1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 8970:2010Timber structures Testing ofjoints made with mechanicalfasteners Requirements forwood density (ISO 8970:2010)BS EN ISO 8970:2010 BRITISH STANDARDNational forew
2、ordThis British Standard is the UK implementation of EN ISO 8970:2010.It supersedes BS EN 28970:1991 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee B/518, Structural timber.A list of organizations represented on this committee can beobtained on request
3、 to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 65918 8ICS 91.080.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard
4、 was published under the authority of theStandards Policy and Strategy Committee on 31 August 2010Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 8970 June 2010 ICS 91.080.20 Supersedes EN 28970:1991English Version Timber structures - Tes
5、ting of joints made with mechanical fasteners - Requirements for wood density (ISO 8970:2010) Structures en bois - Essai des assemblages raliss par organes mcaniques - Exigences concernant la masse volumique du bois (ISO 8970:2010) Holzbauwerke - Prfung von mechanischen Verbindungen -Anforderungen a
6、n die Rohdichte des Holzes (ISO 8970:2010) This European Standard was approved by CEN on 12 June 2010. 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.
7、Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN 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
8、 under the responsibility of a CEN member into its own language and notified to the CEN 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, France, Ger
9、many, Greece, Hungary, Iceland, Ireland, Italy, Latvia, 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 NORMUN
10、G Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 8970:2010: EBS EN ISO 8970:2010EN ISO 8970:2010 (E) 3 Foreword This document (EN ISO 8970:2010) has been prepared by Te
11、chnical Committee ISO/TC 165 “Timber structures” in collaboration with 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,
12、at the latest by December 2010, and conflicting national standards shall be withdrawn at the latest by December 2010. 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
13、 any or all such patent rights. This document supersedes EN 28970:1991. 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, Denma
14、rk, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 8970:2010 has been approved
15、 by CEN as a EN ISO 8970:2010 without any modification. BS EN ISO 8970:2010ISO 8970:2010(E) ISO 2010 All rights reserved iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internationa
16、l Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO,
17、also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical commi
18、ttees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the po
19、ssibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 8970 was prepared by Technical Committee ISO/TC 165, Timber structures. This second edition cancels and replaces the first ed
20、ition (ISO 8970:1989), which has been technically revised. BS EN ISO 8970:2010ISO 8970:2010(E) iv ISO 2010 All rights reservedIntroduction The need to prescribe restriction of density for timber connection tests dates back many decades. In using the standard density, the boundaries set are considere
21、d too restrictive. This leads to difficulties in sampling timber elements and increased laboratory testing costs. Moreover, evidence has surfaced that the effect of density on the load-bearing capacity of connections is in many cases less significant than expected, and that many other parameters inf
22、luence it. BS EN ISO 8970:2010INTERNATIONAL STANDARD ISO 8970:2010(E) ISO 2010 All rights reserved 1Timber structures Testing of joints made with mechanical fasteners Requirements for wood density 1 Scope This International Standard specifies a method, based on density, for the selection of pieces o
23、f wood used in determining the strength and stiffness properties of connections made with mechanical fasteners. It is assumed the wood density is normally distributed and that any deviations are reported. This International Standard is applicable only to specimens of wood. NOTE It is emphasized that
24、 the wood density is only one of the properties that can influence the strength of a joint. Other relevant properties are, for example, growth-ring size, slope of grain, toughness and hardness. 2 Normative references The following referenced documents are indispensable for the application of this do
25、cument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3131, Wood Determination of density for physical and mechanical tests 3 Symbols and units k factor is the standard deviation, ex
26、pressed in kilograms per cubic metre is the density of the wood to which the test results should be applied, expressed in kilograms per cubic metre mis the mean wood density to which the test results should be applied, expressed in kilograms per cubic metre m,selis the mean wood density of all selec
27、ted pieces to which the test results should be applied, expressed in kilograms per cubic metre 4 Timber sampling method and requirements 4.1 General This International Standard specifies a method for the selection of wood of the required density. The density shall be determined in accordance with IS
28、O 3131, with mass and volume corresponding to equilibrium at a temperature of (20 2) C and relative humidity of (65 5) %. BS EN ISO 8970:2010ISO 8970:2010(E) 2 ISO 2010 All rights reservedIf other conditions, such as tropical conditions, are used, they shall be permitted and reported. The data shoul
29、d be adjusted at the specific moisture content relative to those conditions. 4.2 Sampling method and requirements The sampling method is based on the principle that all selected pieces have a density comparable with that of the wood to which the connection test results shall be applied. The test dat
30、a may be used directly for calculating characteristic values, etc. of the joints. NOTE The wood density relates to one wood species or a group of wood species. The wood shall be of uniform quality and without localized defects that can influence the test results. The wood density, , of all selected
31、pieces shall satisfy the condition given by Equation (1): (1 k)mu u (1 + k)m(1) where mis the mean density of the wood to which the test results are applied; k is equal to 1,6 /mor 0,25 for cases where is unknown; is the standard deviation of the wood to which the test results are applied. The mean
32、wood density, m,sel, of all selected pieces shall satisfy the condition given by Equation (2): 0,95mu m,selu 1,05m(2) where mis the mean density of the wood to which the test results are applied; m,selis the mean density of all selected pieces. 5 Test report The following information shall be includ
33、ed in the test report: a) reference to this International Standard, i.e. ISO 8970:2010; b) the wood species or wood species group; c) the moisture content at the time of selection; d) the mean density including the (assumed) standard deviation of the wood to which the test result should be applied;
34、e) the density distribution of the selected pieces; f) the mean density of all selected pieces; g) confirmation that the selected pieces satisfy the conditions mentioned in this International Standard; h) any other information which can influence the use of the test results. BS EN ISO 8970:2010ISO 8
35、970:2010(E) ISO 2010 All rights reserved 3Bibliography 1 LEIJTEN, A.J.M., KHLER, J., JORISSEN, A.J.M., Timber density restrictions for timber connection tests according to ISO 8970/EN 28970, In: Proceedings of CIB-W18, paper 39-21-1, 2006 This page deliberately left blankThis page deliberately left
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