1、BRITISH STANDARD BS EN 26891:1991 ISO 6891:1983 Timber structures Joints made with mechanical fasteners General principles for the determination of strength and deformation characteristics This European Standard EN26891:1991 has the status of a British StandardBSEN 26891:1991 This British Standard w
2、as published under the authority of the Standards Boardand comes into effect on 31July1991 BSI 01-2000 The following BSI references relate to the work on this standard: Committee referenceTIB/51 Draft for comment82/10367DC ISBN 0 580 19856 1 Cooperating organizations The European Committee for Stand
3、ardization, under whose supervision this European Standard was prepared, comprises the national standards organizations of the following Western European countries. Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen St
4、andardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normunge.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Lu
5、xemburg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse
6、de normalisation UnitedKingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSEN 26891:1991 BSI 01-2000 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN26891 3 National appendix NA (informative) Inside
7、back coverBSEN 26891:1991 ii BSI 01-2000 National foreword This British Standard has been prepared under the direction of the Structural Timber Standards Policy Committee. It is the English language version of EN26891:1991 “Timber structures Joints made with mechanical fasteners General principles f
8、or the determination of strength and deformation characteristics”, published by the European Committee for Standardization (CEN). EN 26891:1991 is identical withISO 6891:1983 published by the International Organization for Standardization (ISO). Clause8 ofEN26891:1991 is technically equivalent to cl
9、auses30 and31 of BS6948:1989 “Mechanically fastened joints in timber and wood based materials”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does
10、 not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theEN title page, pages2to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments inco
11、rporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 26891 February 1991 UDC 694.14:624.011.1:624.042/044:621.882 Descriptors: Timber construction, joining, fasteners, characteristics, mechanical strength, deformation,
12、 loading English version Timber structures Joints made with mechanical fasteners General principles for the determination of strength and deformation characteristics (ISO6891:1983) Structures en bois Assemblages raliss avec des lments mcaniques de fixation Principes gnraux pour la dtermination des c
13、aractristiques de rsistance et de dformation (ISO6891:1983) Holzbauwerke Verbindungen mit mechanischen Verbindungsmitteln Allgemeine Grundstze fr die Ermittlung der Tragfhigkeit und des Verformungsverhaltens (ISO6891:1983) This European Standard was approved by CEN on17January1991 and is identical t
14、o the ISO standard as referred to. 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 references concerning such nati
15、onal 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 CEN member into its own language and no
16、tified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingd
17、om. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels CEN 1991 Copyright reserved to all CEN members Ref. No. EN26891:1991EEN 26891:1991 BSI 01-2000 2 Foreword Based on the positive result
18、 of the Primary Questionnaire procedure, the Technical Board decided by Resolution BT321/1989 to submit the InternationalStandard to the formal vote. The result was positive. In accordance with the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standar
19、d: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the UnitedKingdom. Endorsement notice The text of the International Standard ISO6891:1983 was approved by CEN as a European Standard witho
20、ut any modification. Contents Page Foreword 2 0 Introduction 3 1 Scope 3 2 Field of application 3 3 Reference 3 4 Symbols 3 5 Conditioning of test specimens 3 6 Form and dimensions of test specimens 3 7 Apparatus 3 8 Loading procedure 4 9 Test report 6 Figure 1 Loading procedure 4 Figure 2 Idealized
21、 load-deformation curveandmeasurements 5 ISO 6891:1983 “Timber structures Joints made with mechanical fasteners General principles for the determination of strength and deformation characteristics”EN 26891:1991 BSI 01-2000 3 0 Introduction Developments in the field of load-bearing timber structures
22、require that joints made with mechanical fasteners be tested to obtain information about their strength and deformation (slip) characteristics. This International Standard lays down general principles which should be followed in order to achieve comparability of results from investigations carried o
23、ut in different laboratories. Standard rules for the determination of characteristic strengths for particular types of mechanical fasteners will be given in separate InternationalStandards. This InternationalStandard is based on Joint Recommendations from Working commissionW18, Timber Structures, of
24、CIB 1)and Committee3TT, Timber Testing, ofRILEM 2) , who will also prepare the basis for the above-mentioned supplementary InternationalStandards. 1 Scope This InternationalStandard lays down general principles for the determination of the strength and deformation (slip) characteristics of joints ma
25、de with mechanical fasteners. 2 Field of application This InternationalStandard is applicable to joints made with mechanical fasteners used in statically loaded timber structures. Detailed procedures appropriate to joints made with specific fasteners will be given in separate InternationalStandards.
26、 The principles can also be used for the testing of other joints. It is recognized that for some special types of joints not covered by InternationalStandards, modification of the test procedure may be necessary. 3 Reference ISO 554, Standard atmospheres for conditioning and/or testing Specification
27、s. 4 Symbols Subscripts for the joint slip, v, relate to load points inFigure 2 and are defined in clause8. 5 Conditioning of test specimens Attention should be paid to the conditioning of the timber before the manufacture of the joint and also to the conditioning of the joints as a whole before tes
28、ting. The conditioning should be conducted in such a way that the test conditions correspond in a realistic manner to the conditions in joints in structures as regards the influence of the moisture content on the strength properties of the timber and the occurrence of gaps,etc., through shrinkage. D
29、etailed requirements for specimens made with specific types of fasteners will be given in separate InternationalStandards. 3) Where the purpose of testing is to compare joints under similar conditions, the standard atmosphere20/65 according toISO554 should be used for conditioning. 6 Form and dimens
30、ions of test specimens The test joints shall be of such realistic form and dimensions that the necessary information about the strength and deformation of joints in service can be obtained. Detailed information about the form and dimensions of the test specimens suitable for different types of mecha
31、nical fasteners will be given in separate InternationalStandards. 7 Apparatus In addition to equipment for measuring the geometry of the test specimens, moisture content, etc., the following shall be available: a) a testing machine able to apply and record load with an accuracy of 1% ofF estor bette
32、r; 1) International Council for Building Research, Studies and Documentation. 2) International Union of Testing and Research Laboratories for Materials and Structures. F : applied load, in newtons F est: estimated maximum load, in newtons F max: maximum load, in newtons k : slip modulus, in newtons
33、per millimetre v : joint slip, in millimetres 3) Test methods for joints made with punched metal plate fasteners, nails and staples will form the subject of future InternationalStandards.EN 26891:1991 4 BSI 01-2000 b) equipment to measure joint slip under load with an accuracy of 1% or better, or fo
34、r slips of less than2mm with an accuracy of 0,02mm. The equipment shall ensure that eccentricities, twist, etc. have no influence on the measurements. 4) 8 Loading procedure 8.1 Estimation of maximum load The estimated maximum load, F est , for the type of joint to be tested shall be determined on t
35、he basis of experience, calculation or preliminary tests, and should be adjusted as required in8.6. 8.2 Application of load The loading procedure shown inFigure 1 should generally be followed. The load shall be applied up to0,4F estand maintained for30s. The load shall then be reduced to0,1F estand
36、maintained for30s. Thereafter the load shall be increased until the ultimate load or slip of15mm is reached. 5) Below0,7F esta constant rate of load or slip corresponding to0,2F estper minute 25% shall be used. Above0,7F est , a constant rate of slip shall be used; so adjusted that the ultimate load
37、 or a slip of15mm is reached in3 to5min additional testing time (total testing time about10 to15min). The test may be stopped when the ultimate load is reached, or when the slip is15mm. For particular tests, the preload cycle up to0,4F estmay be omitted with a corresponding adjustment to the total t
38、esting time. 8.3 Measurement of slip The slip measurements v 01 , v 04 , v 14 , v 11 , v 21 , v 24 , v 26andv 28shown inFigure 2 shall be recorded for each test specimen. The slip at maximum load,F max , shall also be recorded. When a load/slip diagram is not available, measurements of slip should b
39、e taken at each0,1F estincrement of load (seeFigure 1). 8.4 Measurement of load The load reached before or at a slip of15mm, shall be recorded as the maximum load,F max , for each specimen. 4) Equipment that can continuously record load and slip is recommended; exceptionally, slips may be measured a
40、t chosen load levels provided the measurements can be made without significantly influencing the continuity of load application. A sufficient number of load levels should be chosen to ensure that the calculations (see8.5) and the adjustments (see8.6) can be made. 5) The requirement that the load be
41、maintained constant for30s at0,4 and0,1F estis to permit adequate time for the loading to be reversed, it is not intended to provide information on creep behaviour. Figure 1 Loading procedureEN 26891:1991 BSI 01-2000 5 8.5 Calculations From the recorded measurements, the following values, if relevan
42、t, shall be determined for each test: If practical, the complete load/slip diagram should also be given. NOTEThe values calculated for9) to12) above relate to the actual value ofF maxfor each of the tests. If a continuous load/slip diagram is available, these values may be obtained directly at the r
43、equired load level. If only readings of slip at increments ofF estare available, the values should be obtained by interpolation. 8.6 Adjustment If, during the execution of the tests, the mean value of the maximum load of the tests already carried out deviates by more than20% from the estimated value
44、,F est , thenF estshould be adjusted correspondingly for subsequent tests. The values of maximum load already determined may be accepted without adjustment as part of the final results. In this case, the values of slip and slip moduli determined in3) to8) of8.5 should be adjusted to correspond to th
45、e adjusted values ofF est . Figure 2 Idealized load-deformation curve and measurements 1) maximum load F max 2) estimated maximum load F est 3) initial slip v i = v 04 4) modified initial slip 5) joint settlement a v s = v i v i,mod 6) elastic slip 7) initial slip modulus k i =0,4F est /v i 8) slip
46、modulus k s =0,4F est /v i,mod 9) slip at0,6F max v 0,6 10) modified slip at0,6F max v 0,6, mod = v 0,6 v 24 + v i, mod 11) slip at0,8F max v 0,8 12) modified slip at0,8F max v 0,8, mod = v 0,8 v 24 + v i, mod a It should be noted that many load-slip curves are initially convex upwards so thatv swil
47、l be negative.EN 26891:1991 6 BSI 01-2000 9 Test report The test report shall include the following information: a) species, density and relevant strength properties of the timber; b) quality, strength properties and surface finish of the materials of the fasteners (including anti-corrosive protecti
48、on); c) dimensions of the joints, size and number of fasteners, details of gaps between members; d) conditioning of timber and test specimens before and after manufacture, moisture content of the timber at manufacture and at test, fissuresetc; e) the loading procedure used (by reference to this Inte
49、rnationalStandard) and a statement of any deviations; f) individual test results and any relevant information regarding adjustments, mean values and standard deviations, and descriptions of the modes of failure.BSEN 26891:1991 BSI 01-2000 National appendix NA (informative) The United Kingdom participation in the preparation of this European Standard was entrusted by the Structural Timber Standards Policy Committee to Technical CommitteeTIB/51 upon which the following bodies were represented: British Timber
