1、Designation:D289912(Reapproved 2017)Standard Practice forEstablishing Allowable Stresses for Round Timber Piles1This standard is issued under the fixed designation D2899;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of las
2、t revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice contains procedures for establishing allow-able stresses for round timber piles starting with clear woodstrength
3、 properties.1.2 Stresses established under this practice are applicable topiles conforming to the quality,straightness,spiral grain,knot,check,shake,and split provisions of Specification D25.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is
4、theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standa
5、rd-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D25 Specification for Round Timber PilesD245 Practi
6、ce for Establishing Structural Grades and Re-lated Allowable Properties for Visually Graded LumberD2555 Practice for Establishing Clear Wood Strength Values3.Terminology3.1 Definitions:3.1.1 allowable stressthe numeric value of pile strengththat is appropriate for use in structural analysis.3.1.2 en
7、d-bearingcompression-parallel-to-the-grain stressresulting when pile load is not carried to the soil through skinfriction.3.1.3 load sharingthe distribution of load in proportion topile stiffness.This results in piles that perform as a groupreducing effects of between-pile variability and increasing
8、system reliability over that of piles which perform indepen-dently.3.1.4 skin frictionthe interaction between the pile surfaceand the soil which serves to distribute load either away from orinto a pile.A positive skin friction refers to pile loadsdistributed to the soil.Negative skin friction distri
9、butes load tothe pile when soil strata subside or consolidate.3.2 Symbols:Ccp=adjustment for small clear compressionperp for annual ring orientation(1/1.67)Cct=conditioning factorCdol=adjustment for duration of load and factor of safetyCd=adjustment for density applied for Douglas fir andSouthern pi
10、ne onlyCfs=combined adjustment for form and size(=0.97)Cg=adjustment for grade characteristics applied to allspecies including bending(0.75),compression(0.93),andshear(0.50)Ch=adjustment for height in the tree(=0.96 if softwoodsand=1.0 for hardwoods)Chv=adjustment for height and for reduced variabil
11、ity(MOR=0.91 for softwoods,1.05 for hardwoods,C/=0.91 forsoftwoods,1.05 for hardwoods,Shear=0.99 for softwoods,1.03 for hardwoods)Cls=load sharing adjustment(structural engineers option)Cs=size adjustmentCv=adjustment for shear deflection in calculation for bend-ing modulus of elasticity(=1.06)D=dia
12、meter of a round timber pileE=clear wood unseasoned average modulus of elasticityfrom Test Methods D2555MOE=modulus of elasticity(average)F=allowable stress for stress designated by the subscript Fc=allowable compression stress for pile tipsfc05=small clear lower 5%exclusion compression strengthin a
13、ccordance with Test Methods D2555fi05=lower 5%exclusion value for stress“x”determinedusing the green,small clear strength and standard deviationvalues reported in Test Methods D2555=stress value subscripts,c=compression parallel,cp=compression perpendicular,b=bending,v=shear1This practice is under t
14、he jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility of Subcommittee D07.04 on Pole and Pile Products.Current edition approved Oct.1,2017.Published October 2017.Originallyapproved in 1970 as D2899 70 T.Last previous edition approved in 2012 asD2899 12.DOI:10.1520/D2899-12R17
15、.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,We
16、st Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 4.Significance and Use4.1 This practice is intended for use by associations,tech-nical societies and other groups that develop national desig