1、December 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 91.080.20!%V-“2595110www.din.deD
2、IN EN 16784Timber structures Test methods Determination of the long term behaviour of coated and uncoated doweltype fasteners;English version EN 16784:2016,English translation of DIN EN 16784:2016-12Holzbauwerke Prfverfahren Bestimmung des Langzeitverhaltens beschichteter und unbeschichteter stiftfr
3、miger Verbindungsmittel;Englische Fassung EN 16784:2016,Englische bersetzung von DIN EN 16784:2016-12Structures en bois Mthodes dessai Dtermination du comportement long terme des lments de fixation de type tige revtus ou non;Version anglaise EN 16784:2016,Traduction anglaise de DIN EN 16784:2016-12w
4、ww.beuth.deDocument comprises 13 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.11.16 DIN EN 16784:2016-12 2 A comma is used as the decimal marker. National foreword This document (EN 16784:2016) has been prepared by Technical
5、 Committee CEN/TC 124 “Timber structures” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was DIN-Normenausschuss Bauwesen (DIN Standards Committee Building and Civil Engineering), Working Committee NA 005-04-01 AA Holzbau (SpA zu CEN/TC 124, CEN/TC 250/SC 5, IS
6、O/TC 165). EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16784 June 2016 ICS 91.080.20 English Version Timber structures - Test methods - Determination of the long term behaviour of coated and uncoated dowel-type fasteners Structures en bois - Mthodes dessai - Dtermination du comportement lon
7、g terme des lments de fixation de type tige revtus ou non Holzbauwerke - Prfverfahren - Bestimmung des Langzeitverhaltens beschichteter und unbeschichteter stiftfrmiger Verbindungsmittel This European Standard was approved by CEN on 8 April 2016. CEN members are bound to comply with the CEN/CENELEC
8、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 may be obtained on application to the CEN-CENELEC Management Centre or to
9、 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-CENELEC Management Centre has the same status as the officia
10、l versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, No
11、rway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exp
12、loitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16784:2016 E2 Contents Page European foreword . 3 1 Scope 4 2 Normative references 4 3 Terms and definitions . 4 4 Symbols and abbreviations . 4 5 Sampling . 5 5.1 Timber . 5 5.2 Fasteners 5 6 Test method
13、 6 6.1 General 6 6.2 Conditioning 6 6.3 Fabrication of the specimens 6 6.3.1 Fastener axis perpendicular to the grain . 6 6.3.2 Fastener axis parallel to the grain 6 6.4 Test procedure . 7 6.5 Testing for duration of withdrawal load 8 7 Expression of the results 8 7.1 Load duration factor for withdr
14、awal . 8 7.2 Test report . 9 Bibliography . 11 EN 16784:2016 (E) DIN EN 16784:2016-12 3 European foreword This document (EN 16784:2016) has been prepared by Technical Committee CEN/TC 124 “Timber Structures”, the secretariat of which is held by AFNOR. This European Standard shall be given the status
15、 of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2016, and conflicting national standards shall be withdrawn at the latest by December 2016. Attention is drawn to the possibility that some of the elements of this document may be the sub
16、ject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, B
17、ulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, 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,
18、 Turkey and the United Kingdom. EN 16784:2016 (E) DIN EN 16784:2016-12 4 1 Scope This European Standard specifies a test method for the determination of the long duration withdrawal strength of coated and uncoated dowel-type fasteners in structural timber and timber products and wood based products
19、for structural application. The method applies to all types of nails, screws and staples. 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.
20、For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1382, Timber Structures Test methods Withdrawal capacity of timber fasteners EN 26891:1991, Timber structures Joints made with mechanical fasteners General principles for the determination of
21、 strength and deformation characteristics (ISO 6891:1983) EN ISO 8970, Timber structures Testing of joints made with mechanical fasteners Requirements for wood density (ISO 8970) ISO 13061-1, Physical and mechanical properties of wood Test methods for small clear wood specimens Part 1: Determination
22、 of moisture content for physical and mechanical tests ISO 13061-2, Physical and mechanical properties of wood Test methods for small clear wood specimens Part 2: Determination of density for physical and mechanical tests 3 Terms and definitions For the purposes of this document, the following terms
23、 and definitions apply. 3.1 reference withdrawal strength mean (50 % fractile) withdrawal strength of the tests carried out in accordance with EN 1382 3.2 load level percentage of the reference withdrawal strength 4 Symbols and abbreviations a staple crown width, in millimetres (see Figure 1) d is t
24、he outer thread diameter for screws, the diameter of the smooth plain part of a round nail or for staples the diameter of the wire (transformed to a round cross-section) (see EN 14592) Fmaxmaximum withdrawal load, in newtons kd,Tduration of load factor for withdrawal load lpthe effective depth of pe
25、netration of fastener, in millimetres. For smooth nails and staples this includes the point. For profiled nails and screws only the penetration depth of the profiled part. In the case of partly or completely resin coated fasteners only the depth of penetration of the coated part.EN 16784:2016 (E) DI
26、N EN 16784:2016-12 5 crnangle between the direction of a staple crown and the grain direction or the main direction of the timber or wood based products, respectively, in degrees (see Figure 2) Tfelapsed time to failure in minutes for a certain test specimen T time to failure Figure 1 Staple dimensi
27、ons Figure 2 Angle between the staple direction and the grain direction 5 Sampling 5.1 Timber The range of density of the test pieces shall be representative of the density of the mechanical class or range of product to which they belong. The sampling of test pieces shall be done in accordance with
28、EN ISO 8970. 5.2 Fasteners The technical specification of the nails, screws and staples shall be established. EN 16784:2016 (E) DIN EN 16784:2016-12 6 6 Test method 6.1 General The moisture content and density of the timber at test shall be determined as specified in ISO 13061-1 and ISO 13061-2 as a
29、ppropriate. 6.2 Conditioning The test pieces shall be manufactured with the timber products at an equilibrium moisture content corresponding to (20 2) C and (80 5) % relative humidity. The material is conditioned when it attains constant mass. Constant mass is considered to be attained when the resu
30、lts of two successive weightings, carried out at an interval of 6 h, do not differ by more than 0,1 % of the mass of the material. For certain investigations, other moisture conditioning can be appropriate and shall be reported. NOTE The high moisture content reflects the worst design situation wher
31、e wet timber is installed that dries out in service. 6.3 Fabrication of the specimens 6.3.1 Fastener axis perpendicular to the grain The axis of the fastener shall be perpendicular to the timber surface. The insertion of fasteners shall follow normal preparation (e.g. pre-boring) and practice. The p
32、osition of the fastener is such that no eccentricities occur in transferring the load to the timber. The width and depth of the test piece in the direction of insertion of the fastener shall be equal and at least lp + 5d for nails and screws (see Figure 3), and for staples at least 10d. Where the te
33、st pieces are of solid timber or glued laminated timber, the fasteners shall be inserted irrespective of the direction of the growth rings. In addition for staples, half of the tests shall be carried out with crn = 0 and the other half with crn = 90. Figure 3 Withdrawal test pieces - load perpendicu
34、lar to grain 6.3.2 Fastener axis parallel to the grain The test piece shall comply with Figure 4. The fastener shall be driven into the end grain to a penetration of between 8d and 20d and shall be positioned in the centre line of the timber specimen as to prevent any eccentricities in the load tran
35、sfer. A depth of penetration of at least 12d is appropriate to fasteners of d less than 2 mm. EN 16784:2016 (E) DIN EN 16784:2016-12 7 NOTE The range of depth penetration is given so that the depth of penetration used in the test can be decided depending on the withdrawal resistance EN 1382 and the
36、tensile capacity of the fastener. The cross-sectional dimensions of the test piece shall be equal and at least 10d (see Figure 4). For staples, the dimensions parallel and perpendicular to the crown shall be equal and at least 6a and 4a, respectively (see Figure 4). The test piece dimension parallel
37、 to grain shall be at least 2lp + 5d for nails and screws, and for staples at least 2lp + 3a. Figure 4 Withdrawal test pieces - load parallel to grain 6.4 Test procedure The apparatus used shall be as required in EN 26891:1991, Clause 7. Tests are carried out in an environment corresponding to (20 2
38、) C and (65 5) % relative humidity. If these conditions are not maintained during the test, they shall be reported. Test of thermo plastic adhesive coatings shall be performed at elevated temperatures. NOTE 1 The design rules in EN 1995-1-1 are valid up to 60 C. Determine the depth of the fastener p
39、enetration lp. Place the test specimen in a device ensuring the application of the withdrawal force along the axis of the fastener or the axes of the staple legs. Any part of the supports that hold the timber test specimen shall be not closer to the axis of the fastener than 3d for nails and screws
40、and a for staple. The loading procedure is in accordance with EN 26891 were the load shall be applied with constant increments until the required load level is attained. The required load is held constant until failure or termination of the test. The time to failure or termination of the test shall
41、be recorded. NOTE 2 Usually the test specimens are mounted in strings in a rig and loaded by dead load. To keep the dead load within limits a level arm can be applied. It is important that the lever arm can function with or without negligible friction at the hinges. EN 16784:2016 (E) DIN EN 16784:20
42、16-12 8 6.5 Testing for duration of withdrawal load To determine the load duration withdrawal factor at least 10 test specimens are loaded to at least two of the following load levels: 20 %, 30 %, 40 %, 55 %, 60 %, 65 %, 70 %, or 80 % of the reference withdrawal strength. NOTE Best practice is to ch
43、oose very different load levels appropriate to the aim of the test. The reference withdrawal strength is the mean (50 % fractile) of the withdrawal strength established by tests in accordance with EN 1382. For the reference withdrawal strength perpendicular to grain the average of the withdrawal str
44、ength in radial and tangential direction is taken. If these tests were carried out with the insertion direction at random with respect to the radial and tangential direction the resulting mean withdrawal strength can directly be taken as reference withdrawal strength. If test specimens fail during t
45、he initial loading, this load level shall be discarded from the investigation. For all tests, record the time to failure in minutes expressed to the nearest 1% of the elapsed time, Tf. The tests shall continue until at least 7 test specimens at each load level have failed. 7 Expression of the result
46、s 7.1 Load duration factor for withdrawal The load duration for withdrawal at a given time is defined as the ratio of the load level that results in failure at that time, to the mean reference withdrawal strength. The load duration factor for withdrawal, kd,Tshall be determined by plotting the load
47、level against log10time (T) to failure. Calculate the mean time to failure at each load level for those test specimens which have failed. Calculate the linear regression line treating the load level as the independent variable, to provide Formula (1) of the form: = LogT c mLL (1) where c is the inte
48、rcept on the vertical axis; m is the slope; LL is the load level, in percent; T is the time to failure, in minutes. Formula (1) is then rearranged algebraically to give the more traditional form: d,TlogLL = e - f T = k (2) where ce=m1f=m(3) EN 16784:2016 (E) DIN EN 16784:2016-12 9 The extrapolated l
49、oad level for a particular life is then calculated using Formula (2) and expressed to three significant figures. An example for a ten year life (log T= 6,72) is illustrated in Figure 5. Key X is log time Y is the load level Figure 5 Example of a load duration regression curve The symbol, kd,Tshall embrace the time of loading and the service class to which it applies. NOTE An example of a predicted kd,T value at 10 years calculat
