European beech (Fagus sylvatica L.) glued laminated timber: lamination strength grading, production and mechanical properties

Ehrhart, Thomas; Steiger, René; Lehmann, Martin; Frangi, Andrea (2020). European beech (Fagus sylvatica L.) glued laminated timber: lamination strength grading, production and mechanical properties European Journal of Wood and Wood Products, 78(5), pp. 971-984. 10.1007/s00107-020-01545-6

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This paper presents the results of extensive investigations on the lamination strength grading, the production and the mechanical properties of European beech (Fagus sylvatica L.) glued laminated timber (GLT). Based on the analysis of potential influencing parameters on strength and stiffness as well as subsequent tension tests parallel to the grain on single boards, a combined visual/machine approach for grading the raw material into tensile strength classes T50, T42, T33 and T22 was developed. Boards strength graded with the developed procedure were then finger-jointed by a Swiss GLT producer and the strength of the finger joints was investigated by means of tension and bending tests. The strength and durability of the bonding was investigated and verified by means of tensile-shear and delamination tests. It could be shown that the required finger-joint and bondline strengths for GLT of strength classes GL40 and GL48 can be achieved, but that the process parameters for finger jointing (in particular the geometrical properties of the finger joint profile) have to be optimized in order to be able to produce GLT of strength class GL55. Finally, an extensive experimental testing campaign was performed to investigate the mechanical properties of European beech GLT produced based on the strength grading rules and production techniques developed before. Bending, tensile and compressive parallel to the grain, as well as shear tests were carried out on GLT specimens of strength classes GL40, GL48 and GL55 in different sizes in terms of cross-section and length. Based on these investigations and complementing numerical simulations, characteristic strength and stiffness values and formulae for consideration of size effects in bending, tension and shear were determined.

Item Type:	Journal Article (Original Article)
Division/Institute:	School of Architecture, Wood and Civil Engineering School of Architecture, Wood and Civil Engineering > Institute for Materials and Wood Technology School of Architecture, Wood and Civil Engineering > Institute for Materials and Wood Technology > Adhesive Technology BFH Centres and strategic thematic fields > BFH Centre for Wood - Resource and Material School of Architecture, Wood and Civil Engineering > Institut for Building Materials and Biobased Products IBBM School of Architecture, Wood and Civil Engineering > Institut for Building Materials and Biobased Products IBBM > Wood Modification and Gluing Technology group FGHV
Name:	Ehrhart, Thomas; Steiger, René; Lehmann, Martin0000-0002-0813-7023 and Frangi, Andrea
Subjects:	T Technology > T Technology (General) T Technology > TA Engineering (General). Civil engineering (General) T Technology > TG Bridge engineering T Technology > TH Building construction T Technology > TP Chemical technology
ISSN:	0018-3768
Language:	English
Submitter:	Martin Lehmann
Date Deposited:	14 Dec 2020 11:46
Last Modified:	04 Nov 2022 11:14
Publisher DOI:	10.1007/s00107-020-01545-6
ARBOR DOI:	10.24451/arbor.13746
URI:	https://arbor.bfh.ch/id/eprint/13746