1、Designation: E2126 11Standard Test Methods forCyclic (Reversed) Load Test for Shear Resistance of VerticalElements of the Lateral Force Resisting Systems forBuildings1This standard is issued under the fixed designation E2126; the number immediately following the designation indicates the year oforig
2、inal 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 These test methods cover the evaluation of the shearstiffness,
3、shear strength, and ductility of the vertical elementsof lateral force resisting systems, including applicable shearconnections and hold-down connections, under quasi-staticcyclic (reversed) load conditions.1.2 These test methods are intended for specimens con-structed from wood or metal framing bra
4、ced with solidsheathing or other methods or structural insulated panels.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This stan
5、dard does not purport to address all of thesafety 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.2. Referenced Documents2.1 A
6、STM Standards:2D2395 Test Methods for Specific Gravity of Wood andWood-Based MaterialsD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base MaterialsD4444 Test Method for Laboratory Standardization andCalibration of Hand-Held Moisture MetersE564 Practice for Static Load T
7、est for Shear Resistance ofFramed Walls for BuildingsE575 Practice for Reporting Data from Structural Tests ofBuilding Constructions, Elements, Connections, and As-sembliesE631 Terminology of Building Constructions2.2 ISO Standard:3ISO 16670 Timber StructuresJoints Made with Mechani-cal FastenersQua
8、si-static Reversed-cyclic Test Method2.3 Other Standards:4ANSI/AF the negativespecimen displacement produces a negative envelope curve.The positive direction is based on outward movement of thehydraulic actuator.3.2.4 envelope curve, average (see Fig. 3), nenvelopecurve obtained by averaging the abs
9、olute values of load anddisplacement of the corresponding positive and the negativeenvelope points for each cycle.3.2.5 equivalent energy elastic-plastic (EEEP) curve (see9.1.4, Fig. 1), nan ideal elastic-plastic curve circumscribing1These test methods are under the jurisdiction of ASTM Committee E0
10、6 onPerformance of Buildings and are the direct responsibility of Subcommittee E06.11on Horizontal and Vertical Structures/Structural Performance of Completed Struc-tures.Current edition approved May 1, 2011. Published May 2011. Originallyapproved in 2001. Last previous edition approved in 2010 as E
11、2126 10. DOI:10.1520/E2126-11.2For 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 International O
12、rganization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.4Available from American Forest and Paper Association (AF moisturecontent of the framing members at the time of the specimenfabrication and testing, if more than 24 h pa
13、sses between theseoperations (see Test Methods D4442, Test Methods A or B; orD4444, Test Methods A or B); and specific gravity of theframing members (see Test Methods D2395, Test Method A).The specific gravity of the framing members shall be repre-sentative of the published specific gravity for the
14、product withno individual member exceeding the published value by morethat 10 % (see ANSI/AF andL = length of specimen, ft (m).9.1.2 Secant shear modulus, G8,at0.4Ppeakand at Ppeakshall be calculated as follows:G8 5PD3HL(2)where:G8 = shear modulus of the specimen obtained from test(includes shear an
15、d uplift deformation for the connec-tion system), lbf/in. (N/m); represents the secant shearstiffness at specified specimen displacements timesthe aspect ratio;P = applied load measured at the top edge of the speci-men, lbf (N);D = displacement of the top edge of the specimen based ontest, in. (m).
16、This includes both the shear deflection ofthe sheathing material and its connections, and thecontribution of the shear and hold-down connectionsystems;H = height of specimen, ft (m); andL = length of specimen, ft (m).9.1.3 Cyclic ductility ratio, D, as described in 3.2.1, shall becalculated. If the
17、shear stiffness (shear modulus) at 0.4 Ppeakisgreater than that at Ppeak, generate the EEEP curve as describedin 9.1.4. Otherwise, the FME and the ultimate displacementshall be determined directly from the envelope curve. Calculatevalues of displacement, shear forces, and shear modulus at theyield l
18、imit state and strength limit state.9.1.4 When specified by 9.1.3, develop an EEEP curve torepresent the envelope curve. Fig. 1 illustrates typical EEEPcurve. The elastic portion of the EEEP curve contains theorigin and has a slope equal to the elastic shear stiffness, Ke.The plastic portion is a ho
19、rizontal line equal to Pyielddeter-mined by the following equation:Pyield5 SDu2Du222AKeD Ke(3)If Du2,2AKe, it is permitted to assume Pyield5 0.85 Ppeakwhere:Pyield= yield load, lbf (N);A = the area under envelope curve from zero to ulti-mate displacement (Du) of the specimen, lbfin.(Nm);TABLE 3 Test
20、 Method CAmplitude of Primary CyclesPattern StepMinimum Numberof CyclesAmplitude of PrimaryCycle, % D11 6 522 7 7.37 1034 4 254 346 3 4073 78 3 1009 3 100 + 100aA10 3 Additional increments of100a (until specimen failure)Aa # 0.5.E2126 1111Ppeak= maximum absolute load resisted by the specimenin the g
21、iven envelope, lbf (N);De= displacement of the top edge of the specimen at0.4 Ppeak, in. (mm); andKe= 0.4 Ppeak/De.9.1.4.1 To generate an EEEP curve as described in 8.3.2based on monotonic test results, the procedures in this sectionare permitted, with Dmsubstituting for Du.9.1.5 If the envelope cur
22、ve contains data points at loads lessthan |0.8 Ppeak| (past strength limit state), the failure limit stateshall be determined at 0.8 Ppeakusing linear interpolation, asillustrated in Fig. 1.10. Report10.1 The report shall include the following information:10.1.1 Date of the test and of report.10.1.2
23、 Names of the test sponsors and test agency and theirlocations.10.1.3 Identification of the specimen (test number, and soforth).10.1.4 Detailed description of the specimen and the testsetup, including the following:10.1.4.1 Dimensions of the specimen.10.1.4.2 Details of the physical characteristics
24、or structuraldesign, or both, of the specimen, including, if applicable, thetype, spacing, and edge distance of fasteners attaching sheath-ing to framing.10.1.4.3 Details of attachment of the specimen in the testfixture, including a description of the test base and whethersheathing panels are direct
25、ly bearing on the sill plate duringtesting.10.1.4.4 Location of load application and load cell, straingauges, deflection gauges, and other items for test as appli-cable.10.1.4.5 Description of construction materials (for example,material type and grade, thickness, yield point, tensile strength,compr
26、essive strength, density, moisture content, manufacturerof components used, source of supply, dimensions, model,type, and other pertinent information, and so forth, as appro-priate for materials used).10.1.4.6 Drawing showing plan, elevation, principal crosssection, and other details as needed for d
27、escription of thespecimen and the test setup (see 10.1.4.1-10.1.4.5).10.1.4.7 Description of general ambient conditions includ-ing the following:(1) At construction;(2) During curing or seasoning, if applicable (includingelapsed time from construction to test); and(3) At test.10.1.4.8 Modifications
28、made on the specimen during test-ing.10.1.4.9 Description of any noted defects existing in thespecimen prior to test.10.1.5 Description of the test, including a statement that thetest or tests were conducted in accordance with this test methodor otherwise describing any deviations from the test meth
29、od.10.1.6 Summary of results, including:10.1.6.1 Hysteresis loops (applied load versus displacementat the top of the specimen) for every specimen tested.10.1.6.2 Complete record (table or plot) of individual dis-placements required to be measured in 8.7.10.1.6.3 Shear strength (npeak) from tests of
30、identical speci-mens (9.1.1).10.1.6.4 As-tested and mean values of P, D and G8 at yieldlimit state and strength limit state in accordance with Section 9.10.1.6.5 EEEP curve developed from the mean loads anddisplacements at yield limit state and failure limit state, ifapplicable (see 9.1.3 and 9.1.4)
31、.10.1.7 Description of failure modes and any behaviorchange and significant events, for each test.10.1.8 Photographs of the specimen, particularly those de-picting conditions that cannot otherwise be easily described inthe report text, such as failure modes and crack patterns.10.1.9 Appendix (if nee
32、ded) that includes all data notspecifically required by test results. Include special observa-tions for building code approvals.10.1.10 Signatures of responsible persons are in accordancewith Practice E575.11. Precision and Bias11.1 No statement on the precision and bias is offered due tothe numerou
33、s individual elements that comprise the specimenand the small number of replicate specimens tested. A gener-ally accepted method for determining precision and bias iscurrently unavailable.12. Keywords12.1 cyclic loads; earthquake; framed walls; lateral-forceresisting systems; portal frames; racking
34、loads; rigid support;shear displacement; shear stiffness; shear strength; structuralinsulated panelsE2126 1112APPENDIXES(Nonmandatory Information)X1. DETERMINATION OF FIRST MAJOR EVENTX1.1 The FME is the first significant limit state that occursduring the test. The limit state in turn denotes an eve
35、nt markingphase change between two behavior states. As noted in 8.3.2,the FME can be determined from monotonic load tests on anidentical specimen. If the first estimate is inappropriate, thedata obtained can be revised for the subsequent tests. Thefollowing estimates offer guidance for a typical 8-f
36、t (2.4-mm)wall.X1.1.1 Wood-Framed Walls with Wood Structural PanelSheathingAspect ratios of 2:1 or less, FME = 0.8 in. (20mm); aspect ratio of 4:1, FME = 1.2 in. (31 mm).X1.1.2 Wood-Framed Walls with Gypsum SheathingAspect ratios of 2:1 or less, FME = 0.25 in. (6.4 mm).X2. SELECTION OF CYCLING METHO
37、DX2.1 Test Method A Versus Test Method BX2.1.1 Test Method A:X2.1.1.1 Test MethodAis a sequential phased displacementpattern that exhibits decay cycles between the steps in theloading pattern. These decay cycles provide information onwhether there is a lower bound in displacement required toproduce
38、hysteretic energy dissipation (1).5An example wherea lower bound displacement causing hysteretic energy dissipa-tion may occur would be a bolted connection through anover-drilled hole.X2.1.1.2 Test Method A is based on Ref (2), which wasdeveloped by the Structural Engineers Association of SouthernCa
39、lifornia (SEAOSC) to test wood or steel framed shear wallsfor earthquake resistance. The Ref (2) is currently not beingmaintained. There is a considerable breadth of information andvast databases on walls tested under Ref (2). For the purposesof acceptance testing it would be permissible to correlat
40、e theresults of the two test methods.X2.1.2 Test Method B:X2.1.2.1 The cyclic protocol for Test Method B was devel-oped for ISO 16670, a method for testing mechanically fas-tened timber joints. The background for this standard is givenin Ref (3-6), which indicates that a unique cyclic displacementor
41、 loading history will always be a compromise, but one that isconservative for most practical cases should be selected. TheTest Method B test protocol is intended to produce data thatsufficiently describe elastic and inelastic cyclic properties; andtypical failure mode that is expected in earthquake
42、loading.X2.1.3 Selection of Test Method A Versus Test Method B:X2.1.3.1 Test Method A may be applicable to systems whenFME is the yield limit state or for testing slack systems todetermine a lower bound displacement causing hystereticenergy dissipation. Test Method B is a ramped displacementphase th
43、at bases the cycles on the percentage of an ultimatedisplacement determined through static tests. Test Method Bmay be more applicable to systems that exhibit linear elasticbehavior where FME is the strength limit state. If the ratio ofDmand FME is less than three, Test Method B may bepreferable. Bot
44、h test methods are intended to generate similardisplacement amplitudes in order to obtain similar number ofpoints in the envelope curves. The difference is the number ofcycles in each phase (step).X2.2 Test Method CX2.2.1 Test Method C (CUREE protocol) is the latestaddition to the family of cyclic t
45、est protocols. It was developedbased on the statistical analysis of seismic demands onlight-frame buildings representative of California (in particularLos Angeles) conditions. The CUREE basic loading history isa realistic and conservative representation of the cyclic defor-mation history to which a
46、component of a wood structure likelyis subjected in earthquakes (7, 8). At relatively large deforma-tions (primary cycles exceeding an amplitude of 0.4 D), theamplitude of the primary cycles increases by large steps. Theselarge steps are based on statistics of inelastic time historyresponses. If the
47、 purpose of the experiment is acceptancetesting, then it is permissible to reduce the step size of theprimary cycles with large amplitudes. Smaller step sizes closeto failure may result in a larger capacity (largest amplitude atwhich the acceptance criteria are met), even though they willresult in l
48、arger cumulative damage. The reason is that the largestep sizes of the basic loading history permit evaluation ofacceptance only at discrete and large amplitude intervals. Thisstandard permits a reduction in step size only for phases inwhich the amplitude of the primary cycle exceeds D. In thatregim
49、e the amplitude the primary cycle may be increased byaD, with a to be chosen by the user, but a #0.5.X2.2.2 The reference deformation, D, is a measure of thedeformation capacity (Du) of the specimen when subjected tothe cyclic loading history. It is used to control the loadinghistory, and therefore needs to be estimated prior to the test.The estimate can be based on previous experience, the resultsof a monotonic test, or a consensus value that may prove to beuseful for comparing tests of different details or configurations.In CUREE Project (7), the following guidelines we
