SIST EN 408:2010
(Main)Timber Structures - Structural timber and glued laminated timber - Determination of some physical and mechanical properties
Timber Structures - Structural timber and glued laminated timber - Determination of some physical and mechanical properties
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, and density of test pieces 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.
Holzbauwerke - Bauholz für tragende Zwecke und Brettschichtholz - Bestimmung einiger physikalischer und mechanischer Eigenschaften
Diese Europäische Norm legt Prüfverfahren zur Bestimmung der folgenden Eigenschaften von Bauholz für tragende Zwecke und Brettschichtholz fest: Biege-Elastizitätsmodul, Schubmodul, Biegefestigkeit, Zug-Elasti-zitätsmodul in Faserrichtung, Zugfestigkeit in Faserrichtung, Druck-Elastizitätsmodul in Faserrichtung, Druck-festigkeit in Faserrichtung, Zug-Elastizitätsmodul rechtwinklig zur Faserrichtung, Zugfestigkeit rechtwinklig zur Faserrichtung, Druck-Elastizitätsmodul rechtwinklig zur Faserrichtung, Druckfestigkeit rechtwinklig zur Faser-richtung sowie die Scherfestigkeit. Zusätzlich wird die Bestimmung der Maße, der Holzfeuchte und der Rohdichte festgelegt. Sofern nicht anders angegeben, gelten die Verfahren für rechteckige und kreisförmige Formen (mit im Wesentlichen konstantem Querschnitt) aus ungestoßenem oder keilgezinktem Bauholz und Brettschichtholz.
Structures en bois - Bois de structure et bois lamellé-collé - Détermination de certaines propriétés physiques et mécaniques
La présente Norme européenne définit des méthodes d'essai pour déterminer les propriétés suivantes du bois de structure et du bois lamellé-collé : le module d'élasticité en flexion, le module de cisaillement, la résistance à la flexion, le module d'élasticité en traction axiale, la résistance à la traction axiale, le module d'élasticité en compression axiale, la résistance à la compression axiale, le module d'élasticité en traction transversale, la résistance à la traction transversale, le module d'élasticité en compression transversale, la résistance à la compression transversale et la résistance au cisaillement.
La détermination des dimensions, de la teneur en humidité et de la masse volumique des éprouvettes d'essai est également définie.
Sauf indication contraire, les méthodes s'appliquent aux bois massifs non aboutés ou aboutés par entures multiples et aux bois lamellés-collés de formes rectangulaire et circulaire (de section relativement constante).
Lesene konstrukcije - Konstrukcijski les in lepljeni lamelirani les - Ugotavljanje nekaterih fizikalnih in mehanskih lastnosti
Ta evropski standard določa preskusne metode za ugotavljanje naslednjih lastnosti strukturnega lesa in lameliranega lepljenega lesa: modul elastičnosti upogibanja; strižni modul; moč upogibanja; modul elastičnosti pri napetosti, vzporedni z vlakni; modul elastičnosti pri moči stiskanja, vzporedni z vlakni; modul elastičnosti pri napetosti navpično na vlakna; moč stiskanja navpično na vlakna; modul elastičnosti pri stiskanju navpično na vlakna; moč stiskanja navpično na vlakna in moč striženja. Poleg tega je opredeljeno določevanje dimenzij, vlage in gostote preskušancev. Metode veljajo za pravokotne in okrogle oblike (konstantnega prereza) trdnega nespajanega lesa ali lesa, spajanega z zobatimi spoji, ter lameliranega lepljenega lesa, razen če je navedeno drugače.
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Lesene konstrukcije - Konstrukcijski les in lepljeni lamelirani les - Ugotavljanje nekaterih fizikalnih in mehanskih lastnostiHolzbauwerke - Bauholz für tragende Zwecke und Brettschichtholz - Bestimmung einiger physikalischer und mechanischer EigenschaftenStructures en bois - Bois de structure et bois lamellé-collé - Détermination de certaines propriétés physiques et mécaniquesTimber Structures - Structural timber and glued laminated timber - Determination of some physical and mechanical properties91.080.20Lesene konstrukcijeTimber structures79.040Les, hlodovina in žagan lesWood, sawlogs and sawn timberICS:Ta slovenski standard je istoveten z:EN 408:2010SIST EN 408:2010en,fr,de01-november-2010SIST EN 408:2010SLOVENSKI
STANDARDSIST EN 408:20041DGRPHãþD
SIST EN 408:2010
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 408
August 2010 ICS 79.040; 79.060.99; 91.080.20 Supersedes EN 408:2003English Version
Timber structures - Structural timber and glued laminated timber - Determination of some physical and mechanical properties
Structures en bois - Bois de structure et bois lamellé-collé -Détermination de certaines propriétés physiques et mécaniques
Holzbauwerke - Bauholz für tragende Zwecke und Brettschichtholz - Bestimmung einiger physikalischer und mechanischer Eigenschaften This European Standard was approved by CEN on 9 July 2010.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 408:2010: ESIST EN 408:2010
EN 408:2010 (E) 2 Contents Page Foreword .4Introduction .51 Scope .62 Normative references .63 Terms and definitions .64 Symbols and abbreviations .65 Determination of dimensions of test pieces .86 Determination of moisture content of test pieces .87 Determination of density of test pieces .88 Conditioning of test pieces .89 Determination of local modulus of elasticity in bending .99.1 Test piece .99.2 Procedure .99.3 Expression of results . 1010 Determination of global modulus of elasticity in bending . 1110.1 Test piece . 1110.2 Procedure . 1110.3 Expression of results . 1211 Determination of the shear modulus . 1311.1 Torsion method . 1311.1.1 Test piece . 1311.1.2 Procedure . 1311.1.3 Expression of results . 1511.2 Shear field test method . 1611.2.1 Test piece . 1611.2.2 Procedure . 1611.2.3 Expression of results . 1812 Determination of modulus of elasticity in tension parallel to the grain . 1812.1 Test piece . 1812.2 Procedure . 1812.3 Expression of results . 1913 Determination of tension strength parallel to the grain. 1913.1 Test piece . 1913.2 Procedure . 2013.3 Expression of results . 2014 Determination of modulus of elasticity in compression parallel to the grain . 2014.1 Test piece . 2014.2 Procedure . 2114.3 Expression of results . 2115 Determination of compression strength parallel to grain . 2115.1 Test piece . 2115.2 Procedure . 2115.3 Expression of results . 2216 Determination of tension and compression strengths perpendicular to the grain . 2216.1 Requirements for test pieces . 22SIST EN 408:2010
EN 408:2010 (E) 3 16.1.1 Fabrication . 2216.1.2 Surface preparation . 2216.2 Procedure . 2316.3 Expression of results . 2516.3.1 Compression perpendicular to the grain . 2516.3.2 Tension perpendicular to the grain . 2517 Determination of modulus of elasticity perpendicular to the grain . 2517.1 Requirements for test pieces . 2517.2 Procedure . 2517.3 Expression of results . 2617.3.1 Compression perpendicular to the grain . 2617.3.2 Tension perpendicular to the grain . 2718 Determination of shear strength parallel to the grain . 2718.1 Requirements for test pieces . 2718.1.1 Fabrication . 2718.1.2 Surface preparation . 2718.2 Procedure . 2818.3 Expression of results . 2919 Bending strength parallel to grain . 3019.1 Test piece . 3019.2 Procedure . 3019.3 Expression of results . 3120 Test report . 3220.1 General . 3220.2 Test piece . 3220.3 Test method . 3220.4 Test results . 32Annex A
(informative)
Example of compression perpendicular to grain test arrangement . 33Annex B
(informative)
Example of tension perpendicular to grain test arrangement with rigid fixings . 35Bibliography . 36 SIST EN 408:2010
EN 408:2010 (E) 4 Foreword This document (EN 408:2010) has been prepared by Technical Committee CEN/TC 124 “Timber structures”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2011, and conflicting national standards shall be withdrawn at the latest by February 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 408:2003. In this revised standard a new test is added for the determination of the shear modulus. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 408:2010
EN 408:2010 (E) 5
Introduction This 2010 revision replaces the test for the determination of the shear strength parallel to grain. The revised edition of 2003 added a global bending modulus of elasticity, whilst renaming the existing test as the local modulus of elasticity. It also includes the methods for determination of shear strength and mechanical properties perpendicular to the grain, previously given in EN 1193, which has now 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, etc., 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. SIST EN 408:2010
EN 408:2010 (E) 6 1 Scope 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, and density of test pieces 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. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 13183-1, Moisture content of a piece of sawn timber
Part 1: Determination by oven dry method 3 Terms and definitions Not applicable. 4 Symbols and abbreviations A
cross-sectional area, in square millimetres; a
distance between a loading position and the nearest support in a bending test, in millimetres; b width of cross section in a bending test, or the smaller dimension of the cross section, in millimetres; Ec,0
modulus of elasticity in compression parallel to the grain, in newtons per square millimetre; Ec,90 modulus of elasticity in compression perpendicular to the grain, in newtons per square millimetre; Em,g
global modulus of elasticity in bending, in newtons per square millimetre; Em,l
local modulus of elasticity in bending, in newtons per square millimetre; Et,0
modulus of elasticity in tension parallel to the grain, in newtons per square millimetre; Et,90 modulus of elasticity in tension perpendicular to the grain, in newtons per square millimetre; F
load, in newtons; Fc,90 compressive load perpendicular to the grain, in newtons; Fc,90,max maximum compressive load perpendicular to the grain, in newtons; Fc,90,max,est estimated maximum compressive load perpendicular to the grain, in newtons; Fmax
maximum load, in newtons; SIST EN 408:2010
EN 408:2010 (E) 7 Fmax,est
estimated maximum load, in newtons; Ft,90 tensile load perpendicular to the grain, in newtons; Ft,90,max maximum tensile load perpendicular to the grain, in newtons; G shear modulus, in newtons per square millimetre; S first moment of area, in millimetres to the third power; fc,0
compressive strength parallel to the grain, in newtons per square millimetre; fc,90 compressive strength perpendicular to the grain, in newtons per square millimetre; fm
bending strength, in newtons per square millimetre; ft,0
tensile strength parallel to the grain, in newtons per square millimetre; ft,90 tensile strength perpendicular to the grain, in newtons per square millimetre; fv shear strength parallel to the grain, in newtons per square millimetre; fv,k characteristic shear strength parallel to the grain, in newtons per square millimetre; G
shear modulus, in newtons per square millimetre; Gtor,t
shear modulus in torsion, in newtons per square millimetre; Gtor,s shear modulus in shear field, in newtons per square millimetre;
h
depth of cross section in a bending test, or the larger dimension of the cross section, or the test piece height in perpendicular to grain and shear tests, in millimetres; h0 gauge length, in millimetres; I
second moment of area, in millimetres to the fourth power; K, k
coefficients; kG
coefficient for shear modulus; ktor torque stiffness, in newton metres per radian; ks shear stiffness; l
span in bending, or length of test piece between the testing machine grips in compression and tension, in millimetres; 1l
gauge length for the determination of modulus of elasticity or shear modulus, in millimetres; 2l distance between the supports and gauge length in torsion, in millimetres; t plate thickness, in millimetres; Tr torque, in newton millimetres; Vs shear force, in newtons; SIST EN 408:2010
EN 408:2010 (E) 8 W
section modulus, in millimetres to the third power; w
deformation or displacement, in millimetres; ϕ rotation, in radians; χ, η shape factors. Suffixes 1, 2
refer to loads or deformations or pieces at particular points of a test and are referred to as necessary in the text. 5 Determination of dimensions of test pieces The dimensions of the test piece shall be measured to an accuracy of 1 %. All measurements shall be made when the test pieces are conditioned as specified in Clause 8. If the width or thickness varies within a test piece, these dimensions should be recorded as the average of three separate measurements taken at different positions on the length of each piece. The measurements shall not be taken closer than 150 mm to the ends. Specimens for perpendicular to grain tests shall be planed. 6 Determination of moisture content of test pieces The moisture content of the test piece shall be determined in accordance with EN 13183-1 on a section taken from the test piece. For structural timber the section shall be of full cross section, free from knots and resin pockets. For perpendicular to grain test specimens the moisture content shall be determined from the whole specimen. In strength tests for bending and tension parallel to grain and compression parallel to grain, the section shall be cut as close as possible to the fracture. 7 Determination of density of test pieces The density of the whole cross section of the test piece shall be determined on a section taken from the test piece. For structural timber the section shall be of full cross section, free from knots and resin pockets. In strength tests, the section shall be cut as close as possible to the fracture. For perpendicular to grain test specimens the density of the test pieces shall be determined prior to test after conditioning from the measurements of mass and volume of the whole test piece. 8 Conditioning of test pieces All tests shall be carried out on pieces, which are conditioned at the standard environment of (20 ± 2) °C and (65 ± 5) % relative humidity. A test piece is conditioned when it attains constant mass. Constant mass is considered to be attained when the results of two successive weightings, carried out at an interval of 6 h, do not differ by more than 0,1 % of the mass of the test piece. Where the timber to be tested is not readily conditioned to the above standard environment (e.g. for hardwoods with high densities) that fact shall be reported. For small specimens, unless otherwise protected, test pieces shall not be removed from the conditioning environment more than 1 h before testing. SIST EN 408:2010
EN 408:2010 (E) 9 Test pieces can be stored in the test area for up to 24 h provided they are close piled and wrapped in vapour tight sheeting. 9 Determination of local modulus of elasticity in bending 9.1 Test piece The test piece shall have a minimum length of 19 times the depth of the section. Where this is not possible, the span of the beam shall be reported. 9.2 Procedure The test piece shall be symmetrically loaded in bending at two points over a span of 18 times the depth as shown in Figure 1. If the test piece and equipment do not permit these conditions to be achieved exactly, the distance between the load points and the supports may be changed by an amount not greater than 1,5 times the piece depth, and the span and test piece length may be changed by an amount not greater than three times the piece depth, while maintaining the symmetry of the test. The test piece shall be simply supported. Small steel plates of length not greater than one-half of the depth of the test piece may be inserted between the piece and the loading heads or supports to minimize local indentation. Lateral restraint shall be provided as necessary to prevent lateral torsional buckling. This restraint shall permit the piece to deflect without significant frictional resistance. Load shall be applied at a constant rate. The rate of movement of the loading head shall be not greater than (0,003 h) mm/s (see Figure 1). The maximum load applied shall not exceed 0,4 Fmax,est. The estimated maximum load, Fmax,est of the material under test shall be obtained either from tests on a least ten pieces of the appropriate species, size and grade or from appropriate existing test data.
Figure 1 — Test arrangement for measuring local modulus of elasticity in bending SIST EN 408:2010
EN 408:2010 (E) 10 The loading equipment used shall be capable of measuring the load to an accuracy of 1 % of the load applied to the test piece or, for loads less than 10 % of the applied maximum load, with an accuracy of 0,1 % of the maximum applied load. The deformation w shall be taken as the average of measurements on both side faces at the neutral axis, and shall be measured at the centre of a central gauge length of five times the depth of the section. The measuring equipment used shall be capable of measuring deformation to an accuracy of 1 % or, for deformations less than 2 mm, with an accuracy of 0,02 mm. 9.3 Expression of results Using data obtained from the local modulus of elasticity test, plot the load/deformation graph.
Use that section of the graph between 0,1 Fmax,est and 0,4 Fmax,est for a regression analysis. Find the longest portion of this section that gives a correlation coefficient of 0,99 or better. Provided that this portion covers at least the range 0,2 Fmax,est to 0,3 Fmax,est calculate the local modulus of elasticity from the following expression: ()()121221,16wwIFFalElm−−= (1) where F2 − F1
is an increment of load in newtons on the regression line with a correlation coefficient of 0,99 or better; and w2 − w1
is the increment of deformation in millimetres corresponding to F2 − F1 (see Figure 2). The local modulus of elasticity, Em,l shall be calculated to an accuracy of 1 %. If a portion of the graph cannot be found with a correlation coefficient of 0,99 or better covering the range 0,2 Fmax,est to 0,3 Fmax,est, check the test equipment and take measures to eradicate any errors caused by distorted specimens. If 0,99 is still not achieved, discard the specimen. The modulus of elasticity shall be calculated to an accuracy of 1 %. SIST EN 408:2010
EN 408:2010 (E) 11
Key F load w deformation Figure 2 — Load-deformation graph within the range of elastic deformation 10 Determination of global modulus of elasticity in bending 10.1 Test piece The test piece shall have a minimum length of 19 times the depth of the section. Where this is not possible, the span of the beam shall be reported. 10.2 Procedure The test piece shall be symmetrically loaded in bending at two points over a span of 18 times the depth as shown in Figure 3. If the test piece and equipment do not permit these conditions to be achieved exactly, the distance between the load points and the supports may be changed by an amount not greater than 1,5 times the piece depth, and the span and test piece length may be changed by an amount not greater than three times the piece depth, while maintaining the symmetry of the test. The test piece shall be simply supported. Small steel plates of length not greater than one-half of the depth of the test piece may be inserted between the piece and the loading heads or supports to minimize local indentation. Lateral restraint shall be provided as necessary to prevent lateral (torsional) buckling. This restraint shall permit the piece to deflect without significant frictional resistance. SIST EN 408:2010
EN 408:2010 (E) 12 Load shall be applied at a constant rate. The rate of movement of the loading head shall be not greater than (0,003 h) mm/s (see Figure 3).
The maximum load applied shall not exceed 0,4 Fmax,est or cause damage to the piece unless this test is carried out in conjunction with Clause 19. The estimated maximum load, Fmax,est of the material under test shall be obtained either f
...
SLOVENSKI STANDARD
oSIST prEN 408:2009
01-maj-2009
Lesene konstrukcije - Konstrukcijski les in lepljeni lamelirani les - Ugotavljanje
nekaterih fizikalnih in mehanskih lastnosti
Timber Structures - Structural timber and glued laminated timber - Determination of
some physical and mechanical properties
Holzbauwerke - Bauholz für tragende Zwecke und Brettschichtholz - Bestimmung einiger
physikalischer und mechanischer Eigenschaften
Structures en bois - Bois de structure et bois lamellé-collé - Détermination de certaines
propriétés physiques et mécaniques
Ta slovenski standard je istoveten z: prEN 408
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
79.060.99 'UXJHOHVQHSORãþH Other wood-based panels
91.080.20 Lesene konstrukcije Timber structures
oSIST prEN 408:2009 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 408:2009
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oSIST prEN 408:2009
EUROPEAN STANDARD
DRAFT
prEN 408
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2009
ICS 79.040; 79.060.99; 91.080.20 Will supersede EN 408:2003
English Version
Timber Structures - Structural timber and glued laminated timber
- Determination of some physical and mechanical properties
Structures en bois - Bois de structure et bois lamellé-collé - Holzbauwerke - Bauholz für tragende Zwecke und
Détermination de certaines propriétés physiques et Brettschichtholz - Bestimmung einiger physikalischer und
mécaniques mechanischer Eigenschaften
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 124.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 408:2009: E
worldwide for CEN national Members.
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oSIST prEN 408:2009
prEN 408:2009 (E)
Contents Page
Foreword .4
Introduction .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Symbols and abbreviations .5
5 Determination of dimensions of test pieces .7
6 Determination of moisture content of test pieces .7
7 Determination of density of test pieces .7
8 Conditioning of test pieces .7
9 Determination of local modulus of elasticity in bending .8
9.1 Test piece .8
9.2 Procedure .8
9.3 Expression of results .9
10 Determination of global modulus of elasticity in bending . 10
10.1 Test piece . 10
10.2 Procedure . 10
10.3 Expression of results . 11
11 Determination of the shear modulus . 12
11.1 Torison method . 12
11.1.1 Test piece . 12
11.1.2 procedure . 12
11.1.3 Expression of results . 14
11.2 Shear field test method . 14
11.2.1 Test piece . 14
11.2.2 Procedure . 14
11.2.3 Expression of results . 16
NOTE . For non rectangular cross-section structural engineering principals apply. 17
12 Determination of modulus of elasticity in tension parallel to the grain . 17
12.1 Test piece . 17
12.2 Procedure . 17
12.3 Expression of results . 17
13 Determination of tension strength parallel to the grain. 18
13.1 Test piece . 18
13.2 Procedure . 18
13.3 Expression of results . 18
14 Determination of modulus of elasticity in compression parallel to the grain . 19
14.1 Test piece . 19
14.2 Procedure . 19
14.3 Expression of results . 19
15 Determination of compression strength parallel to grain . 20
15.1 Test piece . 20
15.2 Procedure . 20
2
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oSIST prEN 408:2009
prEN 408:2009 (E)
15.3 Expression of results . 20
16 Determination of tension and compression strengths perpendicular to the grain . 20
16.1 Requirements for test pieces . 20
16.1.1 Fabrication . 20
16.1.2 Surface preparation . 21
16.2 Procedure . 21
16.3 Expression of results . 23
16.3.1 Compression perpendicular to the grain . 23
16.3.2 Tension perpendicular to the grain . 24
17 Determination of modulus of elasticity perpendicular to the grain . 24
17.1 Requirements for test pieces . 24
17.2 Procedure . 24
17.3 Expression of results . 24
17.3.1 Compression perpendicular to the grain . 24
17.3.2 Tension perpendicular to the grain . 25
18 Determination of shear strength parallel to the grain . 26
18.1 Requirements for test pieces . 26
18.1.1 Fabrication . 26
18.1.2 Surface preparation . 26
18.2 Procedure . 27
18.3 Expression of results . 28
19 Bending strength parallel to grain . 28
19.1 Test Piece . 28
19.2 Procedure . 28
19.3 Expression of results . 30
20 Test report . 30
20.1 General . 30
20.2 Test piece . 30
20.3 Test method . 30
20.4 Test results . 31
Annex A (informative) Example of compression perpendicular to grain test arrangement . 32
Annex B (informative) Example of tension perpendicular to grain test arrangement with rigid
fixings . 34
3
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oSIST prEN 408:2009
prEN 408:2009 (E)
Foreword
This document (prEN 408:2009) has been prepared by Technical Committee CEN/TC 124 “Timber structures”,
the secretariat of which is held by SFS.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 408:2003.
In this revised standard a new parallel to grain shear test is to replace the one in EN 408:2003
Annexes A and B are informative.
Introduction
This 2007 revision replaces the test for the determination of the shear strength parallel to grain.
The revised edition of 2003 added a global bending modulus of elasticity, whilst renaming the existing test as
the local modulus of elasticity. It also includes the methods for determination of shear strength and
mechanical properties perpendicular to the grain, previously given in EN 1193 which has now 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, etc., 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.
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oSIST prEN 408:2009
prEN 408:2009 (E)
1 Scope
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, and density of test pieces 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.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text, and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to
this European Standard only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies (including amendments).
Moisture content of a piece of sawn timber - Part 1: Determination by oven dry method
EN 13183-1
3 Terms and definitions
None.
4 Symbols and abbreviations
ϕ rotation, in radians
χ, η shape factors
A cross-sectional area, in square millimetres;
a distance between a loading position and the nearest support in a bending test, in millimetres;
b width of cross section in a bending test, or the smaller dimension of the cross section, in
millimetres;
E modulus of elasticity in compression parallel to the grain, in newtons per square millimetre;
c,0
E modulus of elasticity in compression perpendicular to the grain, in newtons per square millimetre;
c,90
E global modulus of elasticity in bending, in newtons per square millimetre;
m,g
E local modulus of elasticity in bending, in newtons per square millimetre;
m,l
E apparent modulus of elasticity in bending, in newtons per square millimetre;
m,app
E modulus of elasticity in tension parallel to the grain, in newtons per square millimetre;
t,0
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E modulus of elasticity in tension perpendicular to the grain, in newtons per square millimetre;
t,90
F load, in newtons;
F compressive load perpendicular to the grain, in newtons;
c,90
F maximum compressive load perpendicular to the grain, in newtons;
c,90,max
F estimated maximum compressive load perpendicular to the grain, in newtons;
c,90,max,est
F maximum load, in newtons;
max
F estimated maximum load, in newtons;
max,est
F tensile load perpendicular to the grain, in newtons;
t,90
F maximum tensile load perpendicular to the grain, in newtons;
t,90,max
S first moment of area, in millimetres to the third power;
f compressive strength parallel to the grain, in newtons per square millimetre;
c,0
f compressive strength perpendicular to the grain, in newtons per square millimetre;
c,90
f bending strength, in newtons per square millimetre;
m
f tensile strength parallel to the grain, in newtons per square millimetre;
t,0
f tensile strength perpendicular to the grain, in newtons per square millimetre;
t,90
f shear strength parallel to the grain, in newtons per square millimetre;
v,z
f characteristic shear strength parallel to the grain, in newtons per square millimetre;
v,k
G shear modulus, in newtons per square millimetre;
G shear modulus in torsion, in newtons per square millimetre;
tor,t
G shear modulus in shear field, in newtons per square millimetre; h depth of cross section in a
tor,s
bending test, or the larger dimension of the cross section, or the test piece height in
perpendicular to grain and shear tests, in millimetres;
h gauge length, in millimetres;
0
I second moment of area, in millimetres to the fourth power;
K, k coefficients;
k coefficient for shear modulus;
G
k torque stiffness;newton metre per radian;
ror
k shear stiffness;
s
l span in bending, or length of test piece between the testing machine grips in compression and
tension or torsion, in millimetres;
l gauge length for the determination of modulus of elasticity or shear modulus, in millimetres;
1
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T plate thickness, in millimetres;
T torque, in newton millimetres;
r
V is the shear force, in newton;
s
W section modulus, in millimetres to the third power;
w deformation, in millimetres;
Suffixes
1, 2 refer to loads or deformations or pieces at particular points of a test and are referred to as
necessary in the text.
5 Determination of dimensions of test pieces
The dimensions of the test piece shall be measured to an accuracy of 1%. All measurements shall be made
when the test pieces are conditioned as specified in clause 8. If the width or thickness varies within a test
piece, these dimensions should be recorded as the average of three separate measurements taken at
different positions on the length of each piece.
The measurements shall not be taken closer than 150 mm to the ends.
Specimens for perpendicular to grain tests shall be planed.
6 Determination of moisture content of test pieces
The moisture content of the test piece shall be determined in accordance with EN 13183-1 on a section taken
from the test piece. For structural timber the section shall be of full cross section, free from knots and resin
pockets. For perpendicular to grain test specimens the moisture content shall be determined from the whole
specimen.
In strength tests for bending and tension parallel to grain and compression parallel to grain, the section shall
be cut as close as possible to the fracture.
7 Determination of density of test pieces
The density of the whole cross section of the test piece shall be determined on a section taken from the test
piece. For structural timber the section shall be of full cross section, free from knots and resin pockets.
In strength tests, the section shall be cut as close as possible to the fracture.
For perpendicular to grain test specimens the density of the test pieces shall be determined prior to test after
conditioning from the measurements of mass and volume of the whole test piece.
8 Conditioning of test pieces
o
All tests shall be carried out on pieces, which are conditioned at the standard environment of (20 ± 2) C and
(65 ± 5) % relative humidity. A test piece is conditioned when it attains constant mass. Constant mass is
considered to be attained when the results of two successive weighings, carried out at an interval of 6 h, do
not differ by more than 0,1% of the mass of the test piece.
Where the timber to be tested is not readily conditionable to the above standard environment (e.g. for
hardwoods with high densities), that fact shall be reported.
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For small specimens, unless otherwise protected, test pieces shall not be removed from the conditioning
environment more than 1 h before testing.
NOTE Test pieces can be stored in the test area for up to 24 h provided they are close piled and wrapped in vapour
tight sheeting.
9 Determination of local modulus of elasticity in bending
9.1 Test piece
The test piece shall have a minimum length of 19 times the depth of the section. Where this is not possible,
the span of the beam shall be reported.
9.2 Procedure
The test piece shall be symmetrically loaded in bending at two points over a span of 18 times the depth as
shown in Figure 1. If the test piece and equipment do not permit these conditions to be achieved exactly, the
distance between the load points and the supports may be changed by an amount not greater than 1,5 times
the piece depth, and the span and test piece length may be changed by an amount not greater than three
times the piece depth, while maintaining the symmetry of the test.
The test piece shall be simply supported.
NOTE Small steel plates of length not greater than one-half of the depth of the test piece may be inserted between
the piece and the loading heads or supports to minimize local indentation.
Lateral restraint shall be provided as necessary to prevent buckling. This restraint shall permit the piece to
deflect without significant frictional resistance.
Load shall be applied at a constant rate. The rate of movement of the loading head shall be not greater than
0,003 h mm/s (see Figure 1).
The maximum load applied shall not exceed the 0,4 F .
max
Figure 1 — Test arrangement for measuring local modulus of elasticity in bending
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The loading equipment used shall be capable of measuring the load to an accuracy of 1 % of the load applied
to the test piece or, for loads less than 10 % of the applied maximum load, with an accuracy of 0,1 % of the
maximum applied load.
The deformation w shall be taken as the average of measurements on both faces at the neutral axis, and shall
be measured at the centre of a central gauge length of five times the depth of the section.
The measuring equipment used shall be capable of measuring deformation to an accuracy of 1 % or, for
deformations less than 2 mm, with an accuracy of 0,02 mm.
9.3 Expression of results
Using data obtained from the local modulus of elasticity test, plot the load/deformation graph.
Use that section of the graph between 0,1F and 0,4 F for a regression analysis.
max max
Find the longest portion of this section that gives a correlation coefficient of 0,99 or better. Provided that this
portion covers at least the range 0,2 F to 0,3 F , calculate the local modulus of elasticity from the
max max
following expression:
2
al F − F
()
1 21
E =
ml,
16Iw −w
()
21
where
F - F is an increment of load in newtons on the regression line with a correlation coefficient of 0,99 or
2 1
better and
w - w is the increment of deformation in millimetres corresponding to F - F (see Figure 2).
2 1 2 1
The local modulus of elasticity shall be calculated to an accuracy of 1 %.
If a portion of the graph cannot be found with a correlation coefficient of 0,99 or better covering the range
0,2 F to 0,3 F , check the test equipment and take measures to eradicate any errors caused by distorted
max max
specimens. If 0,99 is still not achieved, discard the specimen.
The modulus of elasticity shall be calculated to an accuracy of 1 %.
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Key
1) Load
2) Deformation
Figure 2 — Load-deformation graph within the range of elastic deformation
10 Determination of global modulus of elasticity in bending
10.1 Test piece
The test piece shall have a minimum length of 19 times the depth of the section. Where this is not possible,
the span of the beam shall be reported.
10.2 Procedure
The test piece shall be symmetrically loaded in bending at two points over a span of 18 times the depth as
shown in Figure 3. If the test piece and equipment do not permit these conditions to be achieved exactly, the
distance between the load points and the supports may be changed by an amount not greater than 1,5 times
the piece depth, and the span and test piece length may be changed by an amount not greater than three
times the piece depth, while maintaining the symmetry of the test.
The test piece shall be simply supported.
NOTE 1 Small steel plates of length not greater than one-half of the depth of the
...
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