not used hardwood resources in Central and Southern Europe and iii) a continuous shift in re-afforestation policies towards hardwoods due to better aptness of several broadleaf species versus soil and climate conditions.
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Holes in Glulam – Orientation and Design of Internal Reinforcements

https://research.thinkwood.com/en/permalink/catalogue1704
Year of Publication
2016
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Author
Tapia, Cristóbal
Aicher, Simon
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Holes
Steel Rods
Reinforcement
Tensile Stresses
Shear Stresses
Eurocode 5
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4404-4411
Summary
The usage of holes in glulam and LVL beams is a common practice in timber constructions and requires in many cases the application of reinforcement. At present, Eurocode 5 does not contain design rules for holes, nor for their reinforcement, which are, however, regulated in the German National Annex to EC5. Although it has been proven that internal rod-like reinforcements improve the shear force capacity of a beam with holes, several problems still remain, particularly the inability to successfully reduce peak stresses at the periphery of the hole, especially shear stresses. Inclined internal steel rod reinforcements were studied and compared with vertically oriented rods, which is currently the only regulated application. The analysis revealed a reduction of both perpendicular to grain tensile stresses and shear stresses, which for the case of vertical rods are not reduced at all. A first attempt at the design of such inclined reinforcements was made by deriving an equation based on the results from FEM simulations. The design approach was then applied to an example case. Experimental verification of the theoretical observations is still necessary and ongoing, though a very promising approach for an improved internal reinforcement and its respective design can already be observed.
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Hybrid Beech and Spruce Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1547
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Aicher, Simon
Hirsch, Maren
Christian, Zachary
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Beech
Rolling Shear Modulus
Rolling Shear Strength
Shear Tests
Compression Shear
Bending Tests
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1147-1155
Summary
The presented work examines the rolling shear properties of beech wood for the novel application as cross-layers in hybrid cross-laminated timber. Rolling shear modulus and strength of beech were determined by three different approaches: i) two-plate shear tests on single beech board slabs, and ii) compression shear and iii) bending tests on hybrid CLT specimens based on the test methods defined in EN 16351. The CLT specimens were cut from two industrially manufactured hybrid three-layered CLT-plates with a beech cross-layer and spruce outer layers. The rolling shear modulus results obtained from the single board tests and the bending tests agreed well and were within the range of 350 - 370 N/mm². The characteristic rolling shear strength obtained from the bending tests was determined as 2.6 N/mm², where the failure was often governed by longitudinal shearing of the spruce laminations. Hybrid CLT-plates demonstrate a highly improved strength and deflection behaviour versus homogenous spruce CLT-plates and result in not only a mechanically superior product but also allow for a greatly simplified design approach.
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Hybrid Cross Laminated Timber Plates (HCLTP) – Numerical Optimisation Modelling and Experimental Tests

https://research.thinkwood.com/en/permalink/catalogue1751
Year of Publication
2016
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Sustersic, Iztok
Brank, Boštjan
Dujic, Bruno
Brezocnik, Jaka
Gavric, Igor
Aicher, Simon
Dill-Langer, Gerhard
Winter, Wolfgang
Fadai, Alireza
Demschner, Thomas
Ledinek, Gregor
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Mechanical Properties
Keywords
Timber Ribs
Concrete Topping
Ultimate Limit States
Serviceability Limit States
Numerical Modelling
Experimental Tests
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4989-4996
Summary
This paper presents the development of two new types of hybrid cross-laminated timber plates (HCLTP) with an aim to improve structural performance of existing cross-laminated timber plates (Xlam or CLT). The first type are Xlam plates with glued timber ribs and the second type are Xlam plates with a concrete topping. A numerical...
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Novel Internally LVL-Reinforced Glued Laminated Timber Beams with Large Holes

https://research.thinkwood.com/en/permalink/catalogue1303
Year of Publication
2018
Topic
Design and Systems
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Aicher, Simon
Tapia, Cristóbal
Publisher
ScienceDirect
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Holes
Reinforcement
Beech
Load Capacity
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
A novel timber composite is presented, consisting of glued laminated timber (GLT) from softwoods and intercalated cross-layered plates of laminated veneer lumber (LVL) made of hardwood species, specifically beech. The structure is especially suited for beams with multiple, large rectangular holes, where the LVL acts as a highly efficient internal reinforcement and contributes to a damage-tolerant ultimate load behavior. The load capacity of the composite beam is not induced by the stress concentrations at the corners of the hole, which, in contrast to generic GLT, lead to a sudden propagation of cracks and brittle failure. It is shown that the structure, including the holes, can be designed analytically in a transparent manner by using beam theory, a parallel system approach, and modifications from FEM analysis for the verification of tensile forces at the hole periphery. The composite, firstly used in a recent multi-story building in Australia, significantly improves the competitiveness of timber in building works, which have been limited to steel and reinforced concrete structures.
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A Novel LVL- Based Internal Reinforcement for Holes in Glulam Beams

https://research.thinkwood.com/en/permalink/catalogue1908
Year of Publication
2018
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Tapia, Cristóbal
Aicher, Simon
Year of Publication
2018
Country of Publication
Korea
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Mechanical Properties
Keywords
Hybrid Build Up
Parametric Study
Finite Element Method (FEM)
Reinforcement
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 20-23,2018. Seoul, Republic of Korea
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8 records – page 1 of 1.