ASTM_D_6815_-_09_2015.pdf

Designation:D681509(Reapproved 2015)Standard Specification forEvaluation of Duration of Load and Creep Effects of Woodand Wood-Based Products1This standard is issued under the fixed designation D6815;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This specification provides a procedure for testing andevaluating duration of load and creep effects of wood andwood-based materials relative to an accepted duration of loadadjustment model.This specification was created for productsthat are currently covered by a consensus standard(forexample,lumber,structural composite lumber,and structural-use panels).This procedure is intended to demonstrate theengineering equivalence to the duration of load and creepeffects of visually graded lumber as specified in Practice D245for a product under evaluation used in dry service conditions.This procedure is not intended to evaluate the performance ofproducts under impact loading.Quantification of specificduration of load or creep factors is beyond the scope of thisspecification.For further guidance regarding the applicabilityof this specification refer to X1.1 in the Commentary.1.2 Use of the procedure in this specification to determineequivalence to the Practice D245 duration of load relationshipis limited to solid wood and wood-based products whose longterm load behavior is similar to that of solid wood.Equivalencedemonstrated in this specification is dependent upon evaluationof a products 90-day(minimum)creep-rupture performance.In this evaluation,three criteria must be satisfied:(1)adequatestrength over a 90-day period,(2)decreasing creep rate,and(3)limited fractional deflection.Asummary of the development ofthese criteria and the underlying assumptions behind them isprovided in the Commentary in Appendix X1 and AppendixX2.1.3 Long term degradation phenomena not described by acreep-rupture model are not addressed in this specification(seeCommentary X1.2.4).2.Referenced Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based Prod-uctsD198 Test Methods of Static Tests of Lumber in StructuralSizesD245 Practice for Establishing Structural Grades and Re-lated Allowable Properties for Visually Graded LumberD1037 Test Methods for Evaluating Properties of Wood-Base Fiber and Particle Panel MaterialsD2915 Practice for Sampling and Data-Analysis for Struc-tural Wood and Wood-Based ProductsD3043 Test Methods for Structural Panels in FlexureD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Based MaterialsD4761 Test Methods for Mechanical Properties of Lumberand Wood-Base Structural MaterialD5457 Specification for Computing Reference Resistance ofWood-Based Materials and Structural Connections forLoad and Resistance Factor DesignE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE177 Practice for Use of the Terms Precision and Bias inASTM Test Methods2.2 Other References:ANSI/AF&PA NDS-2005National Design Specification(NDS)for Wood Construction33.Terminology3.1 DefinitionsSee Terminologies D9 and E6 and Prac-tices E4 and E177 for definitions of terms used in thisspecification.1This specification is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.01 on Fundamental TestMethods and Properties.Current edition approved Sept.1,2015.Published October 2015.Originallyapproved in 2002.Last previous edition approved in 2009 as D6815-09.DOI:10.1520/D6815-09R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American Forest&Paper Association(AF&PA),AmericanWood Council,1111 19th Street NW,Suite 800,Washington,DC 20036,http:/www.afandpa.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2 Definitions of Terms Specific to This Standard:3.2.1 breadththe dimension of the test specimen in thedirection perpendicular to the span and perpendicular to thedirection of an applied bending load.3.2.2 creepthe time-dependent increase of deformation ofthe test material under a constant load.3.2.3 creep deflectiontotal measured deflection at a spe-cific time minus the initial deflection.3.2.4 creep ratethe change in creep deflection over time.3.2.5 creep-rupturea failure phenomenon described by arelationship between applied stress and time-to-failure.3.2.6 depththe dimension of the test specimen in thedirection perpendicular to the span and parallel to the directionof an applied bending load.3.2.7 dry service conditionsthe conditions in mos