Untersuchung von Buchenschnittholz (Fagus sylvatica L.) hinsichtlich der Eignung für Brettschichtholz

Abstract

Beech glulam for structural purposes has to be manufactured from strength graded beech lumber. At present one can assume that such material is not available on the market: There is not only a lack of practice in strength grading of beech lumber but also a lack of clearly defined raw material to be strength graded for beech glulam. This article aims to show that beech lumber graded following the Rules of the Measurement and Inspection of Hardwood and Cypress (published by the National Hardwood Lumber Association) has a potential as raw material for beech glulam. 218 beech boards approximately complying with two different grades, an upper and a common grade, were examined in regard to visual strength grading according to DIN 4074-5 (2003). The results show that 90% of the upper grade and 50% of the common grade boards fulfil the requirements for grade LS10 in DIN 4074-5 (2003). This finally enables the manufacture of beech glulam in accordance with strength class GL28. In addition, mechanical strength grading taking into account the modulus of elasticity even enables grading of 80% of the upper and 40% of the common grade boards for GL40.