EN 14358-2006 3776 Timber structures - Calculation of characteristic 5-percentile values and acceptance criteria for a sample《建筑木材 5%特征值计算和样品的验收标准》.pdf

1、BRITISH STANDARDBS EN 14358:2006Timber structures Calculation of characteristic 5-percentile values and acceptance criteria for a sampleThe European Standard EN 14358:2006 has the status of a British StandardICS 79.040; 91.080.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40

2、g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIBS EN 14358:2006This British Standard was published under the authority of the S

3、tandards Policy and Strategy Committee on 31 January 2007 BSI 2007ISBN 978-0-580-49962-3National forewordThis British Standard was published by BSI. It is the UK implementation of EN 14358:2006.The UK participation in its preparation was entrusted to Technical Committee B/518, Structural timber.A li

4、st of organizations represented on B/518 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligat

5、ions. Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14358 December 2006 ICS 79.040; 91.080.20 English Version Timber structures - Calculation of

6、characteristic 5-percentile values and acceptance criteria for a sample Structures en bois - Dtermination des valeurs correspondant au fractile 5 % dexclusion infrieure et critres dacceptation pour un chantillon Holzbauwerke - Berechnung der 5%-Quantile fr charakteristische Werte und Annahmekriterie

7、n fr ProbenThis European Standard was approved by CEN on 25 October 2006. 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 bibliogr

8、aphical references concerning such national standards 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 translation under the responsibility of a

9、CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latv

10、ia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brus

11、sels 2006 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14358:2006: ELicensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 14358:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative ref

12、erences 4 3 Symbols 4 4 Calculation of characteristic values from test results.5 5 Acceptance criteria for a sample .6 Bibliography 8 Licensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 14358:2006 (E) 3 Foreword This document (EN 14358:2006) has been prepare

13、d by Technical Committee CEN/TC 124 “Timber Structures“, the secretariat of which is held by SFS. This document (EN 14358:2006) is based on Annex D of EN 1990:2002, Eurocode Basis of structural design. This European Standard shall be given the status of a national standard, either by publication of

14、an identical text or by endorsement, at the latest by June 2007, and conflicting national standards shall be withdrawn at the latest by June 2007. It is anticipated that the standard will replace the corresponding parts of EN 1058: Wood-based panels Determination of characteristics values of mechani

15、cal properties and density. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN/CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national s

16、tandards organizations of the following countries 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

17、, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 14358:2006 (E) 4 1 Scope This document specifies a method for the determination of characteristic 5-percentile values from test

18、results for fasteners and wood-based products. This document also gives corresponding acceptance criteria for a sample. Structural timber is not covered by this document but by EN 384. Sampling is not covered by this document, but reference is made to the relevant product standards. 2 Normative refe

19、rences Not applicable. 3 Symbols kn Factor (see Table 2) ks Factor (see Table 1) miTest value mkCharacteristic value n Number of test values sy Standard deviation uxx-fractile in the standardised normal distribution y Stochastic value, yi= lnmi y Mean value Confidence level (%) Licensed Copy: Wang B

20、in, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 14358:2006 (E) 5 4 Calculation of characteristic values from test results 4.1 The characteristic value of a material parameter or a resistance shall be determined at a confidence level of = 75 %, where the confidence level is d

21、efined as the probability of which the characteristic value is greater than the estimator on the characteristic value. NOTE The confidence level = 75 % corresponds to the value recommended in EN 1990. 4.2 The characteristic value of mkfor a material strength parameter or a resistance m modelled as a

22、 stochastic variable is defined as the p -percentile in the distribution function for m , corresponding to an assumed infinitely large test series. 4.3 p = 5 % shall be assumed. 4.4 It is assumed that n test values are available and that these may be assumed to originate from a homogeneous populatio

23、n. The test values, which are assumed to be logarithmically normally distributed and independent, are denoted m1, m2,. mn. 4.5 The mean value y and the standard deviation syfor the stochastic variable y = ln m shall be determined as =niimny1ln1(1) =niiyymns12)(ln11(2) 4.6 The characteristic value sh

24、all be determined as mk= exp( y - kssy) (3) where ks is given in Table 1. NOTE ksis determined as: nkks= where k is the -percentile in a non-central t-distribution with n-1 degrees of freedom and the non-centrality parameter nup=1 . u1-pis the (1 p) percentile of the standardised normal distribution

25、 function. 4.7 The coefficient of variation shall not be assumed to be less than 0,05. Use the value sy = 0,05 in equation mk = exp ( y - kssy) in the case where coefficient of variation is less than 0,05. Licensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN

26、14358:2006 (E) 6 Table 1 - Factor ksvalues Number of test specimens Factor n ks3 3,155 2,4610 2,10 15 1,9920 1,9330 1,87 50 1,81100 1,76500 1,71 1,65 5 Acceptance criteria for a sample 5.1 If a variable control method is applied to control of material parameters or resistance, such control method sh

27、all be composed with a significance level of = 75 %, where the significance level is defined as the probability of not accepting a delivery having the required characteristic value. NOTE The significance level = 75 % corresponds to the value required in Clause 4. 5.2 It is assumed that n test values

28、 are available and that these may be assumed to be derived from a homogeneous population described by the stochastic variable m. The test values which are assumed to be logarithmically normally distributed, are denoted m1, m2,. mn. 5.3 The mean value y and the standard deviation syfor the stochastic

29、 variable y = mln shall be determined as: =niimny1ln1(4) =niiyymns12)(ln11(5) 5.4 The control shall be performed by showing that, for the random sample with n test specimens ()exp ( )y kykns m(6) where mk is the assumed characteristic value 5.5 If the standard deviation is unknown from prior knowled

30、ge, the coefficient k(n) shall be taken as ks(see 4.6 and Table 1) 5.6 If the standard deviation is known, e.g. from production control of a period of 1 year or more, the coefficient k(n) shall be taken as: Licensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN

31、 14358:2006 (E) 7 1()pukn un=+(7) where u1-p is the (1-p) percentile of the standardised normal distribution function (p = 5% shall be assumed); u is the percentile of the standardised normal distribution function ( = 75% shall be assumed). The values of k(n) for known standard deviation are given i

32、n Table 2 Table 2 - Factor k(n) values Number of test specimens Factor n k(n)3 2.03 5 1.9510 1.8615 1.82 20 1.8 30 1.7750 1.74 100 1.69500 1.67 1.65 Licensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEN 14358:2006 (E) 8 Bibliography 1 EN 384, Structural timber

33、 Determination of characteristic values of mechanical properties and density 2 EN 789, Timber structures Test methods Determination of mechanical properties of wood based panels 3 EN 1058, Wood-based panels Determination of characteristics values of mechanical properties and density 4 EN 1990, Euroc

34、ode Basis of structural design 5 EN 1995-1-1, Eurocode 5: Design of timber structures Part 1-1: General - Common rules and rules for buildings Licensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 2007, Uncontrolled Copy, (c) BSIblankLicensed Copy: Wang Bin, na, Fri Mar 23 02:08:35 GMT+00:00 20

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