SIST EN 408:2004
(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.
Holzbauwerke - Bauholz für tragende Zwecke und Brettschichtholz - Bestimmung einiger physikalischer und mechanischer Eigenschaften
Diese Europäische Norm legt Prüfverfahren zur Bestimmung folgender Eigenschaften von Bauholz für tragende Zwecke und Brettschichtholz fest: Biege-Elastizitätsmodul, Schubmodul, Biegefestigkeit, Zug-Elastizitätsmodul in Faserrichtung, Zugfestigkeit in Faserrichtung, Druck-Elastizitätsmodul in Faserrichtung, Druckfestigkeit in Faserrichtung, Zug-Elastizitätsmodul rechtwinklig zur Faserrichtung, Zugfestigkeit rechtwinklig zur Faserrichtung, Druck-Elastizitätsmodul rechtwinklig zur Faserrichtung, Druckfestigkeit rechtwinklig zur Faserrichtung sowie die Scherfestigkeit fest.
Zusätzlich wird die Bestimmung der Maße, der Holzfeuchte und der Rohdichte festgelegt.
Die Verfahren gelten 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 a la flexion, le module d'élasticité en traction axiale, la résistance a la traction axiale, le module d'élasticité en compression axiale, la résistance a la compression axiale, le module d'élasticité en traction transversale, la résistance a la traction transversale, le module d'élasticité en compression transversale, la résistance a 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.
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
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 408:2004
01-januar-2004
1DGRPHãþD
SIST EN 1193:2000
SIST EN 408:1996
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: EN 408:2003
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
91.080.20 Lesene konstrukcije Timber structures
SIST EN 408:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 408:2004
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SIST EN 408:2004
EUROPEAN STANDARD
EN 408
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2003
ICS 91.080.20 Supersedes EN 408:1995; EN 1193:1997
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 European Standard was approved by CEN on 20 June 2003.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 408:2003 E
worldwide for CEN national Members.
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SIST EN 408:2004
EN 408:2003 (E)
Contents
page
Foreword.4
Introduction .5
1 Scope .5
2 Normative references.5
3 Terms and definitions .6
4 Symbols and abbreviations.6
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 shear modulus — Single span method .11
11.1 General.12
11.2 Determination of modulus of elasticity in bending.12
11.3 Determination of apparent modulus of elasticity .12
11.3.1 Test piece.12
11.3.2 Procedure.12
11.3.3 Expression of results.13
11.4 Calculation of shear modulus .13
12 Determination of shear modulus — Variable span method .14
12.1 General.14
12.2 Test piece.14
12.3 Procedure.14
12.4 Expression of results .14
12.4.1 General .14
12.4.2 Apparent modulus of elasticity.14
12.4.3 Shear modulus.15
13 Determination of bending strength.16
13.1 Test piece.16
13.2 Procedure.16
13.3 Expression of results .16
14 Determination of modulus of elasticity in tension parallel to the grain.16
14.1 Test piece.16
14.2 Procedure.16
14.3 Expression of results .17
15 Determination of tension strength parallel to the grain .17
15.1 Test piece.17
15.2 Procedure.17
15.3 Expression of results .18
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EN 408:2003 (E)
16 Determination of modulus of elasticity in compression parallel to the grain.18
16.1 Test piece.18
16.2 Procedure.18
16.3 Expression of results.18
17 Determination of compression strength parallel to grain .19
17.1 Test piece.19
17.2 Procedure.19
17.3 Expression of results.19
18 Determination of tension and compression strengths perpendicular to the grain .19
18.1 Requirements for test pieces .19
18.1.1 Fabrication .19
18.1.2 Surface preparation .20
18.2 Procedure.20
18.3 Expression of results.22
18.3.1 Compression perpendicular to the grain.22
18.3.2 Tension perpendicular to the grain .22
19 Determination of modulus of elasticity perpendicular to the grain .22
19.1 Requirements for test pieces .22
19.2 Procedure.22
19.3 Expression of results.23
19.3.1 Compression perpendicular to the grain.23
19.3.2 Tension perpendicular to the grain .24
20 Determination of shear strength parallel to the grain.24
20.1 Requirements for test pieces .24
20.1.1 Fabrication .24
20.1.2 Surface preparation .24
20.2 Procedure.25
20.3 Expression of results.26
21 Test report.26
21.1 General.26
21.2 Test piece.26
21.3 Test method .27
21.4 Test results.27
Annex A (informative) Example of compression perpendicular to grain test arrangement.28
Annex B (informative) Example of tension perpendicular to grain test arrangement with rigid
fixings.30
Bibliography .31
3
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SIST EN 408:2004
EN 408:2003 (E)
Foreword
This document (EN 408:2003) has been prepared by Technical Committee CEN/TC 124, "Structural timber", the
secretariat of which is held by DS.
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 2004, and conflicting national standards shall be withdrawn at the latest
by February 2004.
This document supersedes EN 408:1995 and EN 1193:1997.
Annexes A and B are informative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,
Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
4
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SIST EN 408:2004
EN 408:2003 (E)
Introduction
This revised edition adds 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 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. It is recognized
that the methods may not give the same results.
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.
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.
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
5
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SIST EN 408:2004
EN 408:2003 (E)
3 Terms and definitions
None.
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;
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
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
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
G
shear modulus, 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 tests, in millimetres;
h gauge length, in millimetres;
0
6
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EN 408:2003 (E)
I second moment of area, in millimetres to the fourth power;
K, k coefficients;
k coefficient for shear modulus;
G
span in bending, or length of test piece between the testing machine grips in compression and
tension, in millimetres;
gauge length for the determination of modulus of elasticity, in millimetres;
1
T plate thickness, in millimetres;
W section modulus, in millimetres to the third power;
w deformation, in millimetres;
Suffixes
1, 2 refer to loads or deformations 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
The 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.
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SIST EN 408:2004
EN 408:2003 (E)
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.
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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EN 408:2003 (E)
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
The mean fracture load (F ) of the material under test shall be obtained either from tests on a least 10 pieces of
max
the appropriate species, size and grade or from appropriate existing data.
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 following expression:
max max
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
max
F
to 0,3 , check the test equipment and take measures to eradicate any errors caused by distorted specimens. If
max
0,99 is still not achieved, discard the specimen.
The modulus of elasticity shall be calculated to an
...
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