ASTM D2719-89(1994)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: D 2719 – 89 (Reapproved 1994)
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—Section 11 was added editorially in January 1995.
1. Scope perimeter framing are desired, should the test method be
applied.
1.1 These test methods determine the shear through-the-
1.1.3 Test Method C: Two-Rail Shear Test—This test
thickness properties of structural panels associated with shear
method is applicable to a wide variety of materials and
distortion of the major axis. Structural panels in use include
problems. The specimen fabrication and test procedures are
plywood, wafer board, oriented strand board, and composites
somewhat simpler than in Test Methods A and B. The specimen
of veneer and of wood based layers. Three test methods are
is free to shear parallel to its 24-in.(610-mm) length dimension
included which differ somewhat in their application:
anywhere within the 8-in. (203-mm) width between rails. Thus,
Test Method Section
the test method is well suited for determining grade and
A. Small Panel Shear Test 5
B. Large Panel Shear Test 6
manufacturing effects such as core gaps and knots occupying
C. Two Rail Shear Test 7
and affecting small areas. The test method is not so ideally
The choice of test method will be determined in part by the suited for determination of modulus of rigidity, but when
purpose of the tests, characteristics of test material, and
adjusted for strain distribution effects, values approximating
equipment availability. In general, Test Method B or C for large those obtained by Test Method B result. The test simulates
specimens is preferred when equipment, amount of test mate-
effects of heavy framing when expected planes of weakness are
rial, and experimental plan permit. oriented perpendicular to rails and no framing at all when
1.1.1 Test Method A: Small Panel Shear Test—This test
parallel to rails.
method is suitable for testing small samples of uniform 1.2 Significant differences, moderate to small in magnitude,
material including investigations of the effects of grain direc-
among the three test methods have been found to exist when
tion or orientation and of many raw materials and manufactur- these test methods are applied to plywood of clear straight-
ing process variables which influence shear properties uni-
grained veneers. Therefore, when comparisons are made
formly throughout the specimen. The test method is unsuited among test results, it is recommended that the same test
for determining effects of grade and manufacturing features
method be used throughout.
such as density variations, knots, and core gaps within the 1.3 This standard does not purport to address all of the
specimen.
safety concerns, if any, associated with its use. It is the
1.1.2 Test Method B: Large Panel Shear Test—This test responsibility of the user of this standard to establish appro-
method is regarded as giving the most accurate modulus of
priate safety and health practices and determine the applica-
rigidity and is therefore recommended for elastic tests of
bility of regulatory limitations prior to use.
materials to be used in stress analysis studies of test structures.
2. Referenced Documents
This test also yields excellent shear strength values for clear
material. However, in spite of the large size of the specimen, 2.1 ASTM Standards:
failures generally occur only in narrow zones at the perimeter D 2395 Test Methods for Specific Gravity of Wood and
of the test area. This characteristic, a result of the heavy Wood-Base Materials
perimeter framing, causes this test method to be generally D 4442 Test Methods for Direct Moisture Content Measure-
unsuited for determining grade and manufacturing effects such ment of Wood and Wood–Base Materials
as density variations, core gaps, and knots that are not
3. Significance and Use
uniformly distributed throughout the panel. Generally, only in
cases where effects of these factors under conditions of heavy 3.1 The strength and modulus of rigidity of structural panels
in shear through-the-thickness obtained by these test methods
are required for the rigorous design of many lumber-panel
structural components such as trusses with panel gussets, box
These test methods are under the jurisdiction of ASTM Committee D-7 on
Wood 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, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 2719
beams, folded plate roofs, and space plane structures, as well as
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
on the opposite side of the veneer by forces at the compression
bar, and from checks caused by drying. Average depth of knife
Metric Equivalents
checks has been found to strongly influence shear properties in
1 1
in. ⁄16 ⁄2
plywood panels and may be of significance in veneer incorpo- mm 1.6 12.7
rated in composite panels. Measurement of depth of knife
FIG. 1 Small Panel Shear Specimen and Dimensions
checks is recommended in these test methods.
3.3 To control or define other variables influencing shear
shall be 90° and between each face and the base the angle shall
properties, these test methods require determination of mois-
be 45°. A spherical bearing block, preferably of the suspended,
ture content and elapsed time to failure. The conditioning of
self-aligning type, shall be employed in the loading system.
test material in controlled atmosphere and determination of
Apply the load continuously throughout the test with a uniform
specific gravity are recommended.
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 (mm/mm·min)
corresponding to a shear strain rate of 0.005 in./in.·min
4.1 Structural panel samples to be tested at a specific
(mm/mm·min) within a permissible variation of 625 %.
temperature/relative humidity shall be conditioned to approxi-
5.3.1 Load each of the eight reinforcing blocks through
mate constant weight in controlled atmospheric conditions
roller brackets clamped to the reinforcing block across its
before gluing wood rails. Conditioning of fabricated specimens
width or attached by other means and applying a compressive
at the same temperature and relative humidity shall be contin-
ued until the adhesive has cured sufficiently to ensure adequate force to the end of the reinforcing block through a surface
2 2
contact area of at least 0.75 in. (484 mm ). These bearing
bond strength. For approximating moisture conditions of struc-
surfaces shall be firmly seated against the ends of their
tural panels used under dry conditions, a relative humidity of
respective reinforcing blocks during assembly. Rollers shall be
65 6 2 % at a temperature of 68 6 6°F (20 6 3°C) is
centered at the inner edge of the reinforcing block and 1.25 in.
recommended.
(31.8 mm) from the loaded end of the reinforcing block.
5. Test Method A—Small Panel Shear Test
Moderate clamping pressure holding brackets to the reinforc-
5.1 Summary—A specimen having a square shear area ing blocks applied perpendicular to the plane of the panel is
bounded on each side by solid wood blocks glued to both sides permitted but shall not be excessive.
of the specimen is loaded in compression along one diagonal in 5.3.1.1 Fig. 2 illustrates detail of suitable roller brackets and
a conventional testing machine. Forces are applied to the their method of attachment to the reinforcing blocks with small
glued-on blocks through a roller bracket assembly which wood wedges. Fig. 3 shows a specimen loaded by means of
causes the resultant forces to act collinearly with the edge of roller brackets, and Fig. 4 gives working drawings for these
the shear test area. This loading method most nearly produces brackets. Brackets are clamped across the width of the rein-
uniform pure shear. Shear strength is determined from maxi- forcing blocks by driving small wedges between a projection
mum load, and modulus of rigidity may be calculated from on the bracket and the reinforcing block. The clamping bolt is
measurements of compression strain along the compression used to apply moderate clamping pressure perpendicular to the
diagonal of the specimen. plane of the specimen. Other bracket devices conforming to the
5.2 Test Specimen—Dimensions shown in Fig. 1 of the requirements of 5.3.1 are permitted but shall be described in
panel specimen and reinforcing blocks depend upon panel detail in the report of test results.
thickness. Distance between blocks, L, shall not exceed 20 5.3.1.2 Measure the elapsed time from initiation of loading
times specimen thickness, and block width and thickness shall to the maximum load and record to the nearest ⁄2 min.
not be less than 5 and 2.5 times specimen thickness, respec- 5.4 Measurement of Deformation—When deformation data
are desired for calculation of elastic properties, strain-
tively. Reinforcing blocks shall be of birch, maple, or other
wood of similar strength and rigidity. The average of specimen measuring devices having minimum gage length of 1 in. (25
thickness at two diagonally opposite corners and the dimen- mm) shall be attached to both sides of the specimen and shall
sions of the shear area inside the reinforcing blocks shall be measure compression strain of the vertical (or compression)
determined and recorded to the nearest 0.3 % or 0.001 in. diagonal, the gages being centered at its midpoint on each side.
(0.025 mm), whichever is larger. A larger gage length is preferred but shall not exceed one half
5.3 Loading—Apply the load by special steel loading the length of the diagonal. Instruments and the accuracy of
blocks which articulate with the rollers and pins attached to the their recording shall be to the nearest 0.0001 in. (0.0025 mm)
test specimen. The angle between faces of the loading block or 2 % of expected ultimate strain, whichever is smaller. Strain
D 2719
FIG. 2 Small Panel Shear Specimen with Roller Brackets
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.
6.2 Test Specimens—Fig. 5 gives detail of the specimen as
T 5 0.707 ~P/Lt! (1)
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 5 shear stress, psi (N/m ),
exceed 48 times total specimen thickness. When structural
P 5 load (force), lbf (N),
1 1
panels less than ⁄2 in. (12.7 mm) thick or less than ⁄48 the side
L 5 length of side of shear area, in. (m), (Fig. 1), and
of the shear area is to be tested for shear strength, two or more
t 5 thickness of shear specimen, in. (m).
thicknesses of structural panels may be glued together (major
5.5.2 Calculate modulus of rigidity from deformation data
axis parallel) to form a test panel of the required thickness.
as follows:
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
the test is halted due to initiation of buckling. Lumber rails
where:
having a length equal to the side of the shear area, thickness not
G 5 modulus of rigidity, psi (N/m ),
1 1
less than ⁄25 and width not less than ⁄6 the length of one side
P/D5 slope of force/deformation curve, lbf/in. (N/m),
of the shear area shall be glued to the structural panels with a
L 5 gage length, in. (m), and
rigid adhesive. Wider rails may be necessary to prevent rolling
t 5 thickness of shear specimen, in. (m).
shear failures between thick or high-strength panels and the
6. Test Method B—Large Panel Shear Test
rails. Corners of the structural panels specimen shall be
6.1 Summary—A specimen having a square shear area is notched with the inside corner of the notch provided with a
loaded through heavy lumber rails glued to both sides of the fillet of ⁄2-in. (12.7-mm) radius as shown in Fig. 5. Ends of the
specimen at all four edges of the shear area. Loading by a rails to which loads are applied shall form a flat plane
D 2719
FIG. 3 Small Panel Shear Specimen with Loading and Strain-Measuring Apparatus Placed in Testing Machine
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 is strained at the rate of 0.005 in./in. (mm/mm)/min
be measured to an accuracy of 0.01 in. (0.25 mm). shear strain6 25 %. Head speed may be calculated by the
6.3 Loading—Load the specimen loading jig assembly in
following equation:
tension. The resultant o
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