1、Designation: D5457 17D5457 18Standard Specification forComputing Reference Resistance of Wood-Based Materialsand Structural Connections for Load and Resistance FactorDesign1This standard is issued under the fixed designation D5457; the number immediately following the designation indicates the year
2、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.INTRODUCTIONLoad and resistance factor design (LRFD) is a structural
3、design method that uses concepts fromreliability theory and incorporates them into a procedure usable by the design community. The basicdesign equation requires establishing a reference resistance based on several material propertyparameters. A standard method for calculating the required material p
4、roperty input data is critical sothat all wood-based structural materials can be treated equitably. This specification provides theprocedures that are required for the generation of reference resistance for LRFD.1. Scope1.1 This specification covers procedures for computing the reference resistance
5、of wood-based materials and structuralconnections for use in load and resistance factor design (LRFD). The format conversion procedure is outlined in Section 4. Thetest-based derivation procedure is outlined in Annex A1. The reference resistance derived from this specification applies to thedesign o
6、f structures addressed by the load combinations in ASCE 7-10.7-16.1.2 A commentary to this specification is provided in Appendix X1.1.3 UnitsThe values stated in inch-pound units are to be regarded as the standard. The values given in parentheses aremathematical conversions to SI units that are prov
7、ided for information only and are not considered standard.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issu
8、edby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based ProductsD143 Test Methods for Small Clear Specimens of TimberD198 Test Methods of Static Tests of Lumber in Structural SizesD1037 Te
9、st Methods for Evaluating Properties of Wood-Base Fiber and Particle Panel MaterialsD1761 Test Methods for Mechanical Fasteners in WoodD1990 Practice for EstablishingAllowable Properties for Visually-Graded Dimension Lumber from In-Grade Tests of Full-SizeSpecimensD2718 Test Methods for Structural P
10、anels in Planar Shear (Rolling Shear)D2719 Test Methods for Structural Panels in Shear Through-the-ThicknessD2915 Practice for Sampling and Data-Analysis for Structural Wood and Wood-Based ProductsD3043 Test Methods for Structural Panels in Flexure1 This specification is under the jurisdiction ofAST
11、M Committee D07 on Wood and is the direct responsibility of Subcommittee D07.02 on Lumber and Engineered WoodProducts.Current edition approved Nov. 1, 2017Nov. 1, 2018. Published December 2017December 2018. Originally approved in 1993. Last previous edition approved in 20152017as D5457 15.D5457 17.
12、DOI: 10.1520/D5457-17.10.1520/D5457-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not a
13、n ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate.
14、In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D3500 Test Methods for Structural Panels in TensionD3501 Test Methods
15、for Wood-Based Structural Panels in CompressionD3737 Practice for Establishing Allowable Properties for Structural Glued Laminated Timber (Glulam)D4761 Test Methods for Mechanical Properties of Lumber and Wood-Base Structural MaterialD5055 Specification for Establishing and Monitoring Structural Cap
16、acities of Prefabricated Wood I-JoistsD5456 Specification for Evaluation of Structural Composite Lumber ProductsE105 Practice for Probability Sampling of Materials2.2 ASCE Standard:3ASCE 7-107-16 Minimum Design Loads and Associated Criteria for Buildings and Other Structures3. Terminology3.1 Definit
17、ions:3.1.1 For general definitions of terms related to wood, refer to Terminology D9.3.2 Definitions of Terms Specific to This Standard:3.2.1 ASD reference design value, Fxthe design value at reference conditions used in allowable stress design (ASD) prior toapplication of the load duration factor (
18、CD).3.2.2 coeffcient of variation, CVwa relative measure of variability based on the shape parameter of the 2-parameter Weibulldistribution.3.2.2.1 DiscussionIt is not the traditional sample standard deviation of the data divided by the sample mean.3.2.3 data confidence factor, a factor that is used
19、 to adjust member reference resistance for sample variability and samplesize.3.2.4 distribution percentile, Rpthe value of the distribution associated with proportion, p, of the cumulative distributionfunction.3.2.5 factored resistance, Rresistancenthe product of the resistance factor () and the ref
20、erence or nominal resistancenot(Rn including the time effect factor () and other adjustments for end-use conditions.).3.2.6 format conversion factor, KFa factor applied to convert resistance from the allowable stress design (ASD) format to theLRFD format.format, equal to the ratio Rn / Fx.3.2.7 lowe
21、r taila portion of an ordered data set consisting of all test specimens with the lowest property values (for example,lowest strengths).3.2.8 nominal resistancea term equivalent to the reference resistance used in reliability analysis and LRFD standards.3.2.9 reference conditionsthe design basis for
22、which all applicable adjustment factors are equal to unity, except for the loadduration factor in ASD or the time effect factor in LRFD.3.2.10 reference resistance, Rnthe design value at reference conditions used in LRFD equations to represent memberresistance prior to application of the resistance
23、factor, factor () and the time effect factor (), and other adjustments for end-useconditions.().3.2.10.1 DiscussionThe reference value represents member resistance at 10-minute load duration.3.2.11 reliability normalization factor, KRa factor used to establish the reference resistance to achieve a t
24、arget reliability indexfor a reference set of conditions.3.2.12 resistance factor, a factor applied to the resistance side of the LRFD equation.4. Reference Resistance for LRFD4.1 Reference resistance for LRFD shall be determined using one of the following procedures:4.1.1 Format conversion per Sect
25、ion 4.2; or4.1.2 Test-based derivation per Annex A1.4.2 Format Conversion Procedure:3 Available from The American Society of Civil Engineers (ASCE), 1801 Alexander Bell Dr., Reston, VA 20191.D5457 1824.2.1 Resistance values for LRFD are permitted to be based on format conversion from code-recognized
26、 allowable stress design(ASD). It shall not be claimed that reference resistance values generated in this manner achieve a stated reliability index.Resistance factors for determining LRFD factored resistance, Rn, are given in Table 1.NOTE 1Examples of standards that are used to generate code-recogni
27、zed ASD values include Test Methods D143, D198, D1037, D1761, D2718,D2719, D3043, D3500, D3501, and D4761; Practices D1990 and D3737; and Specifications D5055 and D5456.4.2.2 For standardization purposes, format conversion reference resistance values shall be based on the arithmetic conversionat a s
28、pecified reference condition that results from the calibration (defined as providing an identical required section modulus,cross-sectional area, allowable load capacity, and so forth) of basic ASD and LRFD equations. The specified reference conditionshall be chosen such that changes in design capaci
29、ty over the range of expected load cases and load ratios is minimized.4.2.3 Values of the format conversion factor, KF, are given in Table 2.4.2.4 The format conversion reference resistance is computed by multiplying the ASD resistance by KF. For members andconnections, theASD resistance is based on
30、 a normal (10-year) load duration. For shear walls and diaphragms, theASD resistanceis based on a 10-minute load duration.4.2.5 For lateral buckling (stability), compression perpendicular to grain, and rolling shear that is not subject to load durationor time effect adjustments, the value of KF is b
31、ased on the assumption that neither the ASD nor LRFD resistance values aremodified by duration of load or time effect adjustments.4.2.6 Format Conversion ExampleAn ASD bolt design value for a single shear connection, Fx, is 800 lbf (3.56 kN) (basedon normal 10-year load duration). From Table 2, the
32、format conversion factor, KF, is 3.32. The corresponding LRFD bolt referenceresistance value is as follows:Rn 5KF 3Fx 53.32380052658 lbf 11.82 kN! (1)4.2.7 Format Conversion Example for Shear Walls or DiaphragmsAn ASD shear wall design value, Fx, is 395 lb/ft (5.76kN/m) (based on a 10-minute load du
33、ration). From Table 2, the format conversion factor, KF, is 2.00. The corresponding LRFDshear wall reference resistance value is as follows:Rn 5KF 3Fx 52.0033955790 lbft 11.53 kN/m! (2)5. Keywords5.1 format conversion; load and resistance factor design (LRFD); reference resistance; structural connec
34、tions; test-basedderivation; wood-based materialsTABLE 1 Specified LRFD Resistance Factors, sApplication Property sMembers compressionA 0.90bending, lateral buckling (stability) 0.85tension parallel 0.80shear, radial tension 0.75Connections all 0.65Shear Walls, diaphragms shear 0.80A Compressionpara
35、llel-to-grain,compressionperpendicular-to-grain,andbearing.D5457 183ANNEX(Mandatory Information)A1. TEST-BASED DERIVATION OF REFERENCE RESISTANCE FOR LRFDA1.1 Parameters required for the derivation of reference resistance are presented in this Annex. These parameters include thedistribution percenti
36、le, Rp, coefficient of variation, CVw, data confidence factor, , and reliability normalization factor, KR. Anexample derivation of reference resistance is provided in X1.8.5.A1.2 Sampling:A1.2.1 Samples selected for analysis and implementation with this specification shall be representative of the p
37、opulation aboutwhich inferences are to be made. Both manufacturing and material source variability shall be considered. The principles of PracticeE105 shall be maintained. Practice D2915 provides methods for establishing a sampling plan. Special attention is directed tosampling procedures in which t
38、he variability is low and results can be influenced significantly by manufacturing variables. It isessential that the sampling plan addresses the relative magnitude of the sources of variability.A1.2.1.1 Data generated from a quality control program shall be acceptable if the criteria of A1.2.1 are
39、maintained.A1.2.1.2 Multiple Data SetsWhen data from multiple data sets are compiled or grouped, the criteria used to group such datashall be in accordance with the provisions of A1.2.1. When such procedures are available in applicable product standards, theyshall be used.A1.2.2 Sample Size:A1.2.2.1
40、 For data sets in which all specimens are tested to failure, the minimum sample size shall be 30.NOTE A1.1The confidence with which population properties can be estimated decreases with decreasing sample size. For sample sizes less than 60,extreme care must be taken during sampling to ensure a repre
41、sentative sample.A1.2.2.2 For lower tail data sets, a minimum of 60 failed observations is required for sample sizes of n = 600 or less. Thisrepresents at least the lower 10 % of the distribution. For sample sizes greater than 600, a minimum of the lowest 10 % of thedistribution is required. For exa
42、mple, sample size, n = 720, 0.10 (720) = 72 failed test specimens in the lower tail. Only parameterestimation procedures designed specifically for lower tail data sets shall be used (see Appendix X2).A1.3 Testing:TABLE 2 Format Conversion Factor, KFProperty KFCompression Parallel to Grain 2.40Bendin
43、g 2.54Tension Parallel to Grain 2.70Shear 2.88ARadial Tension 2.88Connections 3.32Lateral Buckling (Stability) 1.76Compression Perpendicular to Grain 1.67Shear Wall and Diaphragm Shear 2.00BA The value of the format conversion factor is 2.00 where shear is not subject toload duration or time effect
44、adjustments (e.g., rolling shear in cross-laminatedtimber).B The format conversion factor for shear wall and diaphragm shear is only intendedto be applied to the design capacity of shear wall or diaphragm assemblies, not tothe design of individual members or subcomponents of these assemblies.D5457 1
45、84A1.3.1 Testing shall be conducted in accordance with appropriate standard testing procedures. The intent of the testing shall beto develop data that represent the capacity of the product under standard conditions.A1.3.2 Periodic Property AssessmentPeriodic testing is recommended to verify that the
46、 properties of production material remainrepresentative of published properties.A1.4 Reference Resistance, RnThe following equation establishes reference resistance for LRFD:Rn 5Rp 33KR (A1.1)where:Rp = distribution percentile estimate, = data confidence factor, andKR = reliability normalization fac
47、tor.A1.4.1 Distribution Percentile Estimate, Rp:A1.4.2 EqA1.2 is intended to be used to calculate any percentile of a two-parameterWeibull distribution.The percentile of interestdepends on the property being estimated.Rp 5-ln 1 2 p!#1 (A1.2)where: = Weibull scale parameter,p = percentile of interest
48、 expressed as a decimal (for example, 0.05), and = Weibull shape parameter.A1.4.3 The shape () and scale () parameters of the two-parameter Weibull distribution shall be established to define thedistribution of the material resistance (1).4 Algorithms for common estimation procedures are provided in
49、 Appendix X2.A1.4.4 Coeffcient of Variation, CVwThe coefficient of variation of the material is necessary when determining the dataconfidence factor, , and the reliability normalization factor, KR. The CVw can be estimated from the shape parameter of theWeibull distribution as follows:CVw20.92 (A1.3)NOTE A1.2The above approximation is within 1 % of the exact solution for CVw values between 0.09 and 0.50. An exact relationship of CVw and is shown in Appendix X3.A1.5 Data Confidence Factor, The data confidence factor,
