ASTM E2126-19

This document is not an 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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2126 − 11 (Reapproved 2018) E2126 − 19
Standard Test Methods for
Cyclic (Reversed) Load Test for Shear Resistance of Vertical
Elements of the Lateral Force Resisting Systems for
Buildings
This standard is issued under the fixed designation E2126; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 These test methods cover the evaluation of the shear stiffness, shear strength, and ductility of the vertical elements of lateral
force resisting systems, including applicable shear connections and hold-down connections, under quasi-static cyclic (reversed)
load conditions.
1.2 These test methods are intended for specimens constructed from wood or metal framing braced with solid sheathing or other
methods or structural insulated panels.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D2395 Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials
D4442 Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
D4444D7438 Test Method for Laboratory Standardization and CalibrationPractice for Field Calibration and Application of
Hand-Held Moisture Meters
E72 Test Methods of Conducting Strength Tests of Panels for Building Construction
E564 Practice for Static Load Test for Shear Resistance of Framed Walls for Buildings
E575 Practice for Reporting Data from Structural Tests of Building Constructions, Elements, Connections, and Assemblies
E631 Terminology of Building Constructions
2.2 ISO Standard:
ISO 16670 Timber Structures—Joints Made with Mechanical Fasteners—Quasi-static Reversed-cyclic Test Method
2.3 Other Standards:
4 4
ANSI/AF&PA NDSANSI/AWC NDS National Design Specification for Wood Construction
CSA O86 Engineering Design in Wood
These test methods are under the jurisdiction of ASTM Committee E06 on Performance of Buildings and are the direct responsibility of Subcommittee E06.11 on
Horizontal and Vertical Structures/Structural Performance of Completed Structures.
Current edition approved July 1, 2018Aug. 1, 2019. Published July 2018August 2019. Originally approved in 2001. Last previous edition approved in 20112018 as
E2126 – 11.E2126–11 (2018). DOI: 10.1520/E2126-11R18.10.1520/E2126–19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
Available from American Forest & Paper Association (AF&PA), 1101 K St., NW, Suite 700, Washington, DC 20005, http://www.afandpa.org.A registered trademark of
and available from American Wood Council, 222 Catoctin Circle SE, Suite 201, Leesburg, VA 20175, https://www.awc.org.
Available from CSA Group, 178 Rexdale Blvd. Toronto, ON Canada M9W 1R3, Canada, http://www.csagroup.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2126 − 19
3. Terminology
3.1 For definitions of terms used in this standard, see Terminology E631.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 ductility ratio, cyclic (D), n—the ratio of the ultimate displacement (Δ ) and the yield displacement (Δ ) of a specimen
u yield
observed in cyclic test.
3.2.2 elastic shear stiffness (K ) (see 9.1.4, Fig. 1),n—the resistance to deformation of a specimen in the elastic range before
e
the first major event (FME) is achieved, which can be expressed as a slope measured by the ratio of the resisted shear load to the
corresponding displacement.
3.2.3 envelope curve (see Fig. 2),n—the locus of extremities of the load-displacement hysteresis loops, which contains the peak
loads from the first cycle of each phase of the cyclic loading and neglects points on the hysteresis loops where the absolute value
of the displacement at the peak load is less than that in the previous phase.
3.2.3.1 Discussion—
Specimen displacement in the positive direction produces a positive envelope curve; the negative specimen displacement produces
a negative envelope curve. The positive direction is based on outward movement of the hydraulic actuator.
3.2.4 envelope curve, averageaverage (see Fig. 3),n—envelope curve obtained by averaging the absolute values of load and
displacement of the corresponding positive and the negative envelope points for each cycle.
3.2.4.1 Discussion—
For a monotonic test, the measured load-displacement curve is used as the average envelope curve for analysis purposes.
3.2.5 equivalent energy elastic-plastic (EEEP) curve (see 9.1.4, Fig. 1),n—an ideal elastic-plastic curve circumscribing an area
equal to the area enclosed by the envelope curve between the origin, the ultimate displacement, and the displacement axis. For
monotonic tests, the observed load-displacement curve is used to calculate the EEEP curve.
FIG. 1 Performance Parameters of Specimen: (A) Last Point at P $ 0.8 P
u peak
E2126 − 19
FIG. 1 Performance Parameters of Specimen: (B) Last Point at P = 0.8 P (continued)
u peak
FIG. 2 Examples of Observed Hysteresis Curve and Envelope Curves for Test Method A
E2126 − 19
FIG. 2 Examples of Observed Hysteresis Curve and Envelope Curves for Test Method B (continued)
3.2.6 failure limit state, n—the point on the envelope curve corresponding to the last data point with the absolute load equal or
greater than |0.8 P |, as illustrated in Fig. 1.
peak
3.2.7 failure load (P ), n—the load corresponding to the failure limit state.
u
3.2.8 first major event (FME), n—the first significant limit state to occur (see limit state).
3.2.9 limit state, n—an event that demarks the two behavior states, at which time some structural behavior of the specimen is
altered significantly.
3.2.10 specimen, n—the vertical element of the lateral force resisting system to be tested. Example of specimens are walls,
structural insulated panels, portal frames, etc. A specimen can be a single element or an entire line of resistance within a lateral
force resisting system.
3.2.11 stabilized response, n—load resistance that differs not more than 5 % between two successive cycles at the same
amplitude.
3.2.12 strength limit state (see Fig. 1),n—the point on the envelope curve corresponding to the maximum absolute displacement
Δ at the maximum absolute load (P ) resisted by the specimen.
peak peak
3.2.13 ultimate displacement, cyclic (Δ ), n—the displacement corresponding to the failure limit state in cyclic test.
u
3.2.14 ultimate displacement, monotonic (Δ ), n—the displacement corresponding to the failure limit state in monotonic test.
m
3.2.15 yield limit state, n—the point in the load-displacement relationship where the elastic shear stiffness of the assembly
decreases 5 % or more. For specimens with nonlinear ductile elastic response, the yield point (Δ , P ) is permitted to be
yield yield
determined using the EEEP curve (see 9.1.4).
4. Summary of Test Method
4.1 The elastic shear stiffness, shear strength and ductility of specimens are determined by subjecting a specimen to full-reversal
cyclic racking shear loads. This loads in accordance with one of the three cyclic test protocols. The test is accomplished by
anchoring the bottom edge of the specimen to a test base simulating intended end-use applications and applying a force parallel
to the top of the specimen. The specimen is allowed to displace in its plane. Sheathing panels that are a component of a specimen
shall be positioned such that they do not bear on the test frame during testing. (See Note 1.) As the specimen is racked to specified
E2126 − 19
FIG. 2 Examples of Observed Hysteresis Curve and Envelope Curves for Test Method C (continued)
FIG. 3 Example of Average Envelope Curve (see Fig. 2, Test Method C)
E2126 − 19
displacement increments, the racking (shear) load and displacements are continuously measured (see 8.78.8). A similarly
configured monotonic test also is provided as an available means to derive the cyclic test protocol.
NOTE 1—If the end-use applications require sheathing panels bear directly on the sill plate, such as most structural insulated panels, the specimen may
be tested with sheathing panels that bear on the sill plate.
5. Significance and Use
5.1 These cyclic test methods are intended to measure the performance of vertical elements of the lateral force resisting system
subjected to earthquake loads. Since these loads are cyclic, the loading process simulates the actions and their effects on the
specimens.
5.2 The monotonic test is intended to provide data from a continuous displacement ramp loading of a matched test specimen
with boundary conditions identical to the specimens that will be cyclically tested. The results from the monotonic test, when
employed, are primarily intended for defining the amplitudes of load cycles for the three cyclic protocols.
NOTE 2—The monotonic test is not intended to serve as an equivalent alternative to the cyclic protocols of this Test Method or the procedures of Test
Methods E72 or Practice E564.
6. Specimen
6.1 General—The typical specimen consists of a frame, bracing elements, such as panel sheathing, diagonal bracing, etc., and
fastenings. The bracing is attached on one side of the frame unless the purpose of the test requires bracing on both sides. The
elements of the specimen shall be fastened to the frame in a manner to conform to 6.2. Elements used to construct specimens may
be varied to permit anticipated failure of selected elements. All detailing shall be clearly identified in the report in accordance with
Section 10.
6.2 Connections—The performance of specimens is influenced by the type, spacing, and edge distance of fasteners attaching
sheathing to framing and spacing of the shear connections and hold-down connectors, if applicable, and the tightness of the
fasteners holding the specimen to the test base.
6.2.1 Sheathing Panel Attachments—All panel attachments shall be consistent with the types used in actual building
construction. Structural details, such as fastener schedules, fastener edge distance, and the gap between panels, shall be reported
in accordance with Section 10.
6.2.2 Attachment to the Test Base—Specimen shall be attached to the test base with fasteners in a manner representing field
conditions. For intended use requirements over a non-rigid foundation, a mock-up flexible base shall be constructed to simulate
field conditions. Consideration shall be given to the orientation and type of floor joists relative to the orientation of the wall
assembly. When strap connections are used, they shall be installed (that is, inside/outside the sheathing, etc.) without pre-tension
in a configuration that simulates the field application. The test report shall include details regarding this attachment.
6.2.3 Anchor and Hold-Down Bolts—When the specimen frame is made of solid wood or wood-based composites, the anchor
bolts shall be tightened to no more than finger tight plus a ⁄8 turn, provided that the design value of stress perpendicular to the
grain is not exceeded (see exceeded. Note 2). The hold-down bolts shall be tightened consistently between replicates in accordance
with hold-down manufacturer’s recommendation. The assembly test shall not start within 10 min of the anchor bolt tightening to
allow for stress relaxation of the anchor.
NOTE 3—Since solid wood and wood-based composites relax over time as well as potentially shrink due to changing moisture content, the intent of
the finger tight plus a ⁄8 turn is to avoid any significant pre-tension on the anchor bolts, which may affect the test results. It is the committee judgment
that the maximum bolt tension should not be more than 300 lbf (1.33 kN) for the purpose of ensuring the bolt is not caught on a thread or not seated
fully. It should be noted that, however, the bolt tension depends on wood species and density, bolt thread pitch (or bolt diameter), and plate washer size.
1 1
A general rule of thumb is to finger-tight plus ⁄8 turn, which will result in a nut displacement of approximately 0.01 in. (0.254 mm) for ⁄2 and
⁄8-in.-diameter in. diameter (12.7 and 15.9-mm-diameter) 15.9 mm diameter) UNC bolts. A torque of about 50 lbf-in. (5.65 kN-mm) without bolt
lubrication would normally produce 300 lbf (1.33 kN) of bolt tension.
6.3 Frame Requirements—The frame of the specimen shall consist of materials representative of those to be used in the actual
building construction. The connections of these members shall be consistent with those intended in actual building construction.
6.3.1 For wood framing members, record the species and grade of lumber used (oror the relevant product identification
information for structural composite lumber framing);framing; moisture content of the framing members at the time of the
specimen fabrication and testing, if more than 24 h passes between these operations (see(use Test Methods D4442, Test Methods
A or B; or D4444,Practice D7438Test Methods A or B); ); and specific gravity of the critical framing members (see(use Test
Methods D2395, Test Method A). The Methods A or B). The measured average oven-dry specific gravity of the critical framing
members shall be representative of the reference published specific gravity for the product with no individual member exceeding
the published value by more that 10 % (see ANSI/AF&PA NDS for example).as outlined below:
6.3.1.1 Light-frame Wood Stud Shearwalls with Structural Panel Sheathing—The critical members to be measured shall be
those that receive perimeter sheathing fasteners at the sheathing panel boundaries. The measured average oven-dry specific gravity
of these members shall not exceed the published reference specific gravity by more than 0.03.
E2126 − 19
6.3.1.2 All Other Systems with Wood Framing—The critical wood framing members to be measured shall be those that directly
contribute to the in-plane shear strength and stiffness of the specimen. No individual framing member shall exceed the published
reference specific gravity by more than 10 %.
NOTE 4—Test Methods D2395, Method G, is sometimes useful for an approximate specific gravity determination that can be used to pre-sort materials
prior to constructing a specimen. While it does not provide a direct correlation to Test Methods D2395, Methods A or B, for any given piece, it can help
to predict the average oven-dry specific gravity of the framing prior to building the specimen. Published reference values for specific gravity can be found
in documents such as the ANSI/AWC NDS and CSA O86.
6.3.2 For steel or other metal framing members, record the material specifications and thickness.
6.4 Structural Insulated Panel—The panel is prefabricated assembly consisting of an insulating core of 1.5 in. (38 mm)
minimum sandwiched between two facings. The assembly is constructed by attaching panels together and to top and bottom plates
or tracks.
6.5 Specimen Size—The specimen shall have a height and length or aspect (height/length) ratio that is consistent with intended
use requirements in actual building construction (see Fig. 4).
7. Test Setup
7.1 The specimen shall be tested such that all elements and sheathing surfaces are observable. For specimens such as framed
walls with sheathing on both faces of framing or frameless structural insulated panels, the specimens are dismantled after tests to
permit observation of all elements.
7.2 The bottom of the specimen shall be attached to a test base as specified in 6.2. The test apparatus shall support the specimen
as necessary to prevent displacement from the plane of the specimen, but in-plane displacement shall not be restricted.
7.3 Racking load shall be applied horizontally along the plane of the specimen using a double-acting hydraulic actuator with
a load cell. The load shall be distributed along the top of the specimen by means of a loading beam or other adequate devices. The
beam used to transfer loads between the hydraulic cylinder and the test specimen shall be selected so that it does not contribute
to the measured racking strength and stiffness.
7.3.1 If applied to the top of the specimen directly, for example, as is shown in Fig. 5, the maximum stiffness of load beam
2 2
permitted is 330 000 kips-in. (947 kN-m ) (see Note 3).
FIG. 4 An Example of Shear Wall Specimen
E2126 − 19
FIG. 5 An Example of Test Setup for Shear Wall Specimen
NOTE 5—The selected stiffness corresponds with an HSS 5 ×by 3 ×by ⁄4-in. in. (127 × 76 × 6.4-mm) by 76 by 6.4 mm) steel section. Other sections
with equal or less stiffness have been successfully employed.
7.3.2 The load beam selected shall not be continuous over discontinuities in the test specimen (see specimen.Note 4).
NOTE 6—Examples of discontinuities include portal frame openings, wall perforations, transitions between differential bracing types, etc. Continuation
of a rigid load beam over these discontinuities can add to the measured in-plane rigidity of the system. However, the use of continuous load beam over
discontinuities may be considered provided that the added in-plane rigidity can be justified by the end-use applications.
7.3.3 The combined gravity load applied to the specimen by the load beam and actuator shall be less than 350 lbf (1.56 kN),
unless the purpose of the test includes the influence of vertical loads on the 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
negligible. Other vertical loads shall not be added to the specimen unless justified by analysis of actual building construction or
the objective of the testing. When vertical loads are applied, the magnitude and test setup for the vertical load shall be reported
along with the justification.
NOTE 7—The neglect of vertical loads in this standard may result in inaccurate estimates of the capacity of the specimen as an element of the lateral
force resisting system in actual building construction. For example, the neglect of uplift forces in testing may overestimate the racking capacity of the
element, while the neglect of dead weight of the story above may underestimate the racking capacity of the element unless buckling is the predominant
failure mode.
8. Procedure
8.1 Number of Tests—A minimum of two specimens of a given construction shall be tested cyclically if the shear strength (v )
peak
values of each specimen calculated according to 9.1.1 are within 10 % of each other. The lower of the two test values shall be used
to calculate the 10 % allowance. Otherwise, at least three specimens of a given construction shall be tested.cyclically tested. When
required to initially define the cyclic test displacement cycle amplitudes, at least one monotonic test shall be conducted.
E2126 − 19
8.2 The cyclic displacement of the actuator shall be controlled to follow a cyclic displacement procedureschedule described in
either 8.3 (Test Method A), 8.4 (Test Method B), or 8.5 (Test Method C). Monotonic displacement of the actuator shall be
controlled to follow the continuous ramp described in 8.6 (Test Method D).
8.3 Test Method A (Sequential-Phased Displacement Procedure):
8.3.1 Sequential Phased Displacement (SPD) Loading Protocol—Displacement-controlled loading procedure that involves
displacement cycles grouped in phases at incrementally increasing displacement levels. The cycles shall form either a sinusoidal
wave or a triangular wave. The SPD loading consists of two displacement patterns and is illustrated in Fig. 6. The first displacement
pattern consists of three phases, each containing three fully-reversing cycles of equal amplitude, at displacements representing
25 %, 50 %, and 75 % of anticipated FME. The second displacement pattern is illustrated in Fig. 7. Each phase is associated with
a respective displacement level and contains one initial cycle, three decay cycles, and a number of stabilization cycles. For nailed
wood-frame walls, three stabilization cycles are sufficient to obtain a stabilized response. The amplitude of each consecutive decay
cycle decreases by 25 % of the initial displacement.
8.3.2 The schedule of amplitude increments between the sequential phases is given in Table 1. The amplitude increments
selected for the SPD procedure are based on the FME determined from the static monotonic load test on an identical specimen in
accordance with PracticeTest E564. Method D. To determine Δ , it is permitted to compute EEEP curves, as shown in Fig. 1
yield
based on monotonic test data, in accordance with 9.1.4.
8.4 Test Method B (ISO 16670 Protocol):
8.4.1 ISO Displacement Schedule—Displacement-controlled loading procedure that involves displacement cycles grouped in
phases at incrementally increasing displacement levels. The ISO loading schedule consists of two displacement patterns and is
illustrated in Fig. 8. The first displacement pattern consists of five single fully reversed cycles at displacements of 1.25 %, 2.5 %,
5 %, 7.5 %, and 10 % of the ultimate displacement Δ . The second displacement pattern consists of phases, each containing three
m
fully reversed cycles of equal amplitude, at displacements of 20 %, 40 %, 60 %, 80 %, 100 %, and 120 % of the ultimate
displacement Δ .
m
8.4.2 The sequence of amplitudes, which is given in Table 2, are a function of the mean value (where applicable) of the ultimate
displacement (Δ ) obtained from matched specimens in the monotonic tests on a matched specimen in accordance with
m
PracticeTest E564.Method D.
8.5 Test Method C (CUREE Basic Loading Protocol):
8.5.1 CUREE Basic Loading Protocol—Displacement-controlled loading procedure that involves displacement cycles grouped
in phases at incrementally increasing displacement levels. The loading history starts with a series of (six) initiation cycles at small
amplitudes (of equal amplitude). Further, each phase of the loading history consists of a primary cycle with amplitude expressed
as a fraction (percent) of the reference deformation, Δ, and subsequent trailing cycles with amplitude of 75 % of the primary one.
NOTE 8—The initiation cycles serve to check loading equipment, measurement devices, and the force-deformation response at small amplitudes.
FIG. 6 Cyclic Displacement Schedule (Test Method A)
E2126 − 19
FIG. 7 Single Phase of Pattern 2 (Test Method A)
FIG. 8 Cyclic Displacement Schedule (Test Method B)
8.5.2 The schedule of amplitude increments is given in Table 3 and is illustrated in Fig. 9. The reference deformation Δ shall
be an estimate of the maximum displacement at which the load in a primary cycle has not yet dropped below 0.8 P . The value
peak
of Δ shall not exceed 0.025 times the wall height. In the absence of previous data or a consensus value, an initial estimate of the
maximum displacement shall be permitted to be obtained from a monotonic test on
...