1、STD=BSI BS EN L288-3-ENGL 2000 W Lb24bb9 OBb BRITISH STANDARD - 108 235 W BS EN 1288-3:2000 Glass in building - Determination of the bending strength of glass - Part 3: Test with specimen supported at two points (four point bending) The European Standard EN 12883:2000 has the status of a British Sta
2、ndard ICs 81.040.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYBIGHT LAW _ STDmBSI BS EN 1288-3-ENGL 2000 D Lb24bb9 0867309 173 direction of the Sector Committee for Budding and Civil Engineering, was published under the authorily of the Standards Committee and comes into effect on
3、 15 August 2000 Amd. No. 0 BSI 082000 BS EN 128 - present to the responsible European committee any enquiries on the - monitor related international and European developments and promulgate interpretation, or proposals for change, and keep the UK interests informed; them in the UK A list of oqpnhati
4、ons represented on this subcommittee can be obtained on request to its secretaq. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “Inkrnational Standards C
5、orrespondence Index“, or by using the Find“ facility of the BSI Standards Electronic Catalogue. 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
6、 not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 11 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. ISBN o 580 a6152 7
7、 EUROPEAN STANDARD NORME EUROPENNE EUROPASCHE NORM m lb24bb O8b7110 i93 m EN 12883 June 2000 ICs 81.040.20 English version Glass in building - Determination of the bending strength of glass - Part 3: Test with specimen supported at two points (four point bending) Verre dans la construction - Dtermin
8、ation de la rsistance du verre la flexion - Partie 3: Essais avec prouvettes supportes en deux points (flexion quatre points) Glas im Bauwesen - Bestimmung der Biegefestigkeit von Glas - Teil 3: Prfung von Proben bei zweiseitiger Auflagerung (Vierschneiden-Verfahren) This European Standard was appro
9、ved by CEN on 5 September 1999. CEN members are bound to comply with the CENKENELEC Intemal Regulations which stipulate the conditions for giving this Europein Standard the status of a national standard without any alteration. Up-todate lists and bibliographical references concerning such national s
10、tandards 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 traislation under the responsibility of a CEN member into its own language and notified
11、 to the Central Secretariat has the same status as fie official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and U
12、nited Kingdom. EUROPEAN COMMITEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Centrai Secretariat: rue de Stassart, 36 8-1050 Brussels Q 2000 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1288
13、-3:2000 E Page 2 EN 1288-3:2000 Contents Page Foreword 3 1 Scope 4 . 2 Normative references 4 . 3 Definitions. 4 Sym bo 1s 5 4 5 6 7 Apparatus 6 5.1 Testing machine . 6 5.2 Measuring instruments . 6 Sample 6 6 6.1 Number of specimens 6 6.2 Specimen dimensions 6.3 6.4 Adhesive film 7 . Specimen condi
14、tion and treatment. 7 Procedure 7 7.1 Measuring width and thickness of each specimen . 7 7.2 Bending test . 8 8 Evaluation . 8 8.1 General 8.2 8.3 Bending strength of the surface area, edges included . 9 Bending strength of the edges . 9 Test report . 10 8 BSI O-2000 STDaBSI BS EN 1288-3-ENGL 2000 =
15、 1h24hb9 0867112 766 H Page 3 EN 1288-312000 Foreword This European Standard has been prepared by Technical Committee CEN/TC 129, Glass in building, the Secretariat of which is held by IBN. This European Standard shall be given the status of a national standard, either by publication of an identical
16、 text or by endorsement, at the latest by December 2000, and conflicting national standards shall be withdrawn at the latest by December 2000. CEN/TC 129MIG8, Mechanical Strength, prepared the draft, Glass in building - Determination of the bending strength of glass - Part 3: Test with specimen supp
17、orted at two points (four point bending). There are four other parts to this standard: - Part 1 : Fundamentals of testing glass; - Part 2: Coaxial double ring test on flat specimens with large test surface areas; - Part 4: Testing of channel shaped glass; - Part 5: Coaxial double ring test on flat s
18、pecimens with small test surface areas. According to the CENICENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Ita
19、ly, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. O BSI 08-2000 Page 4 EN 1288-312000 1 Scope This European Standard specifies a method for determining the bending strength, including the effects of the edges, of flat glass for use in building. The met
20、hod specified can also be used to determine the bending strength of the edges of glass separately. The limitations of this standard are described in EN 1288-1. EN 1288-1 should be read in conjunction with this standard. 2 Normative references This European Standard incorporates by dated or undated r
21、eference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incor
22、porated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. EN 572-1 EN 1288-1 IS0 48 Glass in building - Basic soda lime silicate glass products - Part 1: Definitions and general physical and mechanical properties. Glass in building - D
23、etermination of the bending strength of glass - Part 1: Fundamentals of testing glass. Rubber, vulcanized or thermoplastic - Determination of hardness (hardness between 10 IRHD and 100 IRHD). 3 Definitions For the purposes of this standard, the following definitions apply. 3.1 3.2 3.3 3.4 bending st
24、ress: the tensile bending stress induced in the surface of a specimen NOTE: For testing purposes, the bending stress should be uniform over a specified part of the surface. effective bending stress: a weighted average of the tensile bending stresses, calculated by applying a factor to take into acco
25、unt non-uniformity of the stress field bending strength: the bending stress or effective bending stress which leads to breakage of the specimen equivalent bending strength: the apparent bending strength of patterned glass, for which the irregularities in the thickness do not allow precise calculatio
26、n of the bending stress Q BSI 08-2000 4 3 E Fman g h k L LS Lb Mb Y Z Ob Obeff ObB ObG P Page 5 EN 1288-312000 Symbols Specimen width Modulus of elasticity (Youngs modulus) of the specimen NOTE: For soda lime silicate glass (see EN 572-I), a value of 70 x Id N/mm2 is used. Maximum force NOTE: Where
27、the bending rollers are not firmly attached to the testing machine, but are laid on the specimen, the force resulting from their weight is added to the maximum measured force. Acceleration due to gravity Specimen thickness Dimensionless factor (see 6.2 of EN 1288-1 for explanation) Specimen length D
28、istance between the centre lines of the supporting rollers Distance between the centre lines of the bending rollers Bending moment Central deflection of the specimen relative to the supporting rollers Section modulus Bending stress in the surface area defined by the bending rollers Effective bending
29、 stress Bending strength Bending stress imposed by the self-weight of the specimen Density of the specimen O BSI 08-2000 STD-BSI BS EN 1288-3-ENGL 2000 1b24bb9 OBb7l115 475 m Page 6 EN 1288-3:2000 5 Apparatus 5.1 Testing machine The bending test shall be carried out using a suitable bending testing
30、machine, which shall incorporate the following features. a) The stressing of the specimen shall be capable of being applied from zero up to a maximum value in a manner which minimizes shock and is stepless. b) The stressing device shall be capable of the specified rate of stressing. c) The testing m
31、achine shall incorporate a load measuring device with a limit of error of 12,0 % within the measuring range. d) The supporting rollers and the bending rollers (see Figure 2) shall have a diameter of 50 mm and a length of not less than 365 mm. All the rollers shall be free to rotate. 5.2 Measuring in
32、struments The following measuring instruments are required: - a measuring instrument enabling the width of the specimen to be measured to the nearest millimetre; - a measuring instrument allowing the thickness of the specimen to be measured to the nearest 0,Ol mm. 6 Sample 6.1 Number of specimens Th
33、e number of specimens to be tested shall be determined depending on the confidence limits required, especially with regard to estimating the extremes of the strength distribution (see EN 1288-1 for a discussion of numbers of specimens). 6.2 Specimen dimensions Specimen length, L: 1100mm5mm Specimen
34、width, B: 360 mm f 5 mm Specimen thickness, h: thickness of the glass within the tolerance specified for the condition as supplied for test. Q BSI 08-2000 Page 7 EN 1288-3:2000 6.3 Specimen condition and treatment The specimens shall be flat and their edges shall be representative of the edge finish
35、 to be tested. If the edge is asymmetrical with respect to the neutral axis of the specimen, both stressed edges shall be in the same orientation (see Figure 1) and all specimens in a sample shall be tested the same way up. 1 r I II correct incorrect I Wheel cut edges NOTE: The edges of cut glass ar
36、e not the same on both corners because wheel cut edges have the wheel applied to only one surface of the glass. In this instance, the edge are asymmetrical with respect to the neutral axis of the specimen. Figure I : Asymmetrical edges Any intended changes to the condition of the test piece by means
37、 of edge working, prior mechanical damage, etching, etc., shall be completed at least 24 h before testing the bending strength (see EN 1288-1). Similarly, protective coatings shall be removed at least 24 h before the test. The specimens shall be stored in the testing environment (see 7.2) for at lea
38、st 4 h before being tested. 6.4 Adhesive film To hold together the fragments, an adhesive film shall be fixed to the side of the specimens facing the bending rollers (see Figure 2). This facilitates location of the fracture origin and measurement of the specimen thickness. 7 Procedure 7.1 Measuring
39、width and thickness of each specimen The width shall be determined as the arithmetic mean of at least three individual measurements. The thickness shall be determined as the arithmetic mean of at least four individual measurements to the nearest 0,05 mm. The measured positions shall lie outside the
40、two bending rollers, to avoid damaging the test surface, and shall be taken from both ends of the specimen. In the case of specimens with one or two ornamental surfaces, both the plate thickness and core thickness shall be measured. The average is taken from all these measured values . O BSI 08-2000
41、 Page 8 EN 1288-312000 Alternatively, the thickness shall be determined from at least four fragments taken from the area between the bending rollers after fracture, if the fracture pattern makes this feasible. h I, 1 Specimen 2 Bending roller 3 . Supporting roller 4 Rubber strips Lb = 200 mm f I mm
42、Ls = 1000mmf2mm Figure 2: Mounting of the test specimen 7.2 Bending test The specimen shall be mounted as shown in Figure 2. Strips of rubber, 3 mm thick and of hardness (40 f IO) IRHD (in accordance with IS0 48), shall be placed between the specimen and the bending and supporting rollers. The bendi
43、ng test shall be carried out at (23 f 5) OC with the relative humidity between 40 % and 70 %. During the test, the temperature shall be kept constant to 1 OC, in order to avoid the development of thermal stresses. The specimen shall be bent with a uniformly increasing bending stress at a rate of (2
44、f 0,4) N/mm2-s until failure occurs. The maximum load, Fmm, shall be measured and the time taken to reach this load shall be recorded. 8 Evaluation 8.1 General For evaluation purposes, only those specimens shall be considered in which the origin of fracture lies between the bending rollers. The bend
45、ing strength, obBi shall be calculated in accordance with equation (1) as follows. Q BSI 08-2000 STDmBSI BS EN 1288-3-ENGL 2000 M 1624hh9 08h7LLB 184 Page 9 EN 1288-312000 For a rectangular cross-section, where Z = Bh2/6, and with the load applied as shown in Figure 2, the bending strength is: The b
46、ending stress, UbG, imposed by the self-weight of the specimen shall be calculated in accordance with equation (2): 8.2 Bending strength of the surface area, edges included For calculating the overall bending strength or equivalent bending strength of the surface area, including the edges, defined b
47、y the bending rollers, the value k = ks = 1 shall be used (see EN 1288-1). 8.3 Bending strength of the edges For calculating the bending strength or equivalent bending strength of the free edges of the glass, only those specimens which fracture from the edge shall be taken into consideration. NOTE:
48、When some of the specimens do not break from the edge, the set of edge strength results is not a true representation of the distribution of edge strengths. The edge strengths of those specimens which fracture from the test surface cannot be determined, but they are certainly higher than the measured
49、 values of bending strength of such specimens. There are, however, statistical techniques which can make an allowance for the unmeasured edge strength of those specimens. The factor k = ke for use in equation (1) depends on the deflection of the specimen at its centre. The central deflection, y, can be determined by direct measurement, or calculated with sufficient accuracy from equation (3): The appropriate value of kel for use in equation (I), shall be obtained from Figure 3, which gives the value of ke as a function of the value of y/h (see EN 1288
