ASTM_D_7914_-_D_7914M_-_21.pdf

Designation:D7914/D7914M21Standard Test Method forStrength of Fiber Reinforced Polymer(FRP)Bent Bars inBend Locations1This standard is issued under the fixed designation D7914/D7914M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method determines the quasi-static ultimatestrength of fiber reinforced polymer(FRP)composite bent barscommonly used as anchorages for stirrups in reinforced,prestressed,or post-tensioned concrete structures.This testmethod only applies to bars with a solid cross section.1.2 FRP bent bars are often used in reinforced concreteapplications to shorten the development length of the bar or toact as a tie or a stirrup to resist shear forces.Bent bars can beproduced with varying angles of bend in order to fit theirintended purpose.1.3 For this test method,the FRP bars are bent at a 90degree angle.In general,bars have a regular pattern of surfaceundulations,a coating of bonded particles,or both,thatpromote mechanical interlock between the bar and concrete.1.4 This test method may be completed on standardizedbars,produced according to Specification D7957/D7957M.Inthis case,the nominal cross-sectional areas and effectivediameters are taken from D7957/D7957M.This test methodmay also be used for bars that are not standardized.In this case,the cross-sectional areas and effective diameters should bemeasured and calculated as described in Test Method D7205/D7205M.1.5 The strength values provided by this method are short-term,quasi-static tensile strengths that do not account forsustained static or cyclic loading.If bars are to be used underhigh levels of sustained or repeated loading,additional materialcharacterization may be required.1.6 The characteristic values obtained from this test methodare intended to represent the quasi-static ultimate strength ofFRP bent bars with a tail length of twelve bar diameters.1.7 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard.Thevalues stated in each system are not necessarily exact equiva-lents;therefore,to ensure conformance with the standard,eachsystem shall be used independently of the other,and valuesfrom the two systems shall not be combined.1.7.1 Within the text,the inch-pound units are shown inbrackets.1.8 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is 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.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-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:2C39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC143/C143M Test Method for Slump of Hydraulic-CementConcreteC192/C192M Practice for Making and Curing Concrete TestSpecimens in the LaboratoryD883 Terminology Relating to PlasticsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsD7205/D7205M Test Method for Tensile Properties of FiberReinforced Polymer Matrix Composite BarsD7957/D7957M Specification for Solid Round Glass FiberReinforced Polymer Bars for Concrete ReinforcementE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE122 Practice for Calculating Sample Size to Estimate,With1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.10 onComposites for Civil Structures.Current edition approved Jan.1,2021.Published February 2021.Originallyapproved in 2014.Last previous edition approved in 2014 as D7914/D7914M 14.DOI:10.1520/D7914_D7914M-21.2For 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,West 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.1Specified Precision,t