SIST EN 384:2004
(Main)Structural timber - Determination of characteristic values of mechanical properties and density
Structural timber - Determination of characteristic values of mechanical properties and density
This standard gives a method for determining characteristic values of mechanical properties and density, for defined populations of timber of visual/or mechanical strength grades. A method is also given for checking the strength of a timber sample against its designated value. The values determined is in accordance with this standard for mechanical properties and density are suitable for assigning grade and species to the strength classes of EN 338.
Bauholz für tragende Zwecke - Bestimmung charakteristischer Werte für mechanische Eigenschaften und Rohdichte
Diese Norm beschreibt, wie charakteristische Werte für mechanische Eigenschaften und Rohdichtewerte von Holz definierter Grundgesamtheiten zu bestimmen sind. Grundgesamtheiten im Sinne dieser Norm sind visuell und/oder maschinell festigkeitssortierte Sortierklassen.
Außerdem wird ein Verfahren zur Überprüfung der Festigkeitswerte einer Probe zum Vergleich mit genormten Festigkeitswerten angegeben.
Die nach dieser Norm bestimmten mechanischen Eigenschaften und Rohdichtewerte sind für die Zuordnung der Holzarten und -klassen in die Festigkeitsklassen nach EN 338 geeignet.
ANMERKUNG Für die Zuordnung der Holzarten und -klassen in die Festigkeitsklassen nach EN 338 ist die Bestimmung von nur drei charakteristischen Werten d. h. Biegefestigkeit, Mittelwert des Elastizitätsmoduls parallel zur Faserrichtung und der Rohdichte, erforderlich. Die übrigen Eigenschaften können der in Tabelle 338 angegebenen Tabelle entnommen werden
Bois de structure - Détermination des valeurs caractéristiques des propriétés mécaniques et de la masse volumique
Konstrukcijski les - Ugotavljanje značilnih vrednosti mehanskih lastnosti in gostote
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.JRVWRWHBauholz für tragende Zwecke - Bestimmung charakteristischer Werte für mechanische Eigenschaften und RohdichteBois de structure - Détermination des valeurs caractéristiques des propriétés mécaniques et de la masse volumiqueStructural timber - Determination of characteristic values of mechanical properties and density91.080.20Lesene konstrukcijeTimber structuresICS:Ta slovenski standard je istoveten z:EN 384:2004SIST EN 384:2004en01-september-2004SIST EN 384:2004SLOVENSKI
STANDARDSIST EN 384:19961DGRPHãþD
SIST EN 384:2004
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 384January 2004ICS 79.040Supersedes EN 384:1995English versionStructural timber - Determination of characteristic values ofmechanical properties and densityBois de structure - Détermination des valeurscaractéristiques des propriétés mécaniques et de la massevolumiqueBauholz für tragende Zwecke - Bestimmungcharakteristischer Werte für mechanische Eigenschaftenund RohdichteThis European Standard was approved by CEN on 20 February 2003.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2004 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 384:2004: ESIST EN 384:2004
EN 384:2004 (E)2ContentsPage1Scope.52Normative references.53Terms and definitions.54Symbols and abbreviations.65Mechanical properties determined from full-size specimens.75.1Sampling.75.2Testing.75.3Analysis of data.85.3.1Determination of sample 5-percentile.85.3.2Determination of the sample mean of modulus of elasticity.85.3.3Reference conditions.85.3.4Adjustment factors.85.4Strength properties.95.5Modulus of elasticity.106Density.117Alternative methods of determining mechanical properties.117.1Bending strength and modulus of elasticity determined from small, clear specimens.117.2Other mechanical properties.117.2.1General.117.2.2Tension and compression parallel to grain strength and shear strength.127.2.3Tension perpendicular to grain strength.127.2.4Compression perpendicular to grain strength.127.2.5Characteristic fifth percentile modulus of elasticity parallel to grain.127.2.6Mean modulus of elasticity perpendicular to grain.127.2.7Shear modulus.128Mechanical properties for other grades.129Verification.1310Report.13 (informative)
....................................................................................................................................................14Annex A Bibliography......................................................................................................................................14Annex B (informative)
Sample form containing characteristic values.15SIST EN 384:2004
EN 384:2004 (E)3ForewordThis document (EN 384:2004) has been prepared by Technical Committee CEN/TC 124 “Timber structures”, thesecretariat 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 orby endorsement, at the latest by July 2004, and conflicting national standards shall be withdrawn at the latest byJuly 2004.This document supersedes EN 384:1995.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.SIST EN 384:2004
EN 384:2004 (E)4IntroductionIn this revised edition the method for determining characteristic values from tests on small clear specimens is nowonly permitted for hardwoods. Changes to factor kv and other minor changes have also been made.Structural codes can only function effectively if standard methods of determining the mechanical and physicalproperties exist.Whilst total accuracy of characteristic values for any defined population is an aim, it is recognized that this is notachievable. A major aim of the procedures given in this standard is to produce characteristic values that arecomparable in terms of the populations they represent. It is also important that the standard permits the use of asmuch existing test data as possible from various sampling and testing techniques.Where methods are given to permit characteristic values to be determined from a less than ideal amount ofstructural size test data or from small, clear, defect-free specimen test data, reduction factors to reflect a lowerdegree of confidence are employed.This standard covers the stages of population definition, sampling, testing and analysis of data in the determinationof characteristic values.SIST EN 384:2004
EN 384:200451 ScopeThis standard gives a method for determining characteristic values of mechanical properties and density, fordefined populations of timber of visual and/or mechanical strength grades.A method is also given for checking the strength of a timber sample against its designated value.The values determined in accordance with this standard for mechanical properties and density are suitable forassigning grades and species to the strength classes of EN 338.NOTEFor assigning grades and species to the strength classes in EN 338 only three characteristic values, i.e. bendingstrength, mean modulus of elasticity parallel to grain and density need to be determined, other properties may be taken from thetable in EN 338.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 408:2003, Timber structures - Structural timber and glued laminated timber - Determination of some physicaland mechanical propertiesprEN 14081-1, Timber structures – Strength graded structural timber with rectangular cross section – Part 1:General requirementsISO 3131:1975, Wood - Determination of density for physical and mechanical tests.3 Terms and definitionsFor the purposes of this European Standard, the following terms and definitions apply:3.1characteristic valuegenerally a value that corresponds to a fractile of the statistical distribution of atimber property. For strengthproperties, modulus of elasticity and density the fractile is the 5-percentile. For modulus of elasticity, the meanvalue is also a characteristic value.3.2p-percentilevalue for which the probability of getting lower values is p%.3.3populationmaterial for which the characteristic values are relevant.NOTEThe population is defined by parameters such as species or species grouping, source and strength grade.3.4samplea number of specimens of one cross section size and from one population.3.5small clear testtest to determine mechanical properties of small defect-free specimens.SIST EN 384:2004
EN 384:200463.6specimenpiece of timber for testing.3.7thicknesslesser dimension perpendicular to the longitudinal axis of a piece of timber.3.8widthgreater dimension perpendicular to the longitudinal axis of a piece of timber.3.9depthdimension perpendicular to the longitudinal axis of a timber beam, in the plane of the bending forces.4 Symbols and abbreviations
af
distance between the inner load points of the bending test (in mm)
E
mean modulus of elasticity for one sample (in N/mm2)
E0,mean
mean characteristic value of modulus of elasticity parallel to grain (in N/mm2)
E0,05
5-percentile characteristic value of modulus of elasticity parallel to grain (in N/mm2)
E90,mean
mean characteristic value of modulus of elasticity perpendicular to grain (in N/mm2)
fstrength property
fc,0,k
characteristic value of compression strength parallel to grain (in N/mm2)
fc,90,k
characteristic value of compression strength perpendicular to grain (in N/mm2)
fk
characteristic value of strength (in N/mm2)
fm,k
characteristic value of bending strength (in N/mm2)
fmean
sample mean value of strength (in N/mm2)
fr
5-percentile ranked test value (in N/mm2)
ft,0,k
characteristic value of tensile strength parallel to grain (in N/mm2)
ft,90,k
characteristic value of tensile strength perpendicular to grain (in N/mm2)
f05
5-percentile value for each sample (in N/mm2)
f05
the mean value of f05 for several samples
(in N/mm2)
fv,k
characteristic value of shear strength (in N/mm2)
Gmean
mean characteristic value of shear modulus (in N/mm2)
h
depth of a bending specimen or width of a tension specimen (in mm)
kg
factor used for determining characteristic values of tension and compression parallel to grain and shear
kh
factor for adjusting fk when h is different from 150 mm
kl
factor for adjusting length;SIST EN 384:2004
EN 384:20047
kn
factor for obtaining characteristic value from mean value;
kq
factor for use when checking the quality of a graded sample
ks
factor for adjusting number and size of samples
kv
factor for adjusting machine grading
span (in mm)
es
effective length for the standard test procedure (in mm)
et
effective length for the test (in mm)
n
number of specimens in a sample
s
standard deviation
rsample mean value of density (in N/mm2)
r
density (in kg/m3)
rk
characteristic density (5-percentile) (in kg/m3)
r05
5-percentile density for a sample (in kg/m3)5 Mechanical properties determined from full-size specimens5.1SamplingSamples shall be selected from the population of timber graded visually or by machine to the requirements given inprEN 14081-1. The population shall be capable of being identified at all stages of production and supply, includingthe construction site.The test material shall be representative of the population. The timber shall represent the timber source, sizes, andquality that will be graded in production. Each sample shall be from one source.NOTE 1Any known or suspected difference in the mechanical properties of the population distribution due to growth regions,sawmills, tree size or met
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