1、 Reference number ISO 12579:2007(E) ISO 2007INTERNATIONAL STANDARD ISO 12579 First edition 2007-10-01 Timber structures Glued laminated timber Method of test for shear strength of glue lines Structures en bois Bois lamell-coll Mthode dessai de cisaillement des plans de collage ISO 12579:2007(E) PDF
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6、Os member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007 All rights reservedISO 12579:2007(E) ISO 2007 All rights reserved iiiConten
7、ts Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Symbols and abbreviated terms . 2 5 Principle. 2 6 Test samples and test specimens. 2 6.1 Test samples . 2 6.2 Test specimens . 3 6.3 Alternative test specimens 4 6.4 Adjustments to results for alt
8、ernative test specimens. 5 6.5 Rectangular-prism test specimens from wide glulam timber members. 5 7 Apparatus 6 7.1 Testing machine 6 7.2 Shearing apparatus 6 8 Procedure 7 9 Results . 7 9.1 Calculation of shear stress 7 9.2 Test report . 8 ISO 12579:2007(E) iv ISO 2007 All rights reservedForeword
9、ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical
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12、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 possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for ident
13、ifying any or all such patent rights. ISO 12579 was prepared by Technical Committee ISO/TC 165, Timber structures. ISO 12579:2007(E) ISO 2007 All rights reserved vIntroduction This International Standard was developed by TC 165 as a production quality-control test to be used for structural glulam. I
14、t is meant to be used in conjunction with ISO 12578 and to be applied to each production batch. The frequency of testing and the pass/fail criteria are detailed in ISO 12578. There is nothing, in principle, that would prevent the test method from being applied to non-structural glulam. INTERNATIONAL
15、 STANDARD ISO 12579:2007(E) ISO 2007 All rights reserved 1Timber structures Glued laminated timber Method of test for shear strength of glue lines 1 Scope This International Standard specifies a production quality-control test method for measuring the shear strength of the glue line of glued laminat
16、ed timber. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 12578, Timb
17、er structures Glued laminated timber Component performance and production requirements 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 glued laminated timber glulam structural member formed by bonding together timber laminations with the grai
18、n running essentially parallel 3.2 test sample one or more test specimens taken from a press load or production lot detailed in ISO 12578 3.3 test specimen test piece of rectangular prismatic or cylindrical form See Figures 2 to 5. 3.4 wood failure rupture in or between wood fibres 3.5 wood-failure
19、percentage percentage of the wood-failure area in relation to the total sheared area ISO 12579:2007(E) 2 ISO 2007 All rights reserved4 Symbols and abbreviated terms A: area, in square millimetres; b: width of test specimen, in millimetres; d: diameter of cylindrical cored specimen, in millimetres; F
20、 u : ultimate load, in newtons; f s : shear strength, in newtons per square millimetre; l: length of test specimen, in millimetres; s: step height in a stepped rectangular-prism specimen, in millimetres; t: thickness of shear plane, in millimetres; w: full width of glulam timber member, in millimetr
21、es. 5 Principle A shear stress is applied at the glue line until failure occurs. The load at failure is recorded and the wood-failure percentage is evaluated. 6 Test samples and test specimens 6.1 Test samples Test samples shall be taken from production at a sampling rate detailed in ISO 12578. One
22、or more test specimens shall be taken from the glued laminated timber member as illustrated in Figure 1. NOTE Rectangular-prism specimens from wider members can require a reduction in width to fit into the shearing apparatus. See also 6.5 and Figure 6. It is recommended that the specimens be taken w
23、ithin areas of the glulam member where sufficient clamping pressure has been established. In practice, the specimens are frequently cut from the end of the glulam members where the clamping pressure may be variable and insufficient. If the required shear strength is obtained from test pieces of this
24、 nature, the quality of the glue lines in the member shall be deemed adequate. ISO 12579:2007(E) ISO 2007 All rights reserved 3a) Narrow beams b) Wide beams Key 1 cut cylindrical specimen clear of the manufactured end 2 cut rectangular specimen clear of the manufactured end Figure 1 Sampling from gl
25、ued laminated members 6.2 Test specimens The standard test specimen shall be the rectangular-prism specimen shown in Figure 2. The width, b, and thickness, t, of the shear plane shall be a nominal 50 mm. Actual dimensions shall be measured for each shear plane tested. The specimen length, l, is not
26、critical. Alternative test specimens shall be permitted in accordance with 6.3. Special care shall be taken in preparing the test specimens to ensure that the loaded surfaces are smooth and parallel to each other and perpendicular to the grain direction. At least three glue lines in each of the top
27、one-third, center one-third, and bottom one-third of the cross-section shall be included in the sampling. If there are fewer than 10 laminations, all glue lines shall be included. Figure 2 Standard rectangular-prism specimen ISO 12579:2007(E) 4 ISO 2007 All rights reserved6.3 Alternative test specim
28、ens Alternative test-specimen configurations or sizes shall be permitted, provided that the test results from the alternative specimen are correlated to test results of the standard rectangular-prism specimen according to 6.4. Common configurations for alternative specimens include stepped rectangul
29、ar-prism specimens (Figure 3), cylindrical specimens (Figure 4), and rectangular-prism specimens with saw kerfs (Figure 5). Cylindrical specimens typically have a diameter of 25 mm. For rectangular-prism and stepped rectangular- prism specimens, common shear-plane dimensions, b and t, range from 25
30、to 50 mm. Step heights, s, for stepped rectangular-prism specimens are typically approximately 5 mm. Figure 3 Stepped rectangular-prism specimen Figure 4 Cylindrical test specimen ISO 12579:2007(E) ISO 2007 All rights reserved 5Figure 5 Rectangular-prism specimen with saw kerfs 6.4 Adjustments to re
31、sults for alternative test specimens The values obtained from tests of rectangular-prism specimens shall be considered standard. When using alternative specimens, a regression between the shear values obtained using the alternative specimen and the shear values obtained using the rectangular-prism s
32、pecimen shall be established using a minimum of 20 tests of each specimen type. Matching specimens shall be taken from the same piece of glulam, as close to one another as cutting conditions permit. The regression equation shall be used to adjust the test values of the alternative specimen to an equ
33、ivalent rectangular-prism result. 6.5 Rectangular-prism test specimens from wide glulam timber members Depending on the width of the glulam timber member, multiple specimens shall be cut in accordance with the details given in Table 1. Where such multiple specimens are taken, a full cross-section sh
34、all first be cut and then subdivided by vertical cuts as illustrated in Figure 6. Table 1 Number of test specimens from wide glulam timber members Width, w, of full cross-section (see Figure 1) mm Number of test specimens u 100 100 u 160 160 1 2 3 ISO 12579:2007(E) 6 ISO 2007 All rights reservedDime
35、nsions in millimetres Key 1 saw cut Figure 6 Test specimens to be cut from a full cross-section of a glulam member 7 Apparatus 7.1 Testing machine A calibrated testing machine shall be used that is capable of applying a compressive shear force to the shearing apparatus referred to in 7.2. The accura
36、cy of measuring the maximum load shall be better than 5 %. 7.2 Shearing apparatus The shearing apparatus shall be capable of applying a shear force in the plane of the glue line as illustrated in Figure 7. ISO 12579:2007(E) ISO 2007 All rights reserved 7a) Front view b) Side view Key 1 cylindrical s
37、elf-aligning platen 2 sheared plane and bond line 3 test specimen to be clamped as necessary 4 grain direction 5 shearing apparatus Figure 7 Method of applying shear load to a glue line 8 Procedure The test specimens shall be tested in an environment typical of the production conditions. For interna
38、l quality control, the moisture content of the wood shall correspond to that used in the production of the glulam. The dimensions b and t of the sheared area shall be measured to the nearest 0,5 mm. The test specimen shall be placed in the shearing tool so that it is loaded in the direction of the g
39、rain. The glue line shall be positioned so that the distance between this and the sheared plane nowhere exceeds 1 mm. The loading shall be undertaken at a constant rate, so that failure occurs after at least 20 s. The percentage of wood-failure shall be estimated to the nearest 5 %. Every test speci
40、men shall be marked with a durable identification. This shall indicate the location of the test specimen within the cross-section of the glulam member. 9 Results 9.1 Calculation of shear stress The shear strength f sshall be computed to two significant digits from the following equation: u s F f A =
41、 where F uis the ultimate load, in newtons; A is the sheared area, in square milllimetres (for a rectangular-prism test specimen A = bt). ISO 12579:2007(E) 8 ISO 2007 All rights reserved9.2 Test report The test report shall include the following items: a) date of the test; b) description of the prod
42、uct; c) identification of test specimens and their location in the member; d) species of timber; e) type of adhesive; f) dimensions and configuration of the test specimen; g) ultimate load and shear strength; h) regression equation used to adjust test values to standard values; i) wood-failure percentage; j) signature of the person responsible for the testing. ISO 12579:2007(E) ICS 91.080.20 Price based on 8 pages ISO 2007 All rights reserved
