DIN EN 408:2010-12

This European Standard specifies test methods for determining the following properties of structural timber and glued laminated timber: modulus of elasticity in bending, shear modulus, bending strength, modulus of elasticity in tension parallel to the grain, tension strength parallel to the grain, modulus of elasticity in compression parallel to the grain, compression strength parallel to the grain, modulus of elasticity in tension perpendicular to the grain, tension strength perpendicular to the grain, modulus of elasticity in compression perpendicular to the grain, compression strength perpendicular to the grain and shear strength. In addition, the determination of dimensions, moisture content of the timber, and density are specified. The methods apply to rectangular and circular shapes (of substantially constant cross section) of solid unjointed timber or finger-jointed timber and glued laminated timber unless stated otherwise. This 2010 revision replaces the previous test for the determination of the shear strength parallel to the grain by a new test method. The revised edition of 2003 added a global bending modulus of elasticity. The existing test has been renamed "determination of the local modulus of elasticity". Methods for determination of shear strength and mechanical properties perpendicular to the grain have also been added. These test methods were previously given in EN 1193, which has been withdrawn. The values obtained in any determination of the properties of timber depend upon the test methods used. It is therefore desirable that these methods be standardized so that results from different test centres can be correlated. Moreover, with the adoption of limit state design and with the development of both visual and machine stress grading, attention will be increasingly centred on the determination and monitoring of the strength properties and variability of timber in structural sizes. Again, this can be more effectively undertaken if the basic data are defined and obtained under the same conditions. This European Standard, which is based originally on ISO 8375, specifies laboratory methods for the determination of some physical and mechanical properties of timber in structural sizes. The methods are not intended for the grading of timber or for quality control. For the determination of shear modulus, alternative methods have been specified. The choice of which to use will depend upon the objective of the investigation and, to some extent, on the equipment available. Following testing to this standard it is intended that the determination of characteristic values will normally be obtained according to procedures specified in other European Standards. Attention is drawn to the advantages that may be gained, often with little extra effort, in extending the usefulness of test results by recording additional information on the growth characteristics of the pieces that are tested, particularly at the fracture sections. Generally, such additional information should include grade determining features such as knots, slope of grain, rate of growth, wane, and so on, on which visual grading rules are based, and strength indicating parameters such as localized modulus of elasticity, on which some machine stress grading is based. This document (EN 408:2010) has been prepared by Technical Committee CEN/TC 124 "Timber structures", the secretariat of which is held by AFNOR (France). The responsible German Committee is Working Committee NA 005-04-01 AA "Holzbau" ("Spiegelausschuss von CEN/TC 124, CEN/TC 250/SC 5") ("Timber structures (Mirror Committee of CEN/TC 124, CEN/TC 250/SC 5)") of the Building and Civil Engineering Standards Committee at DIN, the German Institute for Standardization e. V. Amendments The following amendments have been made with respect to DIN EN 408:2004-08: a) test method for determining the shear strength has been replaced by a new method; b) various symbols and abbreviations have been added; c) specifications for other permitted methods for the determination of global modulus of elasticity have been added in 10.2; d) text has been added and a note has been incorporated; e) clause 11 has been revised, more figures have been incorporated in 10.3; f) clause 19 has been revised; g) figures, formulas and clauses have been renumbered.