ASTM D4761-02

Standard Test Methods for Mechanical Properties of Lumber and Wood-Base Structural Material

SCOPE
Note 1—A proof load may be used which will permit the determination of a specified strength percentile without testing the total sample to destruction. Designing a test program on the basis of proof loading can be complex, requiring consideration in relation to the objectives of the test program. Guidance on this matter can be found in the paper by Johnson.
1.1 These test methods cover the determination of the mechanical properties of stress-graded lumber and other wood-base structural material.
1.2 These test methods appear in the following order: SectionBending edge-wise6-11Bending flat-wise:Center point loading12-17Third point loading18-23 Axial strength in tension24-29Axial strength in compression 30-35
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.

General Information

• Status: Historical
• Publication Date: 09-Apr-2002
• ICS: 79.040 - Wood, sawlogs and sawn timber
• ICS: 79.060.01 - Wood-based panels in general
• Technical Committee: D07 - Wood
• Drafting Committee: D07.01 - Fundamental Test Methods and Properties

Relations

• Replaced By: ASTM D4761-02a - Standard Test Methods for Mechanical Properties of Lumber and Wood-Base Structural Material
• Effective Date: 10-Nov-2002
• Referred By: ASTM D7672-19 - Standard Specification for Evaluating Structural Capacities of Rim Board Products and Assemblies
• Effective Date: 10-Apr-2002
• Referred By: ASTM D3043-17 - Standard Test Methods for Structural Panels in Flexure
• Effective Date: 10-Apr-2002
• Referred By: ASTM D143-22 - Standard Test Methods for Small Clear Specimens of Timber
• Effective Date: 10-Apr-2002
• Referred By: ASTM D7341-21 - Standard Practice for Establishing Characteristic Values for Flexural Properties of Structural Glued Laminated Timber by Full-Scale Testing
• Effective Date: 10-Apr-2002
• Referred By: ASTM D7032-21 - Standard Specification for Establishing Performance Ratings for Wood-Plastic Composite and Plastic Lumber Deck Boards, Stair Treads, Guards, and Handrails
• Effective Date: 10-Apr-2002
• Referred By: ASTM D7031-11(2019) - Standard Guide for Evaluating Mechanical and Physical Properties of Wood-Plastic Composite Products
• Effective Date: 10-Apr-2002
• Referred By: ASTM D8391-22e1 - Standard Specification for Demonstrating Equivalent Fire Performance for Wood-Based Floor Framing Members to Unprotected 2 by 10 Dimension Lumber or Equal-Sized Structural Composite Lumber
• Effective Date: 10-Apr-2002
• Referred By: ASTM D7381-07(2021)e1 - Standard Practice for Establishing Allowable Stresses for Round Timbers for Piles from Tests of Full-Size Material
• Effective Date: 10-Apr-2002
• Referred By: ASTM D198-22a - Standard Test Methods of Static Tests of Lumber in Structural Sizes
• Effective Date: 10-Apr-2002
• Referred By: ASTM D7199-20 - Standard Practice for Establishing Characteristic Values for Reinforced Glued Laminated Timber (Glulam) Beams Using Mechanics-Based Models
• Effective Date: 10-Apr-2002
• Referred By: ASTM D5055-19e1 - Standard Specification for Establishing and Monitoring Structural Capacities of Prefabricated Wood I-Joists
• Effective Date: 10-Apr-2002
• Referred By: ASTM D6815-22a - Standard Specification for Evaluation of Duration of Load and Creep Effects of Wood and Wood-Based Products
• Effective Date: 10-Apr-2002
• Referred By: ASTM D6874-22a - Standard Test Methods for Nondestructive Evaluation of the Stiffness of Wood and Wood-Based Materials Using Transverse Vibration or Stress Wave Propagation
• Effective Date: 10-Apr-2002
• Referred By: ASTM D3737-18e1 - Standard Practice for Establishing Allowable Properties for Structural Glued Laminated Timber (Glulam)
• Effective Date: 10-Apr-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 4761 – 02
Standard Test Methods for
Mechanical Properties of Lumber and Wood-Base Structural
Material
This standard is issued under the fixed designation D 4761; 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.
INTRODUCTION
Numerous evaluations of the mechanical properties of wood-based structural material have been
satisfactorily conducted since the late 1920s, using Methods D 198. Those methods are best suited to
a laboratory environment and are adaptable to a variety of products such as stress-graded lumber, sawn
timber, laminated timbers, wood-plywood composite members, reinforced and prestressed timbers.
The procedures presented in these test methods have been derived from those set forth in Methods
D 198. They are intended primarily for application to stress-graded lumber, but can be used for other
wood-base structural material as well. The procedures are more flexible than those in Methods D 198,
making testing in a nonlaboratory environment more feasible. Thus the test methods can be used on
production sites for field testing and quality control, as well as in laboratories for research applications.
Key differences from Methods D 198 are the testing speed, the deflection measuring procedures for
test specimens under load, and the detail of data reporting. Furthermore, the test methods do not
require that specimens be loaded to failure (Note 1).
Since these test methods allow latitude in testing procedures, the procedures used shall be fully
documented in the test report. It may also be desirable to correlate the results from tests carried out
according to these test methods with test results obtained through the use of a traditional procedure
such as set forth in Methods D 198.
1. Scope safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
NOTE 1—A proof load may be used which will permit the determination
priate safety and health practices and determine the applica-
of a specified strength percentile without testing the total sample to
bility of regulatory limitations prior to use.
destruction. Designing a test program on the basis of proof loading can be
complex, requiring consideration in relation to the objectives of the test
2. Referenced Documents
program. Guidance on this matter can be found in the paper by Johnson.
2.1 ASTM Standards:
1.1 These test methods cover the determination of the
D 9 Terminology Relating to Wood
mechanical properties of stress-graded lumber and other wood-
D 198 Methods of Static Tests of Timber in Structural
base structural material.
Sizes
1.2 These test methods appear in the following order:
D 2915 Practice for Evaluating Allowable Properties for
Section
Bending edge-wise 6-11 Grades of Structural Lumber
Bending flat-wise:
D 4442 Test Methods for Direct Moisture Content Measure-
Center point loading 12-17
ment of Wood and Wood-Base Materials
Third point loading 18-23
Axial strength in tension 24-29 E 4 Practices for Force Verification of Testing Machines
Axial strength in compression 30-35
E 6 Terminology Relating to Methods of Mechanical Test-
ing
1.3 This standard does not purport to address all of the
E 177 Practice for Use of the Terms Precision and Bias in
ASTM Test Methods
2.2 Other Document:
These test methods are under the jurisdiction of ASTM Committee D07 on
Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental
Test Methods & Properties.
Current edition approved April 10, 2002. Published June 2002. Originally
published as D 4761 – 88. Last previous edition D 4761 – 96. Annual Book of ASTM Standards, Vol 04.10.
2 4
“Current Statistical Methods for Estimating Lumber Properties by Proof Annual Book of ASTM Standards, Vol 03.01.
Loading,” Johnson, R. A., Forest Products Journal, Vol 30, No. 1, 1980, pp. 14–22. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4761
NIST Voluntary Product Standard PS20-70 American Soft- 7. Summary of Test Method
wood Lumber Standard
7.1 The test specimen is simply supported and loaded by
two concentrated forces spaced equidistant from the supports.
NOTE 2—The NIST Standard PS 20-70 is given as an example of a
The specimen is loaded at a prescribed rate and, as applicable,
product standard applicable to stress-graded lumber. Other product stan-
dards may apply to stress-graded lumber. For wood-base structural
observation of load or deflection, or both, is made until failure
materials other than stress-graded lumber, relevant product standards may
occurs or a preselected load is reached.
apply.
8. Apparatus
3. Terminology
8.1 Testing Machine—A device that combines (1) a reaction
3.1 Definitions—See Terminologies D 9 and E 6 and Prac-
frame to support the test specimen, (2) a loading mechanism
tices E 4 and E 177 for definitions of terms used in these test
for applying load at a specified rate, and (3) a force-measuring
methods.
apparatus that can be calibrated to the accuracy requirements of
3.2 Definitions of Terms Specific to This Standard:
8.3.2 following the procedures outlined in Practices E 4.
3.2.1 breadth—that dimension of the test specimen in the
8.1.1 Load and Support Apparatus, including bearing plates
direction perpendicular to the span and perpendicular to the
at least as wide as the specimen is broad and not exceeding 8
direction of an applied bending load.
in. (200 mm) in length. It is recommended that, under this test
3.2.2 depth—that dimension of the test specimen in the
method, the bearing plate length of the loading apparatus be no
direction perpendicular to the span and parallel to the direction
less than one half the specimen depth. The apparatus shall also
of an applied bending load.
include appropriate mechanisms such as rollers or pivots to
3.2.3 span—the distance between the center lines of end
minimize the development of axial forces in the test specimen.
reactions on which the test specimen is supported to accom-
8.1.2 Loading Configuration—The simply supported test
modate a transverse bending load or, for tension loading, the
specimen shall be subjected to two equal transverse concen-
distance between the grips.
trated loads spaced equidistant from the supports.
4. Significance and Use
NOTE 3—The apparent modulus of elasticity varies for different loading
configurations (see Practice D 2915). While the loading configuration
4.1 These test methods provide procedures that are appli-
which commonly serves as the basis for assigning design values assumes
cable under true field conditions such as in a plant with
a uniformly distributed load, a configuration with two concentrated loads
specimens not at moisture equilibrium.
symmetrically placed within the test span usually is more suitable for
4.2 The data established by these test methods can be used
structural tests. This configuration also produces a constant bending
as follows:
moment, free of shear, in the portion of the specimen between the load
4.2.1 Develop strength and stiffness properties for the popu-
points.
lation represented by the material being tested (that is, indi-
8.1.3 Lateral Supports, when necessary, to restrict the
vidual grades, grade combinations, species, species groups, or
specimen lateral deflection. Specimens having a depth-to-
any other defined, identifiable sample).
breadth ratio of three or greater are subject to lateral instability
4.2.2 Confirm the validity of strength and stiffness proper-
during loading and may require lateral supports. These sup-
ties for the population represented by the material being tested.
ports shall allow movement of the specimen in the direction of
4.2.3 Investigate the effect of parameters which may influ-
load application and have minimal frictional restraint.
ence the strength and stiffness properties of the material, such
8.2 Deflection Measuring Apparatus, for modulus of elas-
as moisture content, temperature, knot size and location, or
ticity calculations, to monitor the deflection of the test speci-
slope of grain.
men. Deflection may be measured directly as the displacement
4.3 The procedures chosen in accordance with these test
of the loading head of the testing machine. In this case,
methods shall be fully documented in the report to facilitate
deflection is expressed as the average deflection of the load
correlation with test results obtained through the use of
points with respect to the end reaction plates. If, because of the
traditional procedures such as set forth in Methods D 198.
design of the apparatus, the deflection measurement includes
extraneous components, the deflection data may be adjusted for
5. Precision and Bias
such extraneous components (Note 4). In all instances, the
5.1 The precision and bias of these test methods have not
report shall include a complete description of test conditions,
yet been established.
extraneous components, and data adjustment procedures.
BENDING EDGE-WISE
NOTE 4—If the extraneous components are an appreciable portion of
the total measurement, the test apparatus should be reexamined for its
6. Scope
suitability.
6.1 This test method provides procedures for the determi-
8.3 Accuracy:
nation of the strength and modulus of elasticity of stress-graded
8.3.1 The two load points shall be located within ⁄8 in. (3
lumber and other wood-base structural material in bending
mm) of the distance determined in accordance with 8.1.2 and
edge-wise.
9.2.2.
8.3.2 The force-measuring apparatus shall be such as to
6 permit load measurements with an error not to exceed 61.0 %
Available from National Institute of Standards and Technology, 100 Bureau Dr.,
Stop 3460, Gaithersburg, MD 20899-3460. of the load for loads greater than or equal to 1000 lbf (4450 N).
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 4761
For loads smaller than 1000 lbf, the error shall not exceed 610 10.2.2 Selection of the Tension Edge—Randomly select the
lbf (45 N). edge to be subjected to tension testing.
8.3.3 The deflection measuring apparatus shall be such as to 10.3 Speed of Testing—The test rate shall be such that the
permit deflection measurements with an error not to exceed sample target failure load would be achieved in approximately
62.0 % of the deflection for deflections greater than or equal to 1 min (Note 6). The failure load should not be reached in less
0.150 in. (4 mm). For deflections smaller than 0.150 in., the than 10 s nor more than 10 min (Note 7).
error shall not exceed 60.003 in. (0.08 mm).
NOTE 6—Some caution is warranted here. A test rate to achieve the
average failure load for the sample in approximately 1 min will differ from
9. Test Specimen
that to achieve a lower percentile load for the same sample in approxi-
9.1 Cross Section—Unless the effect of cross-section modi-
mately 1 min.
fications is a test evaluation objective, test the specimen
NOTE 7—For stress-graded lumber, a rate of motion of the testing
without modifying the dimensions of the commercial cross machine loading head of approximately 3 in. (75 mm)/min will usually
permit the test to be completed in the prescribed time for span to depth
section.
ratios of 17:1 and in cases where the target failure load is the average
9.2 Length:
failure load for the sample.
9.2.1 The minimum specimen length shall be the span,
10.4 Load-Deflection Data—Obtain load-deflection data, as
determined in accordance with 9.2.2, plus an extension beyond
required, using the apparatus specified in 8.2.
the center lines of the end reactions to accommodate the
bearing plates, such that the specimen will not slip off the end
NOTE 8—For stress-graded lumber, data obtained for loads correspond-
reactions during the test. In cases where the unsupported
ing to maximum stresses in the specimen ranging from 400 to 1000 psi
(2.75 to 7 MPa) will usually be adequate for modulus of elasticity
specimen length outside the test span at an end reaction
calculations.
(overhang) exceeds 10 times the specimen depth, report the
10.5 Maximum Load—If the purpose of the test is to
amount of overhang at each end reaction.
9.2.2 The span will depend on the purpose of the test determine strength properties, record the maximum load at-
tained in the test.
program. It is customary to express the span as a multiple of
the test specimen depth (Note 5). While spans, which currently
NOTE 9—In proof loading, the intended load target may not be reached
serve as a basis suitable for testing range from 17 times the
or may be exceeded slightly. The actual attained load as well as the target
depth of the specimen to 21 times the depth, other spans may
load should therefore be recorded.
be used under this test method. Practice D 2915 gives an
10.6 Record of Failure—Depending on the purpose of the
indication of the variation of the apparent modulus of elasticity
test, a description of the characteristic causing failure, and its
with span to depth ratios.
location within the test span, may be required.
NOTE 5—The depth here refers to the relevant size specified in the size
NOTE 10—An example of a coding scheme for recording characteristic
classification of the applicable product standard (for stress-graded lumber,
type and failure location is given in Appendix X1. This example was
for example, the depth here may refer to the dressed dry size specified in
derived for application to stress-graded lumber.
the size classification of the American Softwood Lumber Standard for the
11. Report
nominal size, for example, 3.5 in. (89 mm) for a nominal 4 in.).
11.1 The report content depends on the purpose of the test
9.3 Conditioning—Specimens may be tested as produced or
program. The report shall include, at the minimum, the
conditioned (for example, temperature, moisture content, or
following information:
treatment), depending on the purpose of the test program. If the
11.1.1 Description of the testing machine, including detailed
temperature of the specimens at the time of testing is less than
drawings, the span, and the deflection measuring apparatus, if
45°F (7°C) or more than 90°F (32°C), report that temperature.
applicable.
10. Procedure
11.1.2 Description of calibr
...