© ISO 2016 Timber structures — Determination of characteristic values — Part 3 Glued laminated timber Structures en bois — Détermination des valeurs caractéristiques — Partie 3 Exigences pour les bois[.]
INTERNATIONAL STANDARD ISO 12122-3 First edition 2016-07-01 Timber structures — Determination of characteristic values — Part 3: Glued laminated timber Structures en bois — Détermination des valeurs caractéristiques — Partie 3: Exigences pour les bois lamellé-collé Reference number ISO 12122-3:2016(E) © ISO 2016 ISO 12122-3:2016(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2016, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2016 – All rights reserved ISO 12122-3:2016(E) Contents Page Foreword iv Introduction v Scope Normative references Terms and definitions Symbols and abbreviated terms Reference population Sampling 6.1 6.2 Sampling method Sample size 8.1 8.2 8.3 Test method Test data compatible with product description Failure modes 9.1 Structural properties f ff f 9.3.1 Characteristic bearing strength f percentile test value Sample conditioning Test data Evaluation of characteristic values for structural properties 9.2 9.3 C haracteris tic mo dulus o C haracteris tic values o 9.3 elas ticity o r s ti nes s s trength o r cap acity O ther characteris tic values o r s trength o r cap acity b as ed o n the th 10 Report Annex A (informative) Commentary Annex B (informative) Analytical models for determining characteristic properties of glued laminated timber Bibliography © ISO 2016 – All rights reserved iii ISO 12122-3:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso.org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) Any trade name used in this document is in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html The committee responsible for this document is ISO/TC 165, Timber structures ISO 12122 consists of the following parts, under the general title Timber structures — Determination of characteristic values: — Part 1: Basic requirements — Part 2: Sawn timber — Part 3: Glued laminated timber — Part 4: Engineered wood products1) — Part 6: Large components and assemblies1) The following parts are under preparation: — Part 5: Mechanical connections 1) To be published iv © ISO 2016 – All rights reserved ISO 2 -3 : 01 6(E) Introduction This part of ISO 12122 sets out a framework for establishing characteristic values from test results on a s ample d rawn from a cle arly defi ne d re ference p opu lation o f glue d l am i nate d ti mb er T he charac teri s tic va lue i s an e s ti mate o f the prop er ty o f the re ference p opu lation with a s i s tent level o f fidence prescribed in this part of ISO 12122 T h i s p a r t o f I S O 2 i s to b e u s e d i n conj u nc tion with I S O 2 -1 This part of ISO 12122 permits the evaluation of characteristic values on testing on commercial sized specimens of glued laminated timber Where the characteristic values are derived using calculations f Annex B references other methods for estimating characteristic values b a s e d on la m i nate s tr uc tu l prop er tie s , th i s p a r t o I S O 2 e s no t apply, but I n s ome c as e s , charac teri s tic va lue s de term i ne d i n accorda nce with th i s p ar t o f I S O 2 may b e mo d i fie d to b e come a de s ign va lue This part of ISO 12122 has the following annexes: — Annex A f — Annex B laminated timber pre s ents a com mentar y on th i s p a r t o f I S O 2 ; pre s ents i n ormation on a na lytic a l mo del s © ISO 2016 – All rights reserved for de term i n i ng charac teri s tic va lue s o f glue d v INTERNATIONAL STANDARD ISO 12122-3:2016(E) Timber structures — Determination of characteristic values — Part 3: Glued laminated timber Scope T h i s p ar t o f I S O 121 22 give s me tho d s for the de term i nation o f charac teri s tic va lue s population of glued laminated timber products, calculated from test values It presents methods for the determination of a) characteristic value of mean-based properties, and b) for a defi ne d charac teri s tic va lue o f th p ercenti le -b as e d prop er tie s NOTE Annex B f f characteristic values of glued laminated timber products from properties of the laminates give s i n o rm ation on the me tho d s th at h ave b e en s ucce s s u l l y used to e s ti m ate the Normative references T he fol lowi ng i nd i s p en s able c u ments , i n whole or i n p ar t, are normatively re ference d i n th i s c u ment a nd are for its appl ic ation For date d re ference s , on ly the e d ition cite d appl ie s For u ndate d re ference s , the late s t e d ition o f the re ference d c u ment (i nclud i ng any amend ments) appl ie s Timber structures — Glued laminated timber — Test methods for determination of physical and mechanical properties I S O 75 , ISO 12122-1, Timber structures — Determination of characteristic values — Part 1: Basic requirements Terms and definitions For the pu rp o s e s o f th i s c u ment, the term s and defi n ition s given i n I S O 2 -1 and I S O 78 apply ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia.org/ — ISO Online browsing platform: available at http://www.iso.org/obp Symbols and abbreviated terms Symb ol s defi ne d i n the relevant I S O pro duc t or te s t s ta nda rd sh a l l b e u s e d O ther s ymb ol s are defi ne d in ISO 12122-1 Reference population I n add ition to the re qu i rements for defi n ition o f the re ference p opu lation i n I S O 2 -1 , the fol lowi ng attribute s o f glue d lam i nate d ti mb er may b e i nclude d: a) s ou rce s o f raw materia l; © ISO 2016 – All rights reserved ISO 12122-3:2016(E) b) s e as on i ng me tho d (i f s e a s one d) ; c) grad i ng or pro duc tion me tho d d) layup o f the glue d la m i nate d pro duc t; e) s p e ci fic ation o f ad he s ive s , me tho d o f appl ic ation a nd me tho d o f c uri ng ad he s ive s; f) qua l ity control me a s ure s; g) va ri ation s i n the lam i nate s (i f a ny) for la m i nate s i nclud i ng pre s ence and fre quenc y o f fi nger j oi nts; Sampling 6.1 Sampling method T he s ampl i ng me tho d s l l comply with the p er forma nce obj e c tive o f s ampl i ng defi ne d i n I S O 2 -1 Representation of each of the variants in the sample shall approximate the representation of the same variants in the reference population The sampling method shall be documented in the report as detailed in Clause 10 and this documentation f f f compliance with and in ISO 12122-1 or otherwise important to the description of the reference population sha l l i nd ic ate a re s p on s e to e ach o the identi fie d attribute s o the re erence p opu l ation l i s te d in C lau s e 6.2 Sample size T he s ample s i ze s l l comply co e fficient o f variation ( with re qu i rements of I SO 2 -1 and sh a l l ta ke i nto accou nt the V) expected for the glued laminated timber in the reference population NOTE See notes under the relevant clause in ISO 12122-1 NOTE ISO 12122-1 gives some guidance on selecting sample size Sample conditioning T he s ample s torage and te s ti ng envi ron ment sh a l l refle c t cond ition i ng i n accordance with the defi n ition of the reference population as indicated in ISO 12122-1 Due to the large size of glued laminated timber, accordance with 8.2 it i s accep table to te s t the s a mple at a s -te s te d cond ition s provide d that the re s u lts a re adj u s te d i n Test data 8.1 Test method The test data shall be obtained from a) I S O 75 , or b) a standard test method appropriate for the glued laminated timber reference population provided e qu iva lenc y NOTE fac tors with I S O 75 c an b e e s tabl i she d See notes under the relevant clause in ISO 12122-1 Te s t me tho d s i nvolve many vari able s that wi l l a ffe c t re s u lts i nclud i ng lo ad i ng figu ration a nd rate s , specimen positioning and measurement methods The level of precision of these variables should be f 8.2 appropriate to the obj e c tive s o the te s ti ng and the adj u s tments re qu i re d i n © ISO 2016 – All rights reserved ISO 12122-3:2016(E) 8.2 Test data compatible with product description Where the characteristic value is applicable to a standard size or moisture content, adjustments to the raw test data may be required Any adjustment shall be in accordance with ISO 12122-1 and shall be detailed in the report NOTE These adjustments include those required to pool data from di fferent test programs as outlined in ISO 12122-1 8.3 Failure modes The failure modes obtained in the tests shall be recorded The data shall only be included in the analysis i f it comes from a test in which the failure mode appropriate to the property was obtained NOTE The same test method may produce di fferent failure modes on di fferent products The characteristic value may be underestimated by tests that produce failure modes that are di fferent to ones that the test method was intended to produce Evaluation of characteristic values for structural properties 9.1 Structural properties For glued laminated timber, determination of the characteristic values for structural properties shall be in accordance with ISO 12122-1 using data of material properties from glued laminated timber tests (see Annex A for more information) NOTE Annex A gives guidance on the type of property that is appropriate for glued laminated timber 9.2 Characteristic modulus of elasticity or stiffness The characteristic modulus o f elasticity or sti ffness used for serviceability shall be the mean value taken as the average of the test values evaluated in accordance with ISO 12122-1, and in the case of its use in the ultimate limit state it shall be either the average or the 5th percentile value NOTE In some cases, where a reduction o f modulus o f elasticity or sti ffness is not already factored into the behaviour equation used for design, a 5th percentile value o f modulus o f elasticity can be required to design for beam or column stability 9.3 Characteristic values of strength or capacity 9.3.1 Characteristic bearing strength The characteristic values for bearing strength, both parallel and perpendicular to grain, shall be the mean property obtained from results o f tests 9.3.2 Other characteristic values for strength or capacity based on the 5th percentile test value The 75 % lower single-sided confidence limit o f the test 5th percentile value shall be evaluated Suitable methods for evaluating the 5th percentile value o f the test data and estimating the 75 % lower singlesided confidence limit are presented in ISO 12122-1 10 Report The report shall comply with the requirements o f ISO 12122-1 © ISO 2016 – All rights reserved ISO 2 -3 : 01 6(E) Annex A (informative) Commentary A.1 Commentary on scope This part of ISO 12122 presents methods for determining characteristic values for glued laminated structural timber It is to be used in conjunction with ISO 12122-1 The part o f ISO 12122 presents a uni form methodology for the evaluation o f characteristic values that are consistent with the characteristic values found for other structural timber products The part o f ISO 12122 does not establish methods for the determination o f design values These may be determined based on characteristic values from test data, but for glued laminated timber will also incorporate appropriate sa fety factors to account for any or all o f the following factors — Expected changes in product or product properties over a long period These changes could be due to variations in timber resource quality, production methods or adhesives — The complexity o f the re ference population For example, where the re ference population has a large number o f producers who draw their resource over a large area, then the sampling may not e ffectively reflect all possible combinations o f resource quality and production methods In this way, the sample may not be truly representative and a sa fety factor may be applied to allow for that — Variations over time o f the layup used for the glued laminated timber These variations may include presence or frequency o f finger joints — Anticipated variations in quality control across the re ference population in the future Characteristic values presented in this part o f ISO 12122 relate only to the determination o f characteristic values from the results of tests on full-scale glued laminated timber products The properties for glued laminated timber are estimated from calculation using models that relate the laminate properties to the properties of the composite beams The scope of this part of ISO 12122 does not cover these methods, but Annex B contains in formation linking to some commonly accepted models for these calculations This part o f ISO 12122 can be used to veri fy such models using tests on full-scale glued laminated timber products whole suite o f ISO 12122 standards has this common basis However, in many cases, the characteristic A.2 Commentary on normative references No commentary A.3 Commentary on terms and definitions No commentary (See ISO 12122-1) A.4 Commentary on symbols No commentary (See ISO 12122-1) © ISO 2016 – All rights reserved ISO 2 -3 : 01 6(E) A.5 Commentary on reference population Characteristic values can be taken to represent the properties of the material from which the sample wa s ta ken T he re ference p opu lation i s the defi n ition o f the p arent p opu l ation to wh ich the cha rac teri s tic prop er tie s a re s aid to apply I S O 2 -1 pre s ents s ome genera l re qu i rements re ference p opu l ation, but s ome o ther laminated timber — fe atu re s for defi n ition o f the a re known to i n fluence the s truc tura l prop er tie s o f glue d T he prop er tie s o f the wo o d th at i s the raw materi a l for the glue d la m i nate d ti mb er pro duc t may a ffe c t the prop er tie s o f the fi na l pro duc t T h i s me an s that the defi n ition o f the re ference p opu lation should include all possible sources of wood for the product This will also require sampling across f f f reference population the — u l l nge o raw materia l s ou rce s to en s u re that the te s t s a mple i s tru ly repre s entative o the Temp erature o f s e as on i ng may a l s o have an i n fluence on the s truc tu l prop er tie s o f s e a s one d wo o d materia l s Range o f s e a s on i ng temp eratu re s and the me tho d o f s e a s on i ng , wh ich may relate to the speed of moisture removal, should be declared — Grad i ng o f raw materia l and pro duc tion me tho d s employe d may a l s o have a s igni ficant i n fluence on the prop er ties o f the comple te d glue d lam i nate d ti mb er pro duc ts I n s ome c as e s , relatively s ma l l change s i n gradi ng (e g variation o f lam i nate kno t l i m its) may s ign i fic antly a ffe c t s ome prop er ties L i kewi s e, s ome manu fac tu ri ng detai l s may b e critic al to s ome pro duc t prop er ties i nclude pre s ence o f fi nger-j oi nts i n outer lami nation s , sharpne s s o f c utters or holdi ng pre s s ure s and ti me s for for T he s e may pro fi l i ng fi nger j oi nts glue d j oi nts Where a re ference p opu lation may b e d rawn from plants that u s e a range o f manu fac tu ri ng pro ce s s e s , they shou ld a l l b e repre s ente d i n the te s t s ample — The behaviour of the adhesive under applied load is often crucial to product structural performance H ence, a ny fac tor that may i n fluence the s treng th o f the ad he s ive sh a l l b e l i n ke d to the re ference p opu lation Where a nge o f ad he s ive s p e c i fication s , hand l i ng and appl ic ation me tho d s or c u ri ng me tho d s may b e pre s ent i n the re ference p opu lation, the s e va ri ation s shou ld b e de cla re d and c are s hou ld b e ta ken to en s u re that they a re a l l i nclude d i n the repre s entative s ample — Qua l ity control me a s u re s are o ften u s e d to mai nta i n va riou s a s p e c ts o f pro duc tion that c an a ffe c t s tr uc tu l prop er tie s Sp e c i fic ation o f the qua l ity control pro ce s s e s i s an i mp or ta nt s ideration i n defi n i ng the re ference p opu l ation I de a l ly, a l l pro ducers i nclude d i n the re ference p opu lation s hou ld have the s ame qua l ity control me a s u re s , but where there are vari ation s , the s e shou ld a l l b e i nclude d i n the s p e c i fic ation o f the re ference p opu lation — Where the pro duc t s p e c i fic ation u s e s l am i nate s o f d i fferent grade s u s e d i n d i fferent p ar ts o f the glued laminated beam, this should be declared as a characteristic of the reference population All pro ducers i n the re ference p opu l ation shou ld b e u s i ng the s ame l ayup s p e c i fic ation as it u s ua l ly s a s igni fic a nt e ffe c t on the s truc tu l prop er tie s o f the pro duc t Where the characteristic values are to be material properties (e.g bending strength, fm), it is possible f f f ff can be evaluated using the different geometric parameters for each size If this is the case, the size range in the reference population should be declared ISO 12122-1 refers to the period over which the product was manufactured In some climates, the time that the re erence p opu lation c a n i nclude a range o s i z e s as the c ap ac ity o the d i erent s i z e d pro duc ts o f ye ar c an a ffe c t the prop er tie s o f the raw materi a l s or manu fac tu ri ng pro ce s s e s i n u s e The lists in ISO 12122-1 and in this part of ISO 12122 are examples, but the intent of the clause is that in the description anyth i ng i n the ma nu fac tu re o f the pro duc t th at may a ffe c t the s truc tura l prop er tie s sh al l b e i nclude d © ISO 2016 – All rights reserved ISO 2 -3 : 01 6(E) A.6 Commentary on sampling Where the reference population of the glued laminated timber products includes a number of different manufacturers or processes, care should be taken to ensure that all variations in raw material and production methods are included in the representative sample Although glued laminated timber products may have lower coe fficients o f variation (V) within a product specification compared with other timber products, variations in raw materials or production methods may contribute to higher V for a whole reference population compared with product from a single manufacturer The list o f features to be described in the re ference population (from ISO 12122-1:2014; Clause and A.5 ) can be used to derive a sampling program that will include all of the variations in the reference population Tests on glued laminated timber products with lower coe fficients o f variation than sawn timber can use smaller sample sizes Guidance on sample size can be found in ISO 12122-1 A.7 Commentary on sample conditioning Most glued laminated timber products are seasoned Samples shall be stored so that the moisture content remains within the requirements for the seasoned product Otherwise the requirements o f ISO 12122-1 apply A.8 A.8.1 Commentary on testing Commentary on test method ISO 8375 presents test methods for most structural properties for glued laminated timber Other properties can be tested in accordance with other recognized timber test international and national standards A.8.2 Commentary on test data compatible with product description Adjustment o f the test data to a re ference size, moisture content or temperature may be required Where this is per formed, it shall comply with the requirements o f ISO 12122-1 For glued laminated timber, the characteristic properties often relate to a reference size, and hence where pooling of data on different sizes takes place, the data shall be corrected to the standard size In order to this, the guidelines on pooling in ISO 12122-1 should be care fully followed A.8.3 Commentary on failure modes Where tests are aimed at a particular structural property, but a di fferent failure mode has occurred, then the intended property may be underestimated by the test data An example is the test for flexural strength, fm , may be per formed, but shear failures or longitudinal glue line failures may be produced In this case, the calculated flexural strength from the test is a lower bound on the true bending strength of the product Where the failure mode obtained in the test involved glue failures, this may indicate that the glue lines are not stronger than the timber, and as a result, calculation methods for the determination of characteristic values may not be valid and the product may not comply with the relevant product standard © ISO 2016 – All rights reserved ISO 12122-3:2016(E) A.9 Commentary on evaluation of characteristic values for structural properties A.9.1 Commentary on structural properties Struc tu l prop er tie s o f glue d lam i nate d ti mb er are genera l ly pre s ente d a s mo du lu s o f elas ticity a nd for s treng th s that s l l b e mu ltipl ie d b y a relevant ge ome tric prop er ty — de s ign Streng th s are pre s ente d i n the s a me u n its as s tre s s a nd mu ltipl ie d b y an are a to give a force or a s e c tion mo du lu s to give a moment a s the s e c tion c ap acity — Mo du lus o f elas ticity (in the s ame units as s tres s) is us ed in the calculation o f de formation under lo ad T a b l e A — C l a s s i f i c a t i o n o f c h a r a c t e r i s t i c v a l u e s f o r g Characteristic value Characteristic properties Bending strength, f Tension strength, f , parallel to grain Compression strength, f , parallel to grain Shear strength, f Compression strength, f , perpendicular to grain Tension strength, f 90 , perpendicular to grain m t, c, s c,90 t, M o du lu s o f el a s tic ity, E I nd ic ate s th at fo r u e d l a m i n a t e Basis d t i m b e r Typical units (5 th p ercenti le) a MPa MPa MPa MPa MPa MPa MPa or GPa (5 th p ercenti le) a MPa th p ercenti le th p ercenti le th p ercenti le th p ercenti le Mean (5 th p ercenti le) a th p ercenti le Mean Mean Shear modulus, G a l s o me p ro duc ts , a th p ercenti le va lue m ay b e re qu i re d i n add i tio n to the no r m a l me a n- b a s e d va lue A.9.2 Commentary on characteristic modulus of elasticity No com menta r y (S e e I S O 2 -1) A.9.3 Commentary on characteristic values of strength No com menta r y (S e e I S O 2 -1) A.10 Commentary on report No com menta r y (S e e I S O 2 -1) © ISO 2016 – All rights reserved ISO 2 -3 : 01 6(E) Annex B (informative) Analytical models for determining characteristic properties of glued laminated timber B.1 General In some cases, the characteristic values of glued laminated timber can be calculated from the f sharing of strength between the laminations that gives the completed section a higher characteristic charac teri s tic prop er tie s o the lam i nation s T he s e mo del s are s treng th th an that o f its lam i nation s T he s e mo del s are genera l ly — s tati s tic a l ly b as e d fou nde d on the a nd fol lowi ng rely on the pri nc iple s T he glue j oi nt may b e re qu i re d to b e a s s as the ti mb er i n the lam i nation th rough the i n-pl ant pro ce s s control O ther wi s e, the mo del shou ld s ider the s treng th o f the glue j oi nt i n add ition to the strength of the timber component — T he prop er tie s o f glue d lam i nate d ti mb er a re en h ance d b y the placement o f la m i nati ng lu mb er i n different location or orientation based on the principle of engineering mechanics — There are a large enough number of laminations to allow reinforcement of potential weaknesses f neutral axis i n i nd ividua l la m i nation s b y adj acent lam i nation s on b o th the ten s ion and compre s s ion s ide o B.2 the Models S evera l ana lytica l mo del s th at h ave b e en s ucce s s fu l ly u s e d i n mo del l i ng s ele c te d me ch an ic a l prop er tie s of glued laminated timber are available from different countries or regions While some models are stochastic and the others are deterministic in nature, most models are capable of predicting the charac teri s tic prop er ty va lue s o f glue d lam i nate d ti mb er i n compl i ance with th i s p a r t o f I S O 2 © ISO 2016 – All rights reserved ISO 2 -3 : 01 6(E) Bibliography I S O 78 , Timber structures — Glued laminated timber — Component performance requirements © ISO 2016 – All rights reserved ISO 2 -3 : 01 6(E) I CS 91 080.2 Price based on pages © ISO 2016 – All rights reserved