ASTM D2719-89(2001)e1
(Test Method)Standard Test Methods for Structural Panels in Shear Through-the-Thickness
Standard Test Methods for Structural Panels in Shear Through-the-Thickness
SCOPE
1.1 These test methods determine the shear through-the-thickness properties of structural panels associated with shear distortion of the major axis. Structural panels in use include plywood, wafer board, oriented strand board, and composites of veneer and of wood based layers. Three test methods are included which differ somewhat in their application: Test MethodSectionA.Small Panel Shear Test5B.Large Panel Shear Test6C.Two Rail Shear Test7
The choice of test method will be determined in part by the purpose of the tests, characteristics of test material, and equipment availability. In general, Test Method B or C for large specimens is preferred when equipment, amount of test material, and experimental plan permit.
1.1.1 Test Method A: Small Panel Shear Test—This test method is suitable for testing small samples of uniform material including investigations of the effects of grain direction or orientation and of many raw materials and manufacturing process variables which influence shear properties uniformly throughout the specimen. The test method is unsuited for determining effects of grade and manufacturing features such as density variations, knots, and core gaps within the specimen.
1.1.2 Test Method B: Large Panel Shear Test—This test method is regarded as giving the most accurate modulus of rigidity and is therefore recommended for elastic tests of materials to be used in stress analysis studies of test structures. This test method also yields excellent shear strength values for clear material. However, in spite of the large size of the specimen, failures generally occur only in narrow zones at the perimeter of the test area. This characteristic, a result of the heavy perimeter framing, causes this test method to be generally unsuited for determining grade and manufacturing effects such as density variations, core gaps, and knots that are not uniformly distributed throughout the panel. Generally, only in cases where effects of these factors under conditions of heavy perimeter framing are desired, should the test method be applied.
1.1.3 Test Method C: Two-Rail Shear Test— This test method is applicable to a wide variety of materials and problems. The specimen fabrication and test procedures are somewhat simpler than in Test Methods A and B. The specimen is free to shear parallel to its 24-in.(610-mm) length dimension anywhere within the 8-in. (203-mm) width between rails. Thus, the test method is well suited for determining grade and manufacturing effects such as core gaps and knots occupying and affecting small areas. The test method is not so ideally suited for determination of modulus of rigidity, but when adjusted for strain distribution effects, values approximating those obtained by Test Method B result. The test method simulates effects of heavy framing when expected planes of weakness are oriented perpendicular to rails and no framing at all when parallel to rails.
1.2 Significant differences, moderate to small in magnitude, among the three test methods have been found to exist when these test methods are applied to plywood of clear straight-grained veneers. Therefore, when comparisons are made among test results, it is recommended that the same test method be used throughout.
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.
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e1
Designation:D2719–89(Reapproved 2001)
Standard Test Methods for
Structural Panels in Shear Through-the-Thickness
This standard is issued under the fixed designation D 2719; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Metric conversions were added in 5.3 in May 2002.
1. Scope cases where effects of these factors under conditions of heavy
perimeter framing are desired, should the test method be
1.1 These test methods determine the shear through-the-
applied.
thickness properties of structural panels associated with shear
1.1.3 Test Method C: Two-Rail Shear Test—This test
distortion of the major axis. Structural panels in use include
method is applicable to a wide variety of materials and
plywood, wafer board, oriented strand board, and composites
problems. The specimen fabrication and test procedures are
of veneer and of wood based layers. Three test methods are
somewhatsimplerthaninTestMethodsAandB.Thespecimen
included which differ somewhat in their application:
is free to shear parallel to its 24-in.(610-mm) length dimension
Test Method Section
anywherewithinthe8-in.(203-mm)widthbetweenrails.Thus,
A. Small Panel Shear Test 5
B. Large Panel Shear Test 6
the test method is well suited for determining grade and
C. Two Rail Shear Test 7
manufacturing effects such as core gaps and knots occupying
The choice of test method will be determined in part by the and affecting small areas. The test method is not so ideally
purpose of the tests, characteristics of test material, and
suited for determination of modulus of rigidity, but when
equipmentavailability.Ingeneral,TestMethodBorCforlarge adjusted for strain distribution effects, values approximating
specimens is preferred when equipment, amount of test mate-
those obtained by Test Method B result. The test method
rial, and experimental plan permit. simulates effects of heavy framing when expected planes of
1.1.1 Test Method A: Small Panel Shear Test—This test
weakness are oriented perpendicular to rails and no framing at
method is suitable for testing small samples of uniform all when parallel to rails.
material including investigations of the effects of grain direc-
1.2 Significant differences, moderate to small in magnitude,
tion or orientation and of many raw materials and manufactur-
among the three test methods have been found to exist when
ing process variables which influence shear properties uni- these test methods are applied to plywood of clear straight-
formly throughout the specimen. The test method is unsuited
grained veneers. Therefore, when comparisons are made
for determining effects of grade and manufacturing features among test results, it is recommended that the same test
such as density variations, knots, and core gaps within the
method be used throughout.
specimen. 1.3 This standard does not purport to address all of the
1.1.2 Test Method B: Large Panel Shear Test—This test
safety concerns, if any, associated with its use. It is the
method is regarded as giving the most accurate modulus of responsibility of the user of this standard to establish appro-
rigidity and is therefore recommended for elastic tests of
priate safety and health practices and determine the applica-
materials to be used in stress analysis studies of test structures. bility of regulatory limitations prior to use.
This test method also yields excellent shear strength values for
2. Referenced Documents
clear material. However, in spite of the large size of the
specimen, failures generally occur only in narrow zones at the 2.1 ASTM Standards:
perimeter of the test area. This characteristic, a result of the D 2395 Test Methods for Specific Gravity of Wood and
heavy perimeter framing, causes this test method to be gener- Wood-Base Materials
ally unsuited for determining grade and manufacturing effects D 4442 TestMethodsforDirectMoistureContentMeasure-
such as density variations, core gaps, and knots that are not ment of Wood and Wood–Base Materials
uniformly distributed throughout the panel. Generally, only in
3. Significance and Use
3.1 The strength and modulus of rigidity of structural panels
in shear through-the-thickness obtained by these test methods
ThesetestmethodsareunderthejurisdictionofASTMCommitteeD7onWood
and are the direct responsibility of Subcommittee D07.03 on Panel Products.
Current edition approved Aug. 25, 1989. Published October 1989. Originally
1 2
published as D 2719 – 69 T. Last previous edition D 2719 – 76 (1981)e . Annual Book of ASTM Standards, Vol 04.10.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2719
are required for the rigorous design of many lumber-panel
structural components such as trusses with panel gussets, box
beams,foldedplateroofs,andspaceplanestructures,aswellas
floor and roof diaphragms, and shear walls. These properties
are of secondary importance in typical roof deck and sheathing
applications, and in crates and shipping containers.
3.2 Veneer produced by slicing or rotary peeling may
contain fine checks or separations parallel to the grain on the
knife side of the veneer that are produced as the knife is forced
through the wood. These checks are termed “knife checks” to
distinguish them from occasional checks that may be formed
Metric Equivalents
on the opposite side of the veneer by forces at the compression
1 1
in. ⁄16 ⁄2
mm 1.6 12.7
bar, and from checks caused by drying.Average depth of knife
checks has been found to strongly influence shear properties in
FIG. 1 Small Panel Shear Specimen and Dimensions
plywood panels and may be of significance in veneer incorpo-
rated in composite panels. Measurement of depth of knife
5.3 Loading—Apply the load by special steel loading
checks is recommended in these test methods.
blocks which articulate with the rollers and pins attached to the
3.3 To control or define other variables influencing shear
test specimen. The angle between faces of the loading block
properties, these test methods require determination of mois-
shall be 90° and between each face and the base the angle shall
ture content and elapsed time to failure. The conditioning of
be 45°.Aspherical bearing block, preferably of the suspended,
test material in controlled atmosphere and determination of
self-aligning type, shall be employed in the loading system.
specific gravity are recommended.
Apply the load continuously throughout the test with a uniform
motion of the movable head of the testing machine equal to
4. Control of Moisture Content
0.0025 in./in. of test area diagonal length/min (0.0025 mm/
4.1 Structural panel samples to be tested at a specific
mm/min) corresponding to a shear strain rate of 0.005 in./in./
temperature/relative humidity shall be conditioned to approxi-
min (0.005 mm/mm/min) within a permissible variation of
mate constant weight in controlled atmospheric conditions
625 %.
beforegluingwoodrails.Conditioningoffabricatedspecimens
5.3.1 Load each of the eight reinforcing blocks through
at the same temperature and relative humidity shall be contin-
roller brackets clamped to the reinforcing block across its
ued until the adhesive has cured sufficiently to ensure adequate
width or attached by other means and applying a compressive
bond strength. For approximating moisture conditions of struc-
force to the end of the reinforcing block through a surface
tural panels used under dry conditions, a relative humidity of
2 2
contact area of at least 0.75 in. (484 mm ). These bearing
65 6 2 % at a temperature of 68 6 6°F (20 6 3°C) is
surfaces shall be firmly seated against the ends of their
recommended.
respective reinforcing blocks during assembly. Rollers shall be
centered at the inner edge of the reinforcing block and 1.25 in.
5. Test Method A—Small Panel Shear Test
(31.8 mm) from the loaded end of the reinforcing block.
5.1 Summary—A specimen having a square shear area Moderate clamping pressure holding brackets to the reinforc-
bounded on each side by solid wood blocks glued to both sides
ing blocks applied perpendicular to the plane of the panel is
ofthespecimenisloadedincompressionalongonediagonalin
permitted but shall not be excessive.
a conventional testing machine. Forces are applied to the
5.3.1.1 Fig. 2 illustrates detail of suitable roller brackets and
glued-on blocks through a roller bracket assembly which
their method of attachment to the reinforcing blocks with small
causes the resultant forces to act collinearly with the edge of
wood wedges. Fig. 3 shows a specimen loaded by means of
the shear test area. This loading method most nearly produces
roller brackets, and Fig. 4 gives working drawings for these
uniform pure shear. Shear strength is determined from maxi- brackets. Brackets are clamped across the width of the rein-
mum load, and modulus of rigidity may be calculated from
forcing blocks by driving small wedges between a projection
measurements of compression strain along the compression on the bracket and the reinforcing block. The clamping bolt is
diagonal of the specimen.
used to apply moderate clamping pressure perpendicular to the
5.2 Test Specimen—Dimensions shown in Fig. 1 of the planeofthespecimen.Otherbracketdevicesconformingtothe
panel specimen and reinforcing blocks depend upon panel requirements of 5.3.1 are permitted but shall be described in
thickness. Distance between blocks, L, shall not exceed 20 detail in the report of test results.
times specimen thickness, and block width and thickness shall 5.3.1.2 Measure the elapsed time from initiation of loading
not be less than 5 and 2.5 times specimen thickness, respec- to the maximum load and record to the nearest ⁄2 min.
tively. Reinforcing blocks shall be of birch, maple, or other 5.4 Measurement of Deformation—When deformation data
wood of similar strength and rigidity. The average of specimen are desired for calculation of elastic properties, strain-
thickness at two diagonally opposite corners and the dimen- measuring devices having minimum gage length of 1 in. (25
sions of the shear area inside the reinforcing blocks shall be mm) shall be attached to both sides of the specimen and shall
determined and recorded to the nearest 0.3 % or 0.001 in. measure compression strain of the vertical (or compression)
(0.025 mm), whichever is larger. diagonal, the gages being centered at its midpoint on each side.
D2719
FIG. 2 Small Panel Shear Specimen with Roller Brackets
A larger gage length is preferred but shall not exceed one half 6. Test Method B—Large Panel Shear Test
the length of the diagonal. Instruments and the accuracy of
6.1 Summary—A specimen having a square shear area is
their recording shall be to the nearest 0.0001 in. (0.0025 mm)
loaded through heavy lumber rails glued to both sides of the
or 2 % of expected ultimate strain, whichever is smaller. Strain
specimen at all four edges of the shear area. Loading by a
readings of the two gages shall be averaged for computation of
system of pins and yokes applies forces to the rails having a
elastic properties.
resultant acting at the inside edge of the shear area. Maximum
5.5 Calculation:
shear strength is determined from maximum load and modulus
5.5.1 Calculate the maximum shear stress or shear stress at
of rigidity from elongation of the tension diagonal and corre-
the proportional limit as follows:
sponding loads.
T 5 0.707 ~P/Lt! (1)
6.2 Test Specimens—Fig. 5 gives detail of the specimen as
well as a suitable loading method. Shear area of the specimen
where:
shall not be less than 24 in. (610 mm) on a side, and shall not
T = shear stress, psi (N/m ),
exceed 48 times total specimen thickness. When structural
P = load (force), lbf (N),
1 1
L = length of side of shear area, in. (m), (Fig. 1), and panels less than ⁄2 in. (12.7 mm) thick or less than ⁄48 the side
t = thickness of shear specimen, in. (m).
of the shear area is to be tested for shear strength, two or more
5.5.2 Calculate modulus of rigidity from deformation data thicknesses of structural panels may be glued together (major
as follows:
axis parallel) to form a test panel of the required thickness.
Specimens to be tested for modulus of rigidity only may be of
G 5 0.3536 ~P/D!@L /~L · t! (2)
lesser thickness provided sufficient data can be obtained before
where:
the test is halted due to initiation of buckling. Lumber rails
G = modulus of rigidity, psi (N/m ),
havingalengthequaltothesideofthesheararea,thicknessnot
P/D = slope of force/deformation curve, lbf/in. (N/m), 1 1
less than ⁄25 and width not less than ⁄6 the length of one side
L = gage length, in. (m), and
of the shear area shall be glued to the structural panels with a
t = thickness of shear specimen, in. (m).
rigid adhesive. Wider rails may be necessary to prevent rolling
D2719
FIG. 3 Small Panel Shear Specimen with Loading and Strain-Measuring Apparatus Placed in Testing Machine
shear failures between thick or high-strength panels and the 6.3.1 Suitable loading equipment is illustrated in Fig. 5 and
rails. Corners of the structural panels specimen shall be Fig. 7. Major compression forces are applied by yokes to the
notched with the inside corner of the notch provided with a endsoftherailsataslightangletotherailaxisthroughbearing
fillet of ⁄2-in. (12.7-mm) radius as shown in Fig. 5. Ends of the plates.At its other end, a pin having a notched end centers the
rails to which loads are applied shall form a flat plane pin and yoke over the inside edge of the rail. Forces acting at,
perpendicular to the plane of the specimen. Use of a jig to and parallel to, the inner edge of the rail are applied to these
position rails accurately at the time of assembly or a light saw pins by short links. At its other end, the link connects to a pin
cut across the end of both rails after assembly may be helpful. centered at the corner of the shear area to which the link
Depending upon the method of deformation measurement, loading the adjacent rail is also connected. This pin is loaded
holes for gage pins may be needed as illustrated in Fig. 5. through a third link connecting to the test machine crosshead.
Average specimen thickness shall be determined from mea-
6.3.2 Load the specimen by constant motion of the movable
surements at each corner of the shear area to an accuracy of crosshead throughout the test such that the shear area of the
0.001 in. (0.025 mm). Width and length of the shear area shall
specimen
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