ASTM E2126-2007a Standard Test Methods for Cyclic (Reversed) Load Test for Shear Resistance of Vertical Elements of the Lateral Force Resisting Systems for Buildings.pdf

1、Designation: E 2126 07aStandard 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 E 2126; the number immediately following the designation indicates the year ofo

2、riginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the evaluation of the shearstiffne

3、ss, 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

4、 braced 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

5、standard 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

6、.1 ASTM Standards:2D 2395 Test Methods for Specific Gravity of Wood andWood-Based MaterialsD 4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base MaterialsD 4444 Test Methods for Use and Calibration of Hand-HeldMoisture MetersE 564 Practice for Static Load Test for Shear

7、Resistance ofFramed Walls for BuildingsE 575 Practice for Reporting Data from Structural Tests ofBuilding Constructions, Elements, Connections, and As-sembliesE 631 Terminology of Building Constructions2.2 International Organization for Standardization Stan-dard:ISO 16670:2003 Timber StructuresJoint

8、s Made with Me-chanical FastenersQuasi-static Reversed-cyclic TestMethod33. Terminology3.1 For definitions of terms used in this standard, seeTerminology E 631.3.2 Definitions of Terms Specific to This Standard:3.2.1 ductility ratio, cyclic (D), nthe ratio of the ultimatedisplacement (Du) and the yi

9、eld displacement (Dyield)ofaspecimen observed in cyclic test.3.2.2 elastic shear stiffness (Ke) (see 9.1.4, Fig. 2), ntheresistance to deformation of a specimen in the elastic rangebefore the first major event (FME) is achieved, which can beexpressed as a slope measured by the ratio of the resisted

10、shearload to the corresponding displacement.3.2.3 envelope curve (see Fig. 1), nthe locus of extremi-ties of the load-displacement hysteresis loops. The envelopecurve contains the peak loads from the first cycle of each phaseof the cyclic loading. Specimen displacement in the positivedirection produ

11、ces a positive envelope curve; the negativespecimen displacement produces a negative envelope curve.The positive direction is based on outward movement of thehydraulic actuator.3.2.4 equivalent energy elastic-plastic (EEEP) curve (see9.1.4, Fig. 2), nan ideal elastic-plastic curve circumscribingan a

12、rea equal to the area enclosed by the envelope curvebetween the origin, the ultimate displacement, and the dis-placement axis. For monotonic tests, the observed load-displacement curve is used to calculate the EEEP curve.3.2.5 failure limit state, nthe point on the envelope curvecorresponding to the

13、 last data point with the absolute loadequal or greater than |0.8 Ppeak|, as illustrated in Fig. 2a.3.2.6 failure load (Pu), nthe load corresponding to thefailure limit state.1These test methods are under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and are the direct responsibi

14、lity of Subcommittee E06.11on Horizontal and Vertical Structures/Structural Performance of Completed Struc-tures.Current edition approved Dec. 1, 2007. Published January 2008. Originallyapproved in 2001. Last previous edition approved in 2007 as E 2126 072For referenced ASTM standards, visit the AST

15、M 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 National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036

16、, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.FIG. 1 Examples of Observed Hysteresis Curve and Envelope Curves for Method AFIG. 1 Examples of Observed Hysteresis Curve and Envelope Curves for Method B (continue

17、d)E 2126 07a23.2.7 first major event (FME), nthe first significant limitstate to occur (see limit state).3.2.8 limit state, nan event that demarks the two behaviorstates, at which time some structural behavior of the specimenis altered significantly.3.2.9 specimen, nthe vertical element of the later

18、al forceresisting system to be tested. Example of specimens are walls,structural insulated panels, portal frames, etc. A specimen canbe a single element or an entire line of resistance within alateral force resisting system.3.2.10 stabilized response, nload resistance that differsnot more than 5 % b

19、etween two successive cycles at the sameamplitude.3.2.11 strength limit state (see Fig. 2), nthe point on theenvelope curve corresponding to the maximum absolute dis-placement Dpeakat the maximum absolute load (Ppeak) resistedby the specimen.3.2.12 ultimate displacement, cyclic (Du), nthe displace-m

20、ent corresponding to the failure limit state in cyclic test.3.2.13 ultimate displacement, monotonic (Dm), nthe dis-placement corresponding to the failure limit state in monotonictest.3.2.14 yield limit state, nthe point in the load-displacement relationship where the elastic shear stiffness ofthe as

21、sembly decreases 5 % or more. For specimens withnonlinear ductile elastic response, the yield point (Dyield, Pyield)is permitted to be determined using the EEEP curve (see 9.1.4).4. Summary of Test Method4.1 The elastic shear stiffness, shear strength and ductility ofspecimens are determined by subj

22、ecting a specimen to full-reversal cyclic racking shear loads. This is accomplished byanchoring the bottom edge of the specimen to a test basesimulating intended end-use applications and applying a forceparallel to the top of the specimen. The specimen is allowed todisplace in its plane. Sheathing p

23、anels that are a component ofa specimen shall be positioned such that they do not bear on thetest frame during testing. (See Note 1) As the specimen isracked to specified displacement increments, the racking(shear) load and displacements are continuously measured (see8.7).NOTE 1If the end-use applic

24、ations require sheathing panels beardirectly on the sill plate, such as most structural insulated panels, thespecimen may be tested with sheathing panels that bear on the sill plate.5. Significance and Use5.1 These test methods are intended to measure the perfor-mance of vertical elements of the lat

25、eral force resisting systemsubjected to earthquake loads. Since these loads are cyclic, theloading process simulates the actions and their effects on thespecimens.6. Specimen6.1 GeneralThe typical specimen consists of a frame,bracing elements, such as panel sheathing, diagonal bracing,FIG. 1 Example

26、s of Observed Hysteresis Curve and Envelope Curves for Method C (continued)E 2126 07a3etc., and fastenings. The bracing is attached on one side of theframe unless the purpose of the test requires bracing on bothsides. The elements of the specimen shall be fastened to theframe in a manner to conform

27、to 6.2. Elements used toconstruct specimens may be varied to permit anticipated failureof selected elements. All structural detailing shall be clearlyidentified in the report in accordance with Section 10.6.2 ConnectionsThe performance of specimens is influ-enced by the type, spacing, and edge dista

28、nce of fastenersattaching sheathing to framing and spacing of the shearconnections and hold-down connectors to the rigid base. All ofthese connections shall be consistent with the types used inactual building connections.6.3 Frame RequirementsThe frame of the specimen shallconsist of materials repre

29、sentative of those to be used in theactual building construction. The connections of these mem-bers shall be consistent with those intended in actual buildingconstruction.6.3.1 For wood framing members, record the species andgrade of lumber used (or the relevant product identificationinformation for

30、 structural composite lumber framing); moisturecontent of the framing members at the time of the specimenfabrication and testing, if more than 24 h passes between theseoperations (see Test Methods D 4442, Method A or B; orD 4444, Method A or B); and specific gravity of the framingmembers (see Test M

31、ethods D 2395, Method A). The specificgravity of the framing members shall be representative of thepublished specific gravity for the product with no individualmember exceeding the published value by more that 10 %.6.3.2 For steel or other metal framing members, record thematerial specifications and

32、 thickness.6.4 Structural Insulated PanelThe panel is prefabricatedassembly consisting of an insulating core of 1.5 in. (38 mm)minimum sandwiched between two facings. The assembly isconstructed by attaching panels together and to top and bottomplates or tracks.6.5 Specimen SizeThe specimen shall hav

33、e a height andlength or aspect (height/length) ratio that is consistent withintended use requirements in actual building construction (seeFig. 3).7. Test Setup7.1 The specimen shall be tested such that all elements andsheathing surfaces are observable. For specimens such asframed walls with sheathin

34、g on both faces of framing orframeless structural insulated panels, the specimens are dis-mantled after tests to permit observation of all elements.7.2 The bottom of the specimen shall be attached to a testbase as specified in 6.2. The test apparatus shall support thespecimen as necessary to prevent

35、 displacement from the planeof the specimen, but in-plane displacement shall not berestricted.7.3 Racking load shall be applied horizontally along theplane of the specimen using a double-acting hydraulic actuatorFIG. 2 Performance Parameters of Specimen: (A) Last Point at Pu$ 0.8 PpeakE 2126 07a4wit

36、h a load cell. The load shall be distributed along the top ofthe specimen by means of a loading beam or other adequatedevices. The beam used to transfer loads between the hydrauliccylinder and the test specimen shall be selected so that it doesnot contribute to the measured racking strength and stif

37、fness.7.3.1 If applied to the top of the specimen directly, e.g., asis shown in Fig. 4, the maximum stiffness of load beampermitted is 330,000 lbf-in.2(see Note 2).NOTE 2The selected stiffness corresponds with an HSS 5 by 3 by14-in. steel section. Other sections with equal or less stiffness have bee

38、nsuccessfully employed.7.3.2 The load beam selected shall not be continuous overdiscontinuities in the test specimen (see Note 3).NOTE 3Examples of discontinuities include portal frame openings,wall perforations, transitions between differential bracing types, etc.Continuation of a rigid load beam o

39、ver these discontinuities can add to themeasured in-plane rigidity of the system. However, the use of continuousload beam over discontinuities may be considered provided that the addedin-plane rigidity can be justified by the end-use applications.7.3.3 The combined gravity load applied to the specim

40、en bythe load beam and actuator shall be less than 350 lbf, unless thepurpose of the test includes the influence of vertical loads onthe system performance (see Appendix X3).7.4 Test setup shall be designed and installed so that vertical(gravity) loads from test equipment applied to the specimen are

41、negligible. Other vertical loads shall not be added to thespecimen unless justified by analysis of actual building con-struction or the objective of the testing. When vertical loads areapplied, the magnitude and test setup for the vertical load shallbe reported along with the justification.NOTE 4The

42、 neglect of vertical loads in this standard may result ininaccurate estimates of the capacity of the specimen as an element of thelateral force resisting system in actual building construction. For example,the neglect of uplift forces in testing may overestimate the rackingcapacity of the element, w

43、hile the neglect of dead weight of the storyabove may underestimate the racking capacity of the element unlessbuckling is the predominant failure mode.8. Procedure8.1 Number of TestsA minimum of two identical speci-mens shall be tested to determine the elastic shear stiffness andshear strength of a

44、given construction. These values shall becalculated in accordance with 3.2 and 9.1. For analysis, themean values are permitted to be based on the results of twospecimens if the parameters are within 10 % of each other.Otherwise, the mean values shall be based on the results of atleast three specimen

45、s.8.2 The cyclic displacement of the actuator shall be con-trolled to follow a cyclic displacement procedure described ineither 8.3 (Method A), 8.4 (Method B), or 8.5 (Method C).8.3 Method A (Sequential-Phased Displacement Proce-dure):FIG. 2 Performance Parameters of Specimen: (B) Last Point at Pu=0

46、.8Ppeak(continued)E 2126 07a58.3.1 Sequential Phased Displacement (SPD) LoadingProtocolDisplacement-controlled loading procedure that in-volves displacement cycles grouped in phases at incrementallyincreasing displacement levels. The cycles shall form either asinusoidal wave or a triangular wave. Th

47、e SPD loadingconsists of two displacement patterns and is illustrated in Fig.FIG. 3 An Example of Shear Wall SpecimenFIG. 4 Cyclic Displacement Schedule (Method A)E 2126 07a64. The first displacement pattern consists of three phases, eachcontaining three fully-reversing cycles of equal amplitude, at

48、displacements representing 25 %, 50 %, and 75 % of antici-pated FME. The second displacement pattern is illustrated inFig. 5. Each phase is associated with a respective displacementlevel and contains one initial cycle, three decay cycles, and anumber of stabilization cycles. For nailed wood-frame wa

49、lls,three stabilization cycles are sufficient to obtain a stabilizedresponse. The amplitude of each consecutive decay cycledecreases by 25 % of the initial displacement.8.3.2 The schedule of amplitude increments between thesequential phases is given in Table 1. The amplitude incre-ments selected for the SPD procedure are based on the FMEdetermined from the static monotonic load test on an identicalspecimen in accordance with Practice E 564. To determineDyield, it is permitted to compute EEEP curves, as shown in Fig.2 based on monotonic test data,