ASTM D2555-15

Standard Practice for Establishing Clear Wood Strength Values

ABSTRACT
This practice presents the two standard methods for determining the strength values of clear wood of different species in the unseasoned condition, unadjusted for end use, applicable to the establishment of working stresses for different solid wood products such as lumber, laminated wood, plywood, and round timbers. Method A provides for the use of the results of surveys of wood density involving extensive sampling of forest trees, in combination with the data obtained from standard strength tests. The average strength properties are obtained from wood density survey data through linear regression equations establishing the relation of specific gravity to the several strength properties. Method B, on the other hand, provides for the establishment of tables of strength values based on standard tests of small clear specimens in the unseasoned condition for use when data from density surveys are not available. Separate tables are employed to present the data on woods grown in the United States and on woods grown in Canada. Guidelines for the interpretation of the data in terms of assigned values, information basic to the translation of the clear wood values into working stresses, presently available data with appropriate provisions for their application and use, and methods for estimating some useful mechanical properties by relating them to other properties are presented herein as well.
SCOPE
1.1 This practice covers the determination of strength values for clear wood of different species in the unseasoned condition, unadjusted for end use, applicable to the establishment of working stresses for different solid wood products such as lumber, laminated wood, plywood, and round timbers. Presented are:  
1.1.1 Procedures by which test values obtained on small clear specimens may be combined with density data from extensive forest surveys to make them more representative,  
1.1.2 Guidelines for the interpretation of the data in terms of assigned values for combinations of species or regional divisions within a species to meet special marketing needs, and  
1.1.3 Information basic to the translation of the clear wood values into working stresses for different solid wood products for different end uses.  
1.1.4 For species where density survey data are not as yet available for the re-evaluation of average strength properties, the presently available data from tests made under the sampling methods and procedures of Test Methods D143 or Practice E105 are provided with appropriate provision for their application and use. Because of the comprehensive manner in which the density survey is undertaken, it follows that the re-evaluated strength data are intended to be representative of the forest stand, or rather large forest subdivisions.  
1.1.5 Some useful mechanical properties (tensile strengths parallel and perpendicular to grain, modulus of rigidity for a longitudinal-transverse plane, and transverse modulus of elasticity) have not been extensively evaluated. Methods are described for estimating these properties by their relation to other properties.  
1.2 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: 31-Aug-2015
• ICS: 79.040 - Wood, sawlogs and sawn timber
• Technical Committee: D07 - Wood
• Drafting Committee: D07.01 - Fundamental Test Methods and Properties

Relations

• Replaces: ASTM D2555-06(2011) - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 01-Sep-2015
• Replaced By: ASTM D2555-16 - Standard Practice for Establishing Clear Wood Strength Values
• Effective Date: 01-Aug-2016
• Referred By: ASTM D2559-12a(2018) - Standard Specification for Adhesives for Bonded Structural Wood Products for Use Under Exterior Exposure Conditions
• Effective Date: 01-Sep-2015
• Referred By: ASTM D3957-09(2020) - Standard Practices for Establishing Stress Grades for Structural Members Used in Log Buildings
• Effective Date: 01-Sep-2015
• 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: 01-Sep-2015
• Referred By: ASTM D245-22 - Standard Practice for Establishing Structural Grades and Related Allowable Properties for Visually Graded Lumber
• Effective Date: 01-Sep-2015
• Referred By: ASTM D6570-18a(2023)e1 - Standard Practice for Assigning Allowable Properties for Mechanically Graded Lumber
• Effective Date: 01-Sep-2015
• Referred By: ASTM D1990-19 - Standard Practice for Establishing Allowable Properties for Visually-Graded Dimension Lumber from In-Grade Tests of Full-Size Specimens
• Effective Date: 01-Sep-2015
• Referred By: ASTM D2395-17(2022) - Standard Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials
• Effective Date: 01-Sep-2015
• Referred By: ASTM D25-12(2022) - Standard Specification for Round Timber Piles
• Effective Date: 01-Sep-2015
• Referred By: ASTM D2915-17(2022) - Standard Practice for Sampling and Data-Analysis for Structural Wood and Wood-Based Products
• Effective Date: 01-Sep-2015
• Referred By: ASTM D9-20 - Standard Terminology Relating to Wood and Wood-Based Products
• Effective Date: 01-Sep-2015
• Referred By: ASTM D3737-18e1 - Standard Practice for Establishing Allowable Properties for Structural Glued Laminated Timber (Glulam)
• Effective Date: 01-Sep-2015
• Referred By: ASTM D5574-94(2021) - Standard Test Methods for Establishing Allowable Mechanical Properties of Wood-Bonding Adhesives for Design of Structural Joints
• Effective Date: 01-Sep-2015
• Referred By: ASTM D5536-17(2023) - Standard Practice for Sampling Forest Trees for Determination of Clear Wood Properties
• Effective Date: 01-Sep-2015

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D2555 − 15
StandardPractice for
1
Establishing Clear Wood Strength Values
This standard is issued under the fixed designation D2555; 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.
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
commerciallyimportantspecies.Alsorequiredareproceduresforestablishing,fromthesedata,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.PracticeD245isanexampleofsuch
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 practice 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 Test Methods D143. Among
the recognized limitations of such strength data are those resulting from the problems of sampling
material from forests extending over large regions, and the uneconomical feasibility of completely
testing an intensive sample. A practical 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 Thispracticecoversthedeterminationofstrengthvalues
sions within a species to meet special marketing needs, and
forclearwoodofdifferentspeciesintheunseasonedcondition,
1.1.3 Information basic to the translation of the clear wood
unadjusted for end use, applicable to the establishment of
values into working stresses for different solid wood products
working stresses for different solid wood products such as
for different end uses.
lumber, laminated wood, plywood, and round timbers. Pre-
1.1.4 For species where density survey data are not as yet
sented are:
available for the re-evaluation 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 Test Methods D143 or Practice
extensive forest surveys to make them more representative,
E105 are provided with appropriate provision for their appli-
cationanduse.Becauseofthecomprehensivemannerinwhich
1 the density survey is undertaken, it follows that the re-
This practice is under the jurisdiction of ASTM Committee D07 on Wood and
are the direct responsibility of Subcommittee D07.01 on FundamentalTest Methods evaluated strength data are intended to be representative of the
and Properties.
forest stand, or rather large forest subdivisions.
Current edition approved Sept. 1, 2015. Published December 2015. Originally
1.1.5 Some useful mechanical properties (tensile strengths
approved in 1966. Last previous edition approved in 2011 as D2555 – 06(2011).
DOI: 10.1520/D2555-15. parallel and perpendicular to grain, modulus of rigidity for a
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D2555 − 15
longitudinal-transverse plane, and transverse modulus of elas- these methods a basic group is a combination of unit areas
ticit
...

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: D2555 − 06 (Reapproved 2011) D2555 − 15
Standard Practice for
1
Establishing Clear Wood Strength Values
This standard is issued under the fixed designation D2555; 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.
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
to the level of working stresses for design. Since factors such as species preference, species groupings,
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
standards relating to specific work stresses for each such product. Practice D245 is an example 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 practice 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 Test Methods D143. Among
the recognized limitations of such strength data are those resulting from the problems of sampling
material from forests extending over large regions, and the uneconomical feasibility of completely
testing an intensive sample. A practical 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 This practice covers the determination of strength values for clear wood of different species in the unseasoned condition,
unadjusted for end use, applicable to the establishment of working stresses for different solid wood products such as lumber,
laminated wood, plywood, and round timbers. Presented are:
1.1.1 Procedures by which test values obtained on small clear specimens may be combined with density data from extensive
forest surveys to make them more representative,
1.1.2 Guidelines for the interpretation of the data in terms of assigned values for combinations of species or regional divisions
within a species to meet special marketing needs, and
1.1.3 Information basic to the translation of the clear wood values into working stresses for different solid wood products for
different end uses.
1.1.4 For species where density survey data are not as yet available for the re-evaluation of average strength properties, the
presently available data from tests made under the sampling methods and procedures of Test Methods D143 or Practice E105 are
1
This practice is under the jurisdiction of ASTM Committee D07 on Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental Test Methods and
Properties.
Current edition approved Oct. 1, 2011Sept. 1, 2015. Published October 2011December 2015. Originally approved in 1966. Last previous edition approved in 20062011
as D2555 – 06.D2555 – 06(2011). DOI: 10.1520/D2555-06R11.10.1520/D2555-15.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D2555 − 15
provided with appropriate provision for their application and use. Because of the comp
...