1、Designation: D7989 18Standard Practice forDemonstrating Equivalent In-Plane Lateral SeismicPerformance to Wood-Frame Shear Walls Sheathed withWood Structural Panels1This standard is issued under the fixed designation D7989; the number immediately following the designation indicates the year oforigin
2、al 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 practice establishes a method for alternative shearwall syst
3、ems to compare seismic equivalency parameters(SEP) derived from cyclic in-plane racking tests to perfor-mance targets derived from tests of light-frame shear wallsconstructed with wood structural panel (WSP) sheathing at-tached to dimension lumber framing using nails.1.2 This practice considers only
4、 the performance of shearwalls subject to cyclic lateral loading, parallel to the plane ofthe shear wall. Design of walls with openings and performancefor other wall functions, such as out-of-plane bending, com-bined shear and uplift, and so forth are not considered.1.3 This practice is applicable o
5、nly to shear walls where allvertical-load-supporting elements are intact at the end of thein-plane lateral load test and remain capable of supportinggravity loads. Wall assemblies whose vertical-load-supportingelements buckle or otherwise become incapable of supportinggravity loads during the latera
6、l load test are outside the scopeof this practice. In addition, for bearing wall systems, thispractice assumes that the shear wall system under evaluationhas documented design procedures to ensure that vertical-load-supporting elements have adequate resistance to the combinedeffect of compression lo
7、ads caused by overturning and gravityloads.1.4 This practice does not address height limitations, detail-ing requirements, wall openings, derivation of design valuesfor strength and stiffness, or other requirements and limitationsthat may be necessary for an alternative shear wall system.These requi
8、rements shall be provided elsewhere, such as by asuitable product standard for the alternative shear wall system.1.5 This practice assumes that the stiffness or deformationof the alternative shear wall system can be estimated, and thatdesign loads within a structure will be distributed amongseismica
9、lly equivalent wall systems based on their relativestiffness.1.6 This practice is not intended to preclude other rationalmeans of evaluating seismic performance.1.7 This practice assumes that the alternative shear wallsystem may be used alone or in combination with wood-frameshear walls sheathed wit
10、h wood structural panels.1.8 UnitsThe values stated in inch-pound units are to beregarded as standard. The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard.1.9 This standard does not purport to address all of th
11、esafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.10 This international standard was developed in accor-dance with int
12、ernationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E21
13、26 Test Methods for Cyclic (Reversed) Load Test forShear Resistance of Vertical Elements of the Lateral ForceResisting Systems for BuildingsF1667 Specification for Driven Fasteners: Nails, Spikes, andStaples2.2 Other Documents:PS1-09 Structural Plywood, U.S. Department of CommerceVoluntary Product S
14、tandardPS2-10 Performance Standard for Wood-Based StructuralUse Panels, U.S. Department of Commerce VoluntaryProduct Standard1This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.05 on Wood Assemblies.Current edition approved Ju
15、ly 1, 2018. Published September 2018. Originallyapproved in 2015. Last previous edition approved in 2015 as D7989 15. DOI:10.1520/D7989-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
16、 information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standar
17、dization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13. Terminology3.1 DefinitionsThe definitions in Test Methods E2126also apply to this practi
18、ce.3.2 Definitions Specific to this Practice:3.2.1 aspect ratio, nratio of a shear walls height dividedby its length.3.2.2 allowable design load, nmaximum in-plane rackingresistance using an allowable stress design methodology as-signed to a tested shear wall configuration for seismic design.3.2.3 a
19、lternative shear wall system, nshear wall systemfor which seismic equivalence to the reference shear wallsystem is sought.3.2.3.1 DiscussionThe alternative shear wall system mayrepresent a range of possibilities including pre-fabricated orfield-fabricated wall assemblies that do not resemble therefe
20、rence shear wall system or assemblies with minor modifi-cations to the reference system, such as the use of alternativefasteners, framing, or sheathing.3.2.4 component overstrength, nratio of peak load dividedby allowable design load.3.2.5 drift capacity, nultimate cyclic displacement on theaverage
21、envelope curve defined in Test Methods E2126 corre-sponding to the failure limit state.3.2.6 ductility, nratio of drift capacity divided by thedisplacement on the average envelope curve defined in TestMethods E2126 corresponding to the allowable design load.3.2.7 peak load, nmaximum load on the aver
22、age envelopecurve defined in Test Methods E2126.3.2.8 reference shear wall system, nwood-frame shearwall system used for the equivalence benchmark, consisting ofwood structural panel sheathing attached to dimension lumberframing using 6d, 8d, or 10d common or box nails, with fullround heads, complyi
23、ng with Specification F1667, Section S1,Table S1.1, and Specification F1667, Table 6 or Table 15.3.2.8.1 DiscussionTable X1.1 provides summary informa-tion for the walls evaluated to represent the reference shearwall system.3.2.9 seismic equivalence parameters (SEP), nkey param-eters representing se
24、ismic performance of shear walls, specifi-cally drift capacity, component overstrength, ductility, andmaintenance of vertical-load-supporting capability.3.2.10 shear wall, nwall designed to resist lateral rackingshear forces parallel to the plane of the wall.3.2.11 shear wall configuration, nshear w
25、all of a specificheight and length representing one possible case of a shear wallsystem and consisting of a specific arrangement ofcomponents, such as framing, fasteners, sheathing, and anchor-age.3.2.12 wood structural panel (WSP)panel manufacturedin accordance with PS1 or PS2 from veneers; wood st
26、rands orwafers; or a combination of veneer and wood strands or wafers;bonded together with waterproof resins or other suitablebonding systems.4. Summary of Practice4.1 Shear walls are tested in accordance with Test MethodsE2126, and the average envelope curve is generated for eachspecimen as defined
27、 in 3.2.4 of Test Methods E2126.4.2 SEPs are determined from the average envelope curvefor each specimen, and the average SEPs for each tested shearwall configuration are compared to the benchmark parameters.4.3 Seismic equivalency is established if each of the SEPsfor the alternative shear wall sys
28、tem meets specified require-ments and the vertical-load-supporting elements are intact andcapable of supporting gravity loads.5. Significance and Use5.1 This practice documents cyclic performance bench-marks for shear walls constructed with wood structural panel(WSP) sheathing attached to dimension
29、lumber framing usingcommon or box nails as defined in 3.2.8.5.2 Procedures described in this practice provide a methodto evaluate an alternative shear wall systems SEPs to demon-strate equivalent in-plane lateral seismic performance to thereference shear wall system.5.3 The procedures described in t
30、his practice do not addressall factors to be considered for recognition of an alternativeshear wall system. Such factors, as described in 1.4, vary by theend-use application and shall be addressed outside the scope ofthis standard through an evaluation of the acceptability of thealternative shear wa
31、ll system in accordance with requirementsof building codes and standards, as applicable.6. Testing Requirements6.1 Test Program DesignThe test program used to evalu-ate the alternative shear wall system shall be based onconsideration of the range of intended applications and vari-ables that have a p
32、otential impact on the seismic performance.Variables may include, but are not limited to, allowable designloads, configuration options, material variations, fastenerspacings, and aspect ratios.6.2 Number of TestsFor each tested shear wallconfiguration, the number of replicates shall be as required i
33、n8.1 of Test Methods E2126 or as required by the applicableproduct standard.6.3 LoadingCyclic lateral load tests shall be conductedusing Method C from Test Methods E2126.6.3.1 Load BeamThe load beam used to apply load to thetest assembly shall comply with 7.3 of Test Methods E2126.6.4 Rigid BaseTest
34、ing shall be conducted on a rigid base,such that the performance of the test specimens is not influ-enced by deformation of the base structure. The specimensshall be anchored directly to the base and shall be in fullcontact with the base.6.5 Test Specimen ConstructionSpecimens shall be con-structed
35、using details consistent with the intended application.Sheathing, if present, shall not bear on any portion of the testfixture or the loading beam during the tests, except where thespecified end-use installation requires the sheathing to bear onD7989 182supporting elements, such as foundations or si
36、ll plates. Ifbearing on a wood sill plate is specified in application, a similarwood sill plate shall be included in the tested assembly.6.5.1 Aspect RatiosAspect ratios and wall dimensionsshall be consistent with the intended application.6.5.1.1 Alternative shear wall systems that are similar to th
37、ereference system (that is, repetitive vertical stud framingspaced at 24 in. on center or less with structural sheathingnailed to framing), except for variations in framing materials,sheathing materials, or fasteners, shall be evaluated using anaspect ratio of 1:1 and a minimum wall height of 8 ft (
38、2.4 m).6.5.1.2 Alternative shear wall systems that vary more sig-nificantly from the reference system described in 6.5.1.1 shallbe evaluated using the range of aspect ratios for the intendedapplication.6.5.2 Sheathing JointsAlternative shear wall systems thatwill include discrete sheathing panels sh
39、all include at least onevertical sheathing joint if such joints will occur in application.Test specimens may include horizontal sheathing joints asnecessary, such as where specimen heights exceed panel heightor where sheathing is intended to be installed with the longdimension perpendicular to the l
40、ongitudinal axis of the studs.6.5.3 FramingWhere applicable, the stud and platematerial, species, grade, size, and spacing shall be representa-tive of that used in application. Framing shall meet therequirements of 6.3 in Test Methods E2126.6.5.3.1 For alternative systems described in 6.5.1.1, frami
41、ngwith the smallest standard stud and plate cross sectionsexpected in application shall be used, and the smallest numberof end post studs that can practically be employed in accor-dance with standard design provisions shall be used.6.5.4 Anchorage and Framing ConnectionsShearanchorage, overturning r
42、estraint, and framing connections,including connections between individual plies of built-upposts, shall be representative of connections used in applicationand shall be designed and detailed to balance the designresistance of the connections to the design load of the shearwall.6.5.5 Sheathing Conne
43、ctionsWhere sheathing attached toframing is used to resist lateral loads, the sheathing fastenersshall be installed using the minimum edge distance recom-mended by the sheathing manufacturer along all four sheathingedges. The number of fasteners installed along each edge shallbe equal to the length
44、of the sheathing edge divided by thespecified fastener spacing, plus one. Spacing between thesheathing corner fastener and the next adjacent fastener ispermitted to be less than the recommended spacing to accom-modate the required edge distance. Sheathing fasteners placedin the field of the panel, i
45、f any, shall be positioned as requiredby the design. Sheathing fasteners shall be driven so that thehead of the fastener contacts the surface of the sheathing, butnot so deep as to crush the surface, unless specified differentlyby the manufacturer.7. Evaluation of Cyclic Response7.1 Average Envelope
46、 CurveThe average envelope curveshall be generated for each test specimen as defined in 3.2.4 ofTest Methods E2126.7.2 SEP DeterminationThe component overstrength, driftcapacity, and ductility shall be determined for each specimenas defined in 3.2. The average values calculated for allreplicates of
47、a tested shear wall configuration shall be the SEPsfor the alternative shear wall configuration. The results ofmultiple shear wall configurations shall not be averaged orotherwise combined for the evaluation.7.3 Assessment of Vertical-Load-Supporting ElementsThecondition of the vertical-load-support
48、ing elements shall bevisually assessed to qualitatively determine whether the capa-bility to support gravity loads is retained.NOTE 1Visual assessment of vertical-load-supporting elements relieson examination during and after the test for observation of occurrence ofbuckling of the vertical-load-sup
49、porting elements. For wood-frame wallsthat comprise the reference shear wall system, the lack of observedbuckling of the studs and end posts has been used as visual confirmationof retained ability to support gravity loads.8. Requirements for Equivalency8.1 Table 1 provides the SEP performance targets based ontests of the reference shear wall system conducted in accor-dance with Method C of Test Methods E2126.8.2 Seismic equivalency is established if the SEPs for thealternative shear wall system meet requirements specified inTable 1 and if the vertica
