1、July 2016 English price group 9No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 79.040!%XLG“2534136www.din.deDIN EN
2、338Structural timber Strength classes;English version EN 338:2016,English translation of DIN EN 338:2016-07Bauholz fr tragende Zwecke Festigkeitsklassen;Englische Fassung EN 338:2016,Englische bersetzung von DIN EN 338:2016-07Bois de structure Classes de rsistance;Version anglaise EN 338:2016,Traduc
3、tion anglaise de DIN EN 338:2016-07SupersedesDIN EN 338:2010-02www.beuth.deDocument comprises 13 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.06.16DIN EN 338:2016-07 2 A comma is used as the decimal marker. National foreword
4、 This document (EN 338:2016) has been prepared by Technical Committee CEN/TC 124 “Timber structures” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was DIN-Normenausschuss Bauwesen (Building and Civil Engineering Standards Committee), Working Committee NA 005-0
5、4-01 AA Holzbau (SpA zu CEN/TC 124, CEN/TC 250/SC 5). Amendments This standard differs from DIN EN 338:2010-02 as follows: a) a new table giving strength classes for softwood species based on tension tests has been added; b) the table giving the strength classes for hardwood species based on edgewis
6、e bending tests has been extended by additional new classes; c) some characteristic values for strength, stiffness and density have been modified; d) the equations to determine the characteristic values of other strength properties from the grade determining properties have been transferred to EN 38
7、4. Previous editions DIN EN 338: 1996-07, 2003-09, 2010-02 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 338 April 2016 ICS 79.040 Supersedes EN 338:2009English Version Structural timber - Strength classes Bois de structure - Classes de rsistance Bauholz fr tragende Zwecke - Festigkeitsklasse
8、n This European Standard was approved by CEN on 30 January 2016. 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 r
9、eferences concerning such national standards may be obtained on application to the CEN-CENELEC 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
10、 CEN member into its own language and notified to the CEN-CENELEC 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, Former Yugoslav Republic of Maced
11、onia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EURO
12、PISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 338:2016 EEN 338:2016 (E) 2 Content Page European foreword 3 Introduction . 4 1 Scope
13、. 5 2 Normative references . 5 3 Terms and definitions 5 4 Symbols and abbreviations 5 5 Classification of structural timber . 6 6 Allocation of a population to a strength class . 10 6.1 Grading 10 6.1.1 Visual graded timber . 10 6.1.2 Machine graded timber . 10 6.2 Classification . 10 6.2.1 Charact
14、eristic values 10 6.2.2 Allocation to a strength class 10 Bibliography 11 DIN EN 338:2016-07 EN 338:2016 (E) 3 European foreword This document (EN 338:2016) has been prepared by Technical Committee CEN/TC 124 “Timber structures”, the secretariat of which is held by AFNOR. This European Standard shal
15、l be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2016, and conflicting national standards shall be withdrawn at the latest by October 2016. Attention is drawn to the possibility that some of the elements of this docu
16、ment 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 338:2009. Compared to EN 338:2009, the following modifications have been made: new table of strength classes for softwood species base
17、d on tension tests; extension with new classes in the table of strength classes for hardwood species based on edgewise bending tests; modification of some characteristic values for strength, stiffness and density; equations to determine the characteristic values of other strength properties from the
18、 grade determining properties has been transferred to EN 384. 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, Estoni
19、a, 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. DIN EN 338:2016-07 EN 338
20、:2016 (E) 4Introduction A strength class system groups together grades, species and sources with similar strength properties thus making them interchangeable. This then permits an engineer to specify a chosen strength class and use the characteristic strength values of that class in design calculati
21、ons. DIN EN 338:2016-07 EN 338:2016 (E) 5 1 Scope This European Standard establishes a system of strength classes for general use in design codes. It gives characteristic strength and stiffness properties and density values for each class to which EN 14081-1 refers. This standard is applicable to al
22、l softwood and hardwood timber for structural use, within the scope of EN 14081-1. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For und
23、ated references, the latest edition of the referenced document (including any amendments) applies. EN 384, Structural timber Determination of characteristic values of mechanical properties and density EN 14081 (all parts), Timber structures Strength graded structural timber with rectangular cross se
24、ction3 Terms and definitions For the purposes of this document, the following term and definition apply. 3.1 population timber of one species or species combination and one source for which the strength, stiffness and density properties apply 4 Symbols and abbreviations Em,0,meanmean characteristic
25、value of modulus of elasticity in bending parallel to grain (in kN/mm2); Et,0,meanmean characteristic value of modulus of elasticity in tension parallel to grain (in kN/mm2); Em,0,k5-percentile characteristic value of modulus of elasticity in bending parallel to grain (in kN/mm2); Et,0,k5-percentile
26、 characteristic value of modulus of elasticity in tension parallel to grain (in kN/mm2); Em,90,meanmean characteristic value of modulus of elasticity in bending perpendicular to grain (in kN/mm2); Et,90,meanmean characteristic value of modulus of elasticity in tension perpendicular to grain (in kN/m
27、m2); fc,0,k5-percentile characteristic value of compressive strength parallel to grain (in N/mm2); fc,90,k5-percentile characteristic value of compressive strength perpendicular to grain (in N/mm2); fm,k5-percentile characteristic value of bending strength (in N/mm2); ft,0,k5-percentile characterist
28、ic value of tensile strength parallel to grain (in N/mm2); ft,90,k5-percentile characteristic value of tensile strength perpendicular to grain (in N/mm2); fv,k5-percentile characteristic value of shear strength (in N/mm2); DIN EN 338:2016-07 EN 338:2016 (E) 6Gmeanmean characteristic value of shear m
29、odulus (in kN/mm2); k5-percentile characteristic value of density (in kg/m3); meanmean characteristic value of density (in kg/m3) 5 Classification of structural timber This standard provides for a number of strength classes, each designated by a number indicating the value of the edgewise bending or
30、 tension strength in N/mm2. For softwood species based on edgewise bending tests, the characteristic values of strength, stiffness and density for the strength classes Cxx, where xx refers to the 5-percentile characteristic bending strength value, are given in Table 1. For softwood species based on
31、tension tests, the characteristic values of strength, stiffness and density for the strength classes Txx, where xx refers to the 5-percentile characteristic tension strength value, are given in Table 2. NOTE 1 Timber belonging to T classes is mainly intended for glulam and other cases where tension
32、is the dominating load. NOTE 2 The T classes correspond to classes L, LS or LD as in EN 140814 with some differences in tabulated properties and is also referred to in EN 14080. For hardwood species based on edgewise bending tests, the characteristic values of strength, stiffness and density for the
33、 strength classes Dxx, where xx refers to the 5-percentile characteristic bending strength value, are given in Table 3. NOTE 3 C and T classes may also be used for hardwoods with similar strength and density profiles such as e.g. poplar or chestnut. The most common used strength classes in Europe ar
34、e printed in bold. DIN EN 338:2016-07 EN 338:2016- 7Table 1 Strength classes for softwood based on edgewise bending tests strength, stiffness and density values Class C14 C16 C18 C20 C22 C24 C27 C30 C35 C40 C45 C50 Strength properties in N/mm2Bending fm,k14 16 18 20 22 24 27 30 35 40 45 50 Tension p
35、arallel ft,0,k7,2 8,5 10 11,5 13 14,5 16,5 19 22,5 26 30 33,5 Tension perpendicular ft,90,k0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 Compression parallel fc,0,k16 17 18 19 20 21 22 24 25 27 29 30 Compression perpendicular fc,90,k2,0 2,2 2,2 2,3 2,4 2,5 2,5 2,7 2,7 2,8 2,9 3,0 Shear fv,k3,0 3,2
36、 3,4 3,6 3,8 4,0 4,0 4,0 4,0 4,0 4,0 4,0 Stiffness properties in kN/mm2Mean modulus of elasticity parallel bending Em,0,mean7,0 8,0 9,0 9,5 10,0 11,0 11,5 12,0 13,0 14,0 15,0 16,0 5 percentile modulus of elasticity parallel bending Em,0,k4,7 5,4 6,0 6,4 6,7 7,4 7,7 8,0 8,7 9,4 10,1 10,7 Mean modulus
37、 of elasticity perpendicular Em,90,mean0,23 0,27 0,30 0,32 0,33 0,37 0,38 0,40 0,43 0,47 0,50 0,53 Mean shear modulus Gmean0,44 0,50 0,56 0,59 0,63 0,69 0,72 0,75 0,81 0,88 0,94 1,00 Density in kg/m35 percentile density k290 310 320 330 340 350 360 380 390 400 410 430 Mean density mean350 370 380 40
38、0 410 420 430 460 470 480 490 520 NOTE 1 Values given above for tension strength, compression strength, shear strength, char. modulus of elasticity in bending, mean modulus of elasticity perpendicular to grain and mean shear modulus have been calculated using the equations given in EN 384. NOTE 2 Th
39、e tension strength values are conservatively estimated since grading is done for bending strength. NOTE 3 The tabulated properties are compatible with timber at moisture content consistent with a temperature of 20 C and a relative humidity of 65 %, which corresponds to a moisture content of 12 % for
40、 most species. NOTE 4 Characteristic values for shear strength are given for timber without fissures, according to EN 408. NOTE 5 These classes may also be used for hardwoods with similar strength and density profiles such as e.g. poplar or chestnut. NOTE 6 The edgewise bending strength may also be
41、used in the case of flatwise bending. DIN EN 338:201607(E)EN 338:2016 (E)8 Table 2 Strength classes for softwood based on tension tests strength, stiffness and density values Class T 8 T 9 T 10 T 11 T 12 T 13 T 14 T 14,5 T 15 T 16 T 18 T 21 T 22 T 24 T 26 T 27 T 28 T 30 Strength properties in N/mm2B
42、ending fm,k13,5 14,5 16 17 18 19,5 20,5 21 22 23 25,5 29 30,5 33 35 36,5 37,5 40 Tension parallel ft,0,k8 9 10 11 12 13 14 14,5 15 16 18 21 22 24 26 27 28 30 Tension perpendicular ft,90,k0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 Compression parallel fc,0,k16 17 17 18 19
43、 20 21 21 21 22 23 25 26 27 28 29 29 30 Compression perpendicular fc,90,k2,0 2,1 2,2 2,2 2,3 2,4 2,5 2,5 2,5 2,6 2,7 2,7 2,7 2,8 2,9 2,9 2,9 3,0 Shear fv,k2,8 3,0 3,2 3,4 3,6 3,8 4,0 4,0 4,0 4,0 4,0 4,0 4,0 4,0 4,0 4,0 4,0 4,0 Stiffness properties in kN/mm2Mean modulus of elasticity parallel tension
44、 Et,0,mean7,0 7,5 8,0 9,0 9,5 10,0 11,0 11,0 11,5 11,5 12,0 13,0 13,0 13,5 14,0 15,0 15,0 15,5 5 percentile modulus of elasticity parallel tension Et,0,k4,7 5,0 5,4 6,0 6,4 6,7 7,4 7,4 7,7 7,7 8,0 8,7 8,7 9,0 9,4 10,1 10,1 10,4 Mean modulus of elasticity perpendicular Et,90,mean0,23 0,25 0,27 0,30 0
45、,32 0,33 0,37 0,37 0,38 0,38 0,40 0,43 0,43 0,45 0,47 0,50 0,50 0,52 Mean shear modulus Gmean0,44 0,47 0,50 0,56 0,59 0,63 0,69 0,69 0,72 0,72 0,75 0,81 0,81 0,84 0,88 0,94 0,94 0,97 Density in kg/m35 percentile density k290 300 310 320 330 340 350 350 360 370 380 390 390 400 410 410 420 430 Mean de
46、nsity mean350 360 370 380 400 410 420 420 430 440 460 470 470 480 490 490 500 520 NOTE 1 Values given above for bending strength, compression strength, shear strength, char. modulus of elasticity in tension, mean modulus of elasticity perpendicular to grain and mean shear modulus have been calculate
47、d using the equations given in EN 384. NOTE 2 The bending strength values are conservatively estimated since grading is done for tension strength. NOTE 3 The tabulated properties are compatible with timber at moisture content consistent with a temperature of 20 C and a relative humidity of 65 %, whi
48、ch corresponds to a moisture content of 12 % for most species. NOTE 4 Characteristic values for shear strength are given for timber without fissures, according to EN 408. NOTE 5 These classes may also be used for hardwoods with similar strength and density profiles such as e.g. poplar or chestnut. N
49、OTE 6 The bending strength may be used in the case of edgewise or flatwise bending. DIN EN 338:2016-07 EN 338:2016 (E)9Table 3 Strength classes for hardwoods based on edgewise bending tests strength, stiffness and density values Class D18 D24 D27 D30 D35 D40 D45 D50 D55 D60 D65 D70 D75 D80 Strength properties in N/mm2Bending fm,k18 24 27 30 35 40 45 50 55 60 65 70 75 80 Tension parallel ft,0,k11 14 16 18 21 24 27 30 33 36 39 42 45 48 Tension perpendicular ft,90,k0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 Compression parallel
