1、CEN ENWb891, 91 3404589 0015358 I, =I p_ - _ EUROPE ANZANDARD NORME EUROPENNE EUROPISCHE NORM February 1991 UDC 694.14 : 624.011.1 : 624.042/044 : 621.882 Descriptors: Timber construction, joining, fasteners, characteristics, mechanicai strength, deformation, loading English version Timber structure
2、s - Joints made with mechanical fasteners - General principles for the determination of strength and deformation characteristics (IS0 6891 : 1983) Structures en bois - Assemblages raliss avec des lments mcaniques de fixation - Principes gnraux pour la dtermination des caractristiques de rsistance et
3、 de dformation (IS0 6891 : 1983) (IS0 6891 : 1983) Holzbauwerke - Verbindungen mit mechanischen Verbindungsmitteln - Allgemeine Grundstze fr die Ermittlung der Tragfhigkeit und des Verformungsverhaltens This European Standard was approved by CEN on 17 January 1991 and is identical to the IS0 standar
4、d as referred to. CEN members are bound to comply with the CENICENELEG 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 national standards ma
5、y 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 notified to the Cen
6、tral 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 United Kingdom. CEN European
7、 Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1060 Brussels O CEN 1991 Copyright reserved to all CEN members Ref. No. EN 26891 : 1991 E . I CEN EN*k2bdqL 91 3404589 0015359 3 W Page 2 i EN 26891 : 1991 I Forewo
8、rd Based on the positive result of the Primary Questionnaire procedure, the Echnical Board decided by Resolution EYi 321/1989 to submit the International Standard IS0 6891 : 1983 “Timber structures - Joints made with mechanical fasteners - General principles for the determination of strength and def
9、ormation characteristics to the formal vote. me result was positive. In accordance with the CENKENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemburg, Netherl
10、ands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard IS0 6891 : 1983 was approved by CEN as a European Standard without any modification. CEN EN*Zb893 93 W 3404589 0035360 T W: L r- - Page 3 EN 26891 : 1991 Timber struct
11、ures - Joints made with mechanical fastenkrs - General principles for the determination of strength and deformation characteristics O Introduction Developments in the field of load-bearing timber structures re- quire that joints made with mechanical fasteners be tested to obtain information about th
12、eir 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 out in different laboratories. Stan- dard rules for the determination of characteristic stre
13、ngths for particular types of mechanical fasteners will be given in separate International Standards, This International Standard is based on Joint Recommenda- tions from Working commission W18, Timber Structures, of GIB) and Committee 3TT, Timber Testing, of RILEM2), who will also prepare the basis
14、 for the above-mentioned supplemen- tary International Standards, 1 Scope This International Standard lays down general principles for the determination of the strength and deformation (slip) charac- teristics of joints made with mechanical fasteners. 2 Field of application This International Standa
15、rd is applicable to joints made with mechanical fasteners used in statically loaded timber struc- tures. Detailed procedures appropriate to joints made with specific fasteners will be given in separate International Standards . The principles can also be used for the testing of other joints. It is r
16、ecognized that for some special types of joints not covered by International Standards, modification of the test procedure may be necessary. 3 Reference IS0 554, Standard atmospheres for conditioning and/or testing - Specifications. 11 International Council for Building Research, Studies and Documen
17、tation, 2) International Union of Testing and Research Laboratories for Materials and Structures. CEN EN*Zb891 91 - - - Page 4 EN 26891 : 1991 3404589 00153bL II W 4 Symbols F : applied load, in newtons Fest : estimated maximum load, in newtons F, : maximum load, in newtons k : slip modulus, in newt
18、ons per millimetre b) equipment to measure joint slip under load with an ac- curacy of f 1 % or better, or for slips of less than 2 mm with an accuracy of f 0,02 mm. The equipment shall en- sure that eccentricities, twist, etc. have no influence on the measurements.*) 8 Loading procedure v : Subscri
19、pts for the joint slip, v, relate to load points in figure 2 and are defined in clause 8. joint slip, in millimetres 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 b
20、efore testing. The conditioning should be conducted in such a way that the test conditions correspond in a realistic manner to the condi- tions 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
21、shrinkage. Detailed requirements for specimens made with specific types of fasteners will be given in separate International Standards.1) Where the purpose of testing is to compare joints under similar conditions, the standard atmosphere 20165 according to IS0 554 should be used for conditioning. 6
22、Form and dimensions of test specimens The test joints shall be of such realistic form and dimensions that the necessary information about the strength and defor- mation of joints in service can be obtained. Detailed information about the form and dimensions of the test specimens suitable for differe
23、nt types of mechanical fasteners will be given in separate International Standards. 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
24、 f 1 % of Fest or better; 8.1 Estimation of maximum load The estimated maximum load, Fat, for the type of joint to be tested shall be determined on the basis of experience, calcula- tion or preliminary tests, and should be adjusted as required in 8.6. 8.2 Application of load The loading procedure sh
25、own in figure 1 should generally be followed. The load shall be applied up to 0,4 Fest and maintained for 30 s. The load shall then be reduced to 0,l Fest and maintained for 30 s. Thereafter the load shall be increased until the ultimate load or slip of 15 mm is reached.3) Below 0,7 Fat a constant r
26、ate of load or slip corresponding to 0,2 Fest per minute i 25 % shall be used,Above 0,7 Fest, a constant rate of slip shall be used; so adjusted that the ultimate load or a slip of 15 mm is reached in 3 to 5 min additional testing time (total testing time about 10 to 15 min). The test may be stopped
27、 when the ultimate load is reached, or when the slip is 15 mm. For particular tests, the preload cycle up to 0,4 Fest may be omitted with a corresponding adjustment to the total testing time. 8.3 Measurement of slip The slip measurements vol, vo4, 14, vil, v, 24, v, and vB shown in figure 2 shall be
28、 recorded for each test specimen. The slip at maximum load, Fmax, shall also be recorded. When a load/slip diagram is not available, measurements of slip should be taken at each 0,l Fest increment of load (see figure 1). 8.4 Measurement of load The load reached before or at a slip of 15 mm, shall be
29、 recorded as the maximum load, Fmax, for each specimen. 1) Test methods for joints made with punched metal plate fasteners, nails and staples will form the subject of future International Standards. 2) Equipment that can continuously record load and slip is recommended; exceptionally, slips may be m
30、easured at 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 (see 8.5) and the adjustments (see 8.6) can be made. 3) The requirement that t
31、he load be maintained constant for 30 sat 0,4 and O, 1 Fest is to permit adequate time for the loading to be reversed, it is not intended to provide information on creep behaviour. CEN EN*Zb89L 91 E 3404589 0035362 3 E - Page 5 EN 26891 : 1991 Figure 1- Loading .procedure O Joint slip, v Figure 2 -
32、Idealized load-deformation curve and measurements i Page 6 EN 26891 : 1991 CEN EN*Zbi1 8.5 Calculations From the recorded measurements, the following values, if rele- vant, shall be determined for each test : 1) maximum load Fmax 2) estimated maximum load Fest 3) initial slip yi = v(J4 4 3 4) modifi
33、ed initial slip V,od =-(va - vol) 5) joint settlementi) v, = - q,mod 2 3 6) elastic slip ve =-(vi4 + 24 - vi1 - 21) 7) initial slip modulus ki = 0,4 Festlvi 8) slip modulus ks = 0,4Fest/yi,mod 9) slip at 0,6 Fmax v0,6 IO) modified slip at Ot6 Fmax v0,6, mod = v0,6 - v24 -k q, mod 11) slip at 0,8 Fma
34、x v0,8 12) modified slip at Ot8 “0,8, mod = v0,8 - v24 i- 9, mod If practical, the complete loadlslip diagram should also be given. NOTE - The values calculated for 9) to 12) above relate to the actual value of Fmax for each of the tests. If a continuous load/slip diagram is available, these values
35、may be obtained directly at the required load level. If only readings of slip at increments of Fest are 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 mor
36、e than 20 % from the estimated value, Fest, then FWt should 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 in 3) to 8) of 8.5
37、should be ad- justed to correspond to the adjusted values of Fest. 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 (includi
38、ng anti-corrosive protec- tion); 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, fissures etc; e) national Standard) and a
39、 statement of any deviations; f) individual test results and any relevant information regarding adjustments, mean values and standard devia- tions, and descriptions of the modes of failure. the loading procedure used (by reference to this Inter- 1) It should be noted that many load-slip curves are initially convex upwards so that vs will be negative.
