ASTM D2555-98e1

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Designation:D2555–98
Standard Test Methods for
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Establishing Clear Wood Strength Values
This standard is issued under the fixed designation D 2555; 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.
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e NOTE—Table 1 footnotes were corrected editorially in May 2003.
INTRODUCTION
The development of safe and efficient working stresses for lumber, laminated timber, plywood,
round timbers, and other solid wood products, each with its own special requirements has, as a
common starting point, the need for an authoritative compilation of clear wood strength values for the
commercially important species.Also required are procedures for establishing, from these data, values
applicable to groups of species or to regional groupings within a species where necessitated by
marketing conditions. This standard has been developed to meet these needs and to provide, in
addition, information on factors for consideration in the adjustment of the clear wood strength values
tothelevelofworkingstressesfordesign.Sincefactorssuchasspeciespreference,speciesgroupings,
marketing practices, design techniques, and safety factors vary with each type of product and end use,
it is contemplated that this standard will be supplemented where necessary by other appropriate
standardsrelatingtospecificworkstressesforeachsuchproduct.ASTMPracticeD 245isanexample
of such a standard applicable to the interpretation of the clear wood strength values in terms of
working stresses for structural lumber.
A primary feature of this standard is the establishment of tables presenting the most reliable basic
information developed on the strength of clear wood and its variability through many years of testing
and experience. The testing techniques employed are those presented in Methods D 143. Among the
recognizedlimitationsofsuchstrengthdataarethoseresultingfromtheproblemsofsamplingmaterial
from forests extending over large regions, and the uneconomical feasibility of completely testing an
intensive sample.Apractical approach to the improvement of strength data is through the application
of the results of density surveys in which the specific gravity of the entire forest stand for each species
is determined on a sound statistical basis. Through regression equations derived from presently
available strength data, revised strength values are established from the specific gravity-strength
relationship for clear wood. This procedure greatly extends current capabilities to develop new
estimates of strength and to improve or verify estimates made in the past.
1. Scope 1.1.2 Guidelinesfortheinterpretationofthedataintermsof
assigned values for combinations of species or regional divi-
1.1 These test methods cover the determination of strength
sions within a species to meet special marketing needs, and
values for clear wood of different species in the unseasoned
1.1.3 Information basic to the translation of the clear wood
condition, unadjusted for end use, applicable to the establish-
values into working stresses for different solid wood products
mentofworkingstressesfordifferentsolidwoodproductssuch
for different end uses.
as lumber, laminated wood, plywood, and round timbers.
1.1.4 For species where density survey data are not as yet
Presented are:
available for the reevaluation of average strength properties,
1.1.1 Procedures by which test values obtained on small
thepresentlyavailabledatafromtestsmadeunderthesampling
clear specimens may be combined with density data from
methods and procedures of Methods D 143, or Practice E 105,
extensive forest surveys to make them more representative,
are provided with appropriate provision for their application
and use. Because of the comprehensive manner in which the
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These test methods are under the jurisdiction of ASTM Committee D07 on
density survey is undertaken, it follows that the reevaluated
Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental
strength data are intended to be representative of the forest
Test Methods and Properties.
stand, or rather large forest subdivisions.
Current edition approved July 10, 1998. Published March 1999. Originally
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published as D 2555 – 66 T. Last previous edition D 2555 – 96 .
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D2555–98
1.1.5 Some useful mechanical properties (tensile strengths these methods a basic group is a combination of unit areas
parallel and perpendicular to grain and modulus of rigidity for representin
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