© ISO 2017 Timber structures — Determination of characteristic values — Part 4 Engineered wood products Structures en bois — Détermination des valeurs caractéristiques — Partie 4 Produits bois reconst[.]
INTERNATIONAL STANDARD ISO 12122-4 First edition 2017-01 Timber structures — Determination of characteristic values — Part 4: Engineered wood products Structures en bois — Détermination des valeurs caractéristiques — Partie 4: Produits bois reconstitués Reference number ISO 12122-4:2017(E) © ISO 2017 ISO 12122-4:2017(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2017, 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 2017 – All rights reserved ISO 12122-4:2017(E) Contents Page Foreword iv Introduction v Scope Normative references Terms and definitions Symbols 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 9.2 Structural properties Characteristic values of material properties f 9.2.2 Characteristic bearing strength 9.2.3 Other characteristic values for strength based on the 5th percentile test value Characteristic values of component properties 9.3.1 Characteristic stiffness 9.3.2 Characteristic bearing strength 9.3.3 Other characteristic capacities for strength based on the 5th percentile test value Sample conditioning Test data Evaluation of characteristic values for structural properties 9.2 9.3 C haracteris tic mo dulus o elas ticity and s hear mo dulus 10 Report Annex A (informative) Commentary Annex B (informative) Analytical models for determining characteristic properties of engineered wood products 10 Bibliography 11 © ISO 2017 – All rights reserved iii ISO 12122-4:2017(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 A list of all the parts in the ISO 12122 series can be found on the ISO website iv © ISO 2017 – All rights reserved ISO 2 -4: 01 7(E) Introduction This document sets out a framework for establishing characteristic values from test results on a sample d rawn from a cle arly defi ne d re ference p opu lation o f engi ne ere d wo o d pro duc ts 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 the standard T h i s c ument i s i ntende d to b e u s e d i n conj u nc tion with I S O 2 -1 This document permits the evaluation of characteristic values on testing on commercial engineered wood products I n s ome c as es , cha rac teri s tic va lue s de term i ne d i n accord ance with th i s c u ment may b e mo d i fie d to become a design value The document has the following annexes: — Annex A — Annex B presents information on methods for calculating characteristic values from component properties pre s ents a com mentar y on th i s c ument; © ISO 2017 – All rights reserved v INTERNATIONAL STANDARD ISO 12122-4:2017(E) Timber structures — Determination of characteristic values — Part 4: Engineered wood products Scope T h i s c u ment give s me tho d s o f de term i nation o f charac teri s tic va lue s engineered wood products calculated from test values This document presents methods for the determination of a) charac teri s tic va lue o f materia l prop er tie s , where the for a defi ne d p opu lation o f de term i ne d prop er ty i s mu ltipl ie d b y a ge ome tric p ara me ter to give a comp onent c ap ac ity or comp onent s ti ffne s s , or b) charac teri s tic va lue of comp onent prop er tie s d i re c tly, where the de term i ne d prop er ty is a comp onent c ap acity or comp onent s ti ffne s s This document presents methods for determination of a) characteristic value of mean-based properties, and b) characteristic value of 5th percentile-based properties Normative references T he fol lowi ng c u ments are re ferre d to i n the tex t i n s uch a way th at s ome or a l l o f thei r content s titute s re qu i rements o f th i s c u ment 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 ument (i nclud i ng a ny amend ments) appl ie s ISO 12122-1:2014, Timber structures — Determination of characteristic values — Part : Basic requirements Terms and definitions ISO 12122-1 f 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 For the purpo ses o f this cument, the terms and definitions given in and the ollowing apply 3.1 engineered wood product item manu fac tu re d from wo o d , na mely ply wo o d, oriente d s tra nd b o a rd, I b e a m s , lam i nate d vene er lumber or structural insulated panel walls N o te to entr y: T he s e p ro duc ts th at a re de fi ne d i n I S O , I S O 16 4, I S O 2 -1 , I S O 2 a nd I S O 2 45 © ISO 2017 – All rights reserved ISO 2 -4: 01 7(E) Symbols Symb ol s defi ne d i n the relevant I S O pro duc t or te s t s tandard sha l l b e us 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 engi ne ere d wo o d pro duc ts may b e de s crib e d: a) s ou rce s o f raw materi a l; b) s e as on i ng me tho d (i f s e a s one d) ; c) grading or production method for components of the engineered wood product where it is made of previou s ly grade d comp onents (i nclud i ng la mel lae) ; d) 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 u ri ng ad he s ive s; e) qua l ity control me a s ure s; f) s e condar y pro ce s s i ng , s uch as pre s er vative tre atment, fi re re tardant tre atment, pro fi l i ng , e tc ; g) va ri ation s i n the figuration o f the pro duc t (i f a ny) 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 See Clause 10 and ISO 12122-1 for reporting requirements on the sampling method The report should f f f with Clause or otherwise important to the description of the reference population i nd ic ate a re s p on s e to e ach o 6.2 T he the identi fie d attribute s o the re erence p opu lation l i s te d i n compl i ance Sample size 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 V) expected for the sawn timber in the reference population i nto accou nt the NOTE See notes under the relevant clause in ISO 12122-1 E ngi ne ere d wo o d pro duc ts ’ prop er tie s genera l ly have lower p opu lation co e fficients o f va ri ation ( structural properties and should therefore have a smaller sample size V) in 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 © ISO 2017 – All rights reserved ISO 12122-4:2017(E) Test data 8.1 Test method The test data shall be obtained from a) tests in accordance with the ISO test standard relevant to the product, or b) a standard test method appropriate for the re ference population, provided equivalency factors with the relevant ISO test standard can be established NOTE See notes under the relevant clause in ISO 12122-1 Test methods involve many variables that will a ffect results including loading configuration and rates, specimen positioning and measurement methods The level of precision of these variables should be appropriate to the objectives o f the testing and the adjustments required in 8.2 8.2 Test data compatible with product description Where the characteristic value is applicable to a standard size or moisture content, adjustments to the 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 the ones that the test method was intended to produce Evaluation of characteristic values for structural properties 9.1 Structural properties For engineered wood products, either material properties or component properties shall be evaluated NOTE Annex A gives guidance on the type o f property that is appropriate for some common engineered wood products NOTE Where component properties are reported, they are in general specific to a given size o f product Different sized products will have different component properties Determination of the characteristic values for structural properties shall be in accordance with ISO 12122-1 unless specifically specified in the re ference product standard 9.2 Characteristic values of material properties 9.2.1 Characteristic modulus of elasticity and shear modulus The characteristic modulus o f elasticity and shear modulus shall be the mean value, taken as the average of the test values evaluated in accordance with ISO 12122-1 © ISO 2017 – All rights reserved ISO 2 -4: 01 7(E) 9.2 Characteristic bearing strength The characteristic values for bearing strength, both parallel and perpendicular to grain, shall be the me a n prop er ty ob tai ne d 9.2 from re s u lts o f te s ts Other characteristic values for strength based on the th percentile test value T he 75 % lower s i ngle - s ide d fidence l i m it o f the te s t th p ercenti le va lue s l l b e eva luate d Su itab le methods for evaluating the 5th percentile value of the test data and estimating the 75 % lower single- s ide d fidence l i m it are pre s ente d i n I S O 2 -1 9.3 9.3 Characteristic values of component properties Characteristic stiffness The characteristic stiffness shall be the mean value, taken as the average of the test values evaluated in accordance with ISO 12122-1 9.3 Characteristic bearing strength The characteristic values for bearing strength evaluated in accordance with 9.2.2, both parallel and p erp end ic u lar to gra i n, sh a l l b e the me a n prop er ty ob ta i ne d NO TE from re s u lts o f te s ts E ven though o ther p rop er tie s a re co mp onent pro p er tie s , b e a r i n g s treng th s a re genera l l y rep or te d a s material properties Further guidance is given in Annex A 9.3 Other characteristic capacities for strength based on the th percentile test value T he 75 % lower s i ngle - s ide d fidence l i m it o f the te s t th p ercenti le va lue s l l b e eva luate d Su itab le methods for evaluating the 5th percentile value of the test data and estimating the 75 % lower singles ide d fidence l i m it are pre s ente d i n I S O 2 -1 Report T he rep or t s l l comp ly with the re qui rements o f I S O 2 -1 © ISO 2017 – All rights reserved ISO 2 -4: 01 7(E) Annex A (informative) Commentary A.1 Commentary on scope This document presents methods for determining characteristic values for engineered wood products It is to be used in conjunction with ISO 12122-1 This document 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 This document does not establish methods for the determination o f design values, which may be determined based on characteristic values from test data by incorporating 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 changes in other raw materials — The complexity o f the re ference population For example, where the re ference population has a large number of producers who draw their resources over a large area or use different production parameters, 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 in time o f the assembly used for the engineered wood product These variations may include end-joint treatment o f elements, element specification, curing and holding times — Anticipated variations in quality control across the re ference population in the future Characteristic values presented in this document relate only to the determination o f characteristic values from the results of tests on full-scale engineered wood products The ISO 12122- series has this common basis However, in many cases, the characteristic properties for engineered wood products are found from calculation using models that relate the properties of the individual elements to the properties of the composite products The scope of this document does not cover these methods, but Annex B contains in formation linking to some commonly accepted models for these calculations This document can be used to veri fy such models using tests on full-scale engineered wood products 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 2017 – All rights reserved ISO 2 -4: 01 7(E) A.5 Commentary on reference population Characteristic values can be taken to represent the properties of the material from which the sample was ta ken T he re ference p opu lation i s the defi n ition o f the p a rent p opu lation to wh ich the charac teri s tic prop er tie s are s aid to apply I S O 2 -1 pre s ents s ome genera l re qu i rements re ference p opu lation, but s ome o ther engineered wood products — fe atu re s for defi n ition o f the a re known to i n fluence the s truc tu l prop er tie s o f T he prop er tie s o f the wo o d that i s the raw materia l for the engi ne ere d wo o d 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 s hou ld include all possible sources of wood for the product This also will require sampling across the f f reference population fu l l — range o raw materia l s ou rce s to en s ure th at the te s t s ample i s tru ly a repre s entative o the Temp eratu re o f s e as on i ng may a l s o have an i n fluence on the s truc tura l prop er tie s o f s e as one d wo o d materi a l s Range o f s e as on i ng temp eratu re s and me tho d o f s e a s on i ng , wh ich may rel ate 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 ign i fic ant i n fluence on the prop er tie s o f the comple te d engi ne ere d wo o d pro duc ts I n s ome c a s e s , rel ati vely s ma l l ch ange s i n grad i ng (e g va riation o f wo o d materia l den s ity l i m its) may s ign i fic antly a ffe c t s ome prop er tie s L i kewi s e s ome ma nu fac turi ng de tai l s may b e c ritic a l to s ome pro duc t prop er tie s T he s e may i nclude sh arpne s s o f c utters for pro fi l i ng s ome pro duc ts or hold i ng pre s s u re s and ti mes s ome glue d pro duc ts Where a re ference p opu l ation may b e d rawn from for pla nts that u s e a nge 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 — M o s t engi ne ere d wo o d pro duc ts employ ad he s ive s and the b eh aviou r o f the ad he s ive u nder app l ie d lo ad i s o ften cruc ia l to its p er formance H ence any fac tor th at may i n fluence the s treng th o f the ad he s ive s hou ld 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 fic ation s , nd 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 vari ation s shou ld b e de cl are d and c are shou ld b e ta ken to en s ure that they are a l l i nclude d i n the representative sample — Qua l ity control me a s u re s are o ften u s e d to mai ntai n variou s a s p e c ts o f pro duc tion that c an a ffe c t s truc 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 tant s ideration i n defi ni ng the re ference p opu lation I de a l ly, a l l pro ducers i nclude d i n the re ference p opu lation s hou ld h ave the s a me qua l ity control me as u re s , but where there are vari ation s , the s e s hou 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 l ation — S e condar y pro ce s s i ng , s uch a s pre s er vative tre atment, fi re re tardant tre atment, pro fi l i ng , e tc , may affect the material properties and should be kept consistent for the same referenced population under evaluation — Where s ome pro duc ts a re re s tric te d i n thei r appl ic ation, they shou ld genera l ly b e regarde d as a s ep arate pro duc t to s i m i la r u nre s tric te d appl ic ation pro duc ts Re s tric tion s i n appl ic ation may le ad to differences in manufacturing processes or testing for some properties Where the characteristic values are to be product properties (e.g bending strength, fm), it is possible f f f ff can be evaluated using the different geometric parameters for each size However, for characteristic f f f Different sized cross-sections will have different capacities and stiffness 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 an i nclude a range o va lue s o comp onent prop er tie s , the re erence s i z e s a s the c ap acity o p opu l ation c an the d i on ly re er to a erent s i z e d pro duc ts s i ngle size pro duc t o f ye a r c a n a ffe c t the prop er tie s o f the raw materia l s or manu fac tu ri ng pro ce s s e s i n u s e T he l i s ts i n I S O 2 -1 a nd th i s c ument are example s , but the i ntent o f the clau s e i s that a nyth 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 tu l prop er tie s shou ld b e i nclude d i n the description © ISO 2017 – All rights reserved ISO 2 -4: 01 7(E) A.6 Commentary on sampling Where the reference population of the engineered wood 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 While engineered wood products often have lower coe fficients o f variation (V) within a product specification compared with other timber products, variations in raw material or production methods may contribute to higher V for a whole reference population compared with product from a single manufacturer The list of features to be described in the reference 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 engineered wood 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 engineered wood products are seasoned Samples should 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 Each engineered wood product has separate testing requirements designed to fully explore the failure modes possible with the product The test method should be compatible with the product specification ISO test methods for each product are the reference test methods, but where other test methods have demonstrated that they capture all possible failure modes and are compatible with the relevant ISO test method, they can also be used The key point in this clause is that the test method is the appropriate test method for the particular type o f engineered wood product described in the re ference population A.8.2 Commentary on test data compatible with product description Where adjustment o f the test data to a re ference size, moisture content or temperature is required, it should comply with the requirements o f ISO 12122-1 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 tests for shear capacity o f I-beams may be per formed, but i f bearing failures limit the test, then the calculated shear capacity from the test is a lower bound on the true shear capacity o f 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 as the product does not comply with the relevant ISO product standard © ISO 2017 – All rights reserved ISO 12122-4:2017(E) A.9 Commentary on evaluation of characteristic values for structural properties A.9.1 Commentary on structural properties The method of presentation of the structural properties for engineered wood products depends on the geometric form of the product: — I n genera l, pro duc ts with a re c tangu la r c ro s s- s e c tion a nd are manu fac tu re d enti rely o f elements with s i m i la r prop er tie s (e g plywo o d a nd LVL) wi l l give materi a l prop er tie s (s e e A.9.2) and capacities Sti ffne s s i s ca lc u late d when the materia l prop er tie s are mu ltipl ie d b y ge ome tric p a rame ters — I n genera l, pro duc ts with a non-re c ta ngu la r cro s s - s e c tion or made with elements th at h ave ver y different properties (e.g I-beams and structural insulated panels) will give component properties (see A.9.3) The characteristic values will be the capacities and stiffness of the whole component 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 Characteristic value Characteristic properties Bending strength, f Tension strength, f ,0 , parallel to grain Compression strength, f , parallel to grain Shear strength, f Compression strength, f 90 , perpendicular to grain Tension strength, f 90 , perpendicular to grain m t c, s c, t, M o du lu s o f el a s tic ity, E Shear modulus, G a I nd ic ate s th at fo r s f o r e n g i n e e r e d w o o d p r o d u c t s Basis Typical units 5th percentile 5th percentile 5th percentile 5th percentile Mean (5th percentile) a 5th percentile Mean (5th percentile) a Mean (5th percentile) a MPa MPa MPa MPa MPa MPa MPa or GPa MPa s o me p ro duc ts , a th p e rce nti 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 values of material properties M ateri a l prop er tie s i nclude mo du lu s o f elas ticity and s treng th va lue s a s i nd ic ate d i n these properties will have the units of GPa or MPa Table A.1 All of A.9.2.1 Commentary on characteristic modulus of elasticity and shear modulus No com mentar y (S e e I S O 2 -1 ) A.9.2.2 Commentary on characteristic bearing strength No com mentar y (S e e I S O 2 -1 ) A.9.2.3 Commentary on other characteristic values for strength based on the 5th percentile test value No com mentar y (S e e I S O 2 -1 ) A.9.3 Commentary on characteristic values of component properties C omp onent prop er tie s i nclude flexu l s ti ffne s s a nd c ap acity va lue s with typic a l u n its as i nd ic ate d i n Table A.2 © ISO 2017 – All rights reserved ISO 12122-4:2017(E) Table A.2 — Typical units for characteristic capacity values for structural component properties Characteristic value Characteristic capacity properties B end i n g c ap ac ity, M Ten s io n c ap ac ity, Nt ,0 , parallel to grain Nc,0 , parallel to grain C o mp re s s io n c ap ac ity, Shear strength, V Compression strength, N ,90 , perpendicular to grain Tension strength, T ,90 , perpendicular to grain Flexural stiffness, EI c t Axial stiffness, EA Shear stiffness, GA a I nd ic ate s th at based value NO TE fo r s o me Basis Typical units 5th percentile 5th percentile 5th percentile 5th percentile Mean (5th percentile) a 5th percentile Mean (5th percentile) a Mean (5th percentile) a Mean (5th percentile) a kN·m kN kN kN kN kN kN·m kN kN 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 e a r i ng c ap ac ity c a n on l y b e c a lc u l ate d from a b e a r i n g a re a a nd b e a r i ng s tren g th T he s treng th i s genera l l y l i m ite d b y the wo o d comp onents i ntende d to b e i n co ntac t with the b e a r i ng (S e e b e a r i ng A.9.3.2.) A.9.3.1 Commentary on characteristic stiffness As indicated in Table A.2 , a nu mb er o f d i fferent s ti ffne s s may b e re qu i re d F lexu l s ti ffne s s wi l l b e d i fferent to the a xi a l s ti ffne s s rep or te d T h i s wi l l re qu i re d i fferent te s ti ng a nd ana lys i s A.9.3.2 Commentary on characteristic bearing strength Streng th s p er p end ic u la r to grai n shou ld s ti l l b e eva luate d a s s treng th s rather th an c ap acity B e ari ng c ap acity i s a func tion o f the s i z e o f the b e ari ng a nd its are a T he b e a ri ng c ap acity c a n b e i nd ividua l de s ign s ituation s by mu ltiplyi ng the b e a ri ng s treng th, fc, 90 fou nd in , b y the b e a ri ng a re a A.9.3.3 Commentary on other characteristic capacities for strength based on the 5th percentile test value 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 2017 – All rights reserved ISO 2 -4: 01 7(E) Annex B (informative) Analytical models for determining characteristic properties of engineered wood products B.1 General In some cases, the characteristic values of engineered wood products can be calculated from the characteristic properties of the individual elements from which it is assembled These models are f founded on the following principles s tati s tic a l ly b as e d and rely on the s hari ng o — s treng th b e twe en the elements T he s e mo del s are genera l ly T he glue j oi nt may b e re qui re d to b e a s s a s the ti mb er i n the engi ne ere d wo o d pro duc ts through the in-plant process control Otherwise, the model should consider the strength of the glue j oi nt i n add ition to the s treng th o f the ti mb er comp onent — B.2 T he prop er tie s o f engi ne ere d wo o d pro duc ts are en h ance d b y the placement o f comp onents i n different location or orientation based on the principle of engineering mechanics 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 engineered wood products are available from different countries or regions For example, ISO 22389-1 I-beams While some models are stochastic and the others are deterministic in nature, most models are f f this document contai n s an ana lytic a l mo del i n de term i ni ng the ch arac teri s tic moment c ap ac ity o f pre fabric ate d wo o d cap able o 10 pre d ic ti ng the cha rac teri s tic prop er ty va lue s o engi ne ere d wo o d pro duc ts comp atible with © ISO 2017 – All rights reserved ISO 2 -4: 01 7(E) Bibliography [1] [2] [3] ISO 12465, Plywood — Specifications ISO 16572, Timber structures — Wood-based panels — Test methods for structural properties ISO 16894, Wood-based panels — Oriented strand board (OSB) — Definitions, classification and [4] ISO 22389-1, Timber structures — Bending strength of I-beams — Part 1: Testing, evaluation and [5] [6] ISO 22390, Timber structures — Laminated veneer lumber — Structural properties ISO 22452, Timber structures — Structural insulated panel walls — Test methods specifications characterization © ISO 2017 – All rights reserved 11 ISO 12122-4:2017(E) I CS 91 080.2 Price based on 11 pages © ISO 2017 – All rights reserved