SIST EN 14358:2016

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.GQRVWLHolzbauwerke - Berechnung und Kontrolle charakteristischer WerteStructures en bois - Détermination et vérification des valeurs caractéristiquesTimber structures - Calculation and verification of characteristic values91.080.20Lesene konstrukcijeTimber structuresICS:Ta slovenski standard je istoveten z:EN 14358:2016SIST EN 14358:2016en,fr,de01-september-2016SIST EN 14358:2016SLOVENSKI
STANDARDSIST EN 14358:20071DGRPHãþD



SIST EN 14358:2016



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14358
June
t r s x ICS
y {ä r v râ
{ sä r z rä t r Supersedes EN
s v u w zã t r r xEnglish Version
Timber structures æ Calculation and verification of characteristic values Structures en bois æ Détermination et vérification des valeurs caractéristiques
Holzbauwerke æ Berechnung und Kontrolle charakteristischer Werte This European Standard was approved by CEN on
t u January
t r s xä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels
9
t r s x CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s v u w zã t r s x ESIST EN 14358:2016



EN 14358:2016 (E) 2 Contents Page European foreword . 3 1 Scope . 4 2 Symbols . 4 3 Calculation of characteristic properties from test results in the frame of initial type testing . 5 3.1 General . 5 3.2 Calculation of 5 and 95 percentiles values. 5 3.2.1 General . 5 3.2.2 Parametric calculation . 5 3.2.3 Non parametric calculation . 7 3.3 Calculation of characteristic mean values . 7 4 Calculation of characteristic properties from test results in the frame of internal factory production control . 9 4.1 General . 9 4.2 Calculation of characteristic strength, density or resistance properties (5-percentile) . 9 4.3 Calculation of characteristic stiffness properties (mean values) . 11 5 Acceptance procedure for verification of a lot . 12 5.1 General . 12 5.2 Verification of mean values (e.g. mean modulus of elasticity) . 12 5.2.1 Method keeping the consumer’s risk at 10 % . 12 5.2.2 Alternative method limiting the sample size for large COVs . 13 5.3 Verification of 5-percentile values (e.g. characteristic strength) . 13 5.3.1 Method with consumer's risk equal to 10 % . 13 5.3.2 Alternative method limiting the sample size for large COVs . 14 Bibliography . 15
SIST EN 14358:2016



EN 14358:2016 (E) 3 European foreword This document (EN 14358:2016) 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 December 2016, and conflicting national standards shall be withdrawn at the latest by December 2016. 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 14358:2006. This document is based on Annex D of EN 1990:2002, Eurocode – Basis of structural design. Compared to EN 14358:2006, the following modifications have been made: — integration of normal distributions, and non parametric estimation; — proposals for simplified equations to evaluate correction factors; — estimation of mean values; — acceptance procedure for verification of a lot (taken from EN 384: 2010). 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 14358:2016



EN 14358:2016 (E) 4 1 Scope This standard gives statistical methods for the determination of characteristic values from test results on a sample drawn from a clearly defined reference population of e.g. solid wood, fasteners, connectors and wood-based products. The characteristic value is an estimate of the property of the reference population and can be based on a 5-percentile value of strength, resistance or density as well as on a mean value for stiffness. Parametric methods are given for the determination of lower and upper 5-percentiles. The upper 5-percentile is the 95-percentile. This standard is suitable for use with any structural product in the frame of type testing as well as factory production control. Sampling is not covered by this document, but reference is made to the relevant product standards. This standard also provides the acceptance procedure for verification of a lot. Depending on the product, characteristic values determined in accordance with this standard may be used directly or may need additional adjustments specified in the relevant product standards. Note: For example, in the case of solid timber, specific adjustment factors for calculation of characteristic values are given in EN 384. 2 Symbols s()kn Factor used to calculate characteristic properties for initial type testing (see Tables 1 and 2) ()kn Factor used to calculate characteristic properties for factory production control (see Tables 3 and 4) mi Individual test value i of stochastic variable m mk 5-percentile value of stochastic variable m meanm Population mean value of stochastic variable m n Number of test values sy Standard deviation ux x-percentile in the standardised normal distribution y Sample mean value
— y = m for normally distributed variable
— y = ln m for logarithmically normally distributed variable 5.0y Sample 5-percentile from the test data α Confidence level (%) SIST EN 14358:2016



EN 14358:2016 (E) 5 3 Calculation of characteristic properties from test results in the frame of initial type testing 3.1 General The characteristic value of a material parameter or a resistance shall be determined at a confidence level of
= 75 %, where the confidence level
is defined as the probability of which the characteristic value is greater than the estimator on the characteristic value. NOTE
= 75 % corresponds to the value recommended in EN 1990. 3.2 Calculation of 5 and 95 percentiles values 3.2.1 General a) The characteristic value kmfor a material strength parameter or a resistance m modelled as a stochastic variable is defined as the p-percentile in the distribution function for m, corresponding to an assumed infinitely large test series; b) p = 5 % shall be assumed. 3.2.2 Parametric calculation a) The parametric approach shall not be used on test data not fitting the assumed distribution. In that case, a non-parametric method should be used; b) It is assumed that n test values are available and that these may be assumed to originate from a statistically homogeneous population. The test values, which are assumed to be logarithmically normally distributed or normally distributed and independent, are denoted 12,,,nmmm. The n test values constitute the sample; c) Strength parameters should be assumed as logarithmically normally distributed unless analysis of the data shows that a normal distribution is more appropriate. Density shall be assumed as normally distributed; NOTE Some product standards define the statistical distribution to be used. d) The mean value y and the standard deviation sy shall be determined as:
logarithmically normally distributed normally distributed
==∑11lnniiymn (1) ==∑11niiymn (2)
=−=−∑211(ln)max10,05niyimysn (3) =−=−∑211()max10,05niyimysny (4) The sample coefficient of variation shall not be taken as less than 0,05. For logarithmically normally distributed test values, the standard deviation sy shall not be less than()+≈2ln10,050,05. SIST EN 14358:2016



EN 14358:2016 (E) 6 For normally distributed test values, the standard deviation sy shall not be less than0,05y. e) The characteristic value of the sample shall be determined as follows: percentile logarithmically normally distributed normally distributed 5-percentile ()=−ksy
exp()mykns (5) =−k
...