ASTM D7914/D7914M-21
(Test Method)Standard Test Method for Strength of Fiber Reinforced Polymer (FRP) Bent Bars in Bend Locations
Standard Test Method for Strength of Fiber Reinforced Polymer (FRP) Bent Bars in Bend Locations
SIGNIFICANCE AND USE
5.1 This test method is intended to determine the bend strength of FRP composite concrete reinforcements, developed at a standard twelve bar diameters of embedment. From this test, a variety of data are acquired that are needed for design purposes. Material-related factors that influence the tensile response of bars include the following: constituent materials, void content, volume percent reinforcement, methods of fabrication, and fiber reinforcement architecture. Similarly, factors relevant to the measured tensile response of bars include specimen preparation, specimen conditioning, environment of testing, specimen alignment, and speed of testing. The results may be used for material specifications, research and development, and structural design and analysis.
Note 1: Two FRP bends are tested simultaneously in this test method, but in some cases, only one bend may fail. While resulting in a valid failure, notice should be taken that only one bend has been effectively measured and that the final compiled test results using this method could differ from those resulting from single FRP bend testing.
SCOPE
1.1 This test method determines the quasi-static ultimate strength of fiber reinforced polymer (FRP) composite bent bars commonly used as anchorages for stirrups in reinforced, prestressed, or post-tensioned concrete structures. This test method only applies to bars with a solid cross section.
1.2 FRP bent bars are often used in reinforced concrete applications to shorten the development length of the bar or to act as a tie or a stirrup to resist shear forces. Bent bars can be produced with varying angles of bend in order to fit their intended purpose.
1.3 For this test method, the FRP bars are bent at a 90 degree angle. In general, bars have a regular pattern of surface undulations, a coating of bonded particles, or both, that promote mechanical interlock between the bar and concrete.
1.4 This test method may be completed on standardized bars, produced according to Specification D7957/D7957M. In this case, the nominal cross-sectional areas and effective diameters are taken from D7957/D7957M. This test method may also be used for bars that are not standardized. In this case, the cross-sectional areas and effective diameters should be measured 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 for sustained static or cyclic loading. If bars are to be used under high levels of sustained or repeated loading, additional material characterization may be required.
1.6 The characteristic values obtained from this test method are intended to represent the quasi-static ultimate strength of FRP bent bars with a tail length of twelve bar diameters.
1.7 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
1.7.1 Within the text, the inch-pound units are shown in brackets.
1.8 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7914/D7914M −21
Standard Test Method for
Strength of Fiber Reinforced Polymer (FRP) Bent Bars in
1
Bend Locations
This standard is issued under the fixed designation D7914/D7914M; 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.
1. Scope lents; therefore, to ensure conformance with the standard, each
system shall be used independently of the other, and values
1.1 This test method determines the quasi-static ultimate
from the two systems shall not be combined.
strengthoffiberreinforcedpolymer(FRP)compositebentbars
1.7.1 Within the text, the inch-pound units are shown in
commonly used as anchorages for stirrups in reinforced,
brackets.
prestressed, or post-tensioned concrete structures. This test
1.8 This standard does not purport to address all of the
method only applies to bars with a solid cross section.
safety concerns, if any, associated with its use. It is the
1.2 FRP bent bars are often used in reinforced concrete
responsibility of the user of this standard to establish appro-
applications to shorten the development length of the bar or to
priate safety, health, and environmental practices and deter-
act as a tie or a stirrup to resist shear forces. Bent bars can be
mine the applicability of regulatory limitations prior to use.
produced with varying angles of bend in order to fit their
1.9 This international standard was developed in accor-
intended purpose.
dance with internationally recognized principles on standard-
1.3 For this test method, the FRP bars are bent at a 90
ization established in the Decision on Principles for the
degree angle. In general, bars have a regular pattern of surface
Development of International Standards, Guides and Recom-
undulations, a coating of bonded particles, or both, that
mendations issued by the World Trade Organization Technical
promote mechanical interlock between the bar and concrete.
Barriers to Trade (TBT) Committee.
1.4 This test method may be completed on standardized
2. Referenced Documents
bars, produced according to Specification D7957/D7957M.In
2
this case, the nominal cross-sectional areas and effective
2.1 ASTM Standards:
diameters are taken from D7957/D7957M. This test method
C39/C39MTest Method for Compressive Strength of Cylin-
mayalsobeusedforbarsthatarenotstandardized.Inthiscase,
drical Concrete Specimens
the cross-sectional areas and effective diameters should be
C143/C143MTest Method for Slump of Hydraulic-Cement
measured and calculated as described in Test Method D7205/
Concrete
D7205M.
C192/C192MPracticeforMakingandCuringConcreteTest
Specimens in the Laboratory
1.5 The strength values provided by this method are short-
D883Terminology Relating to Plastics
term, quasi-static tensile strengths that do not account for
D3878Terminology for Composite Materials
sustained static or cyclic loading. If bars are to be used under
D5229/D5229MTestMethodforMoistureAbsorptionProp-
highlevelsofsustainedorrepeatedloading,additionalmaterial
erties and Equilibrium Conditioning of Polymer Matrix
characterization may be required.
Composite Materials
1.6 The characteristic values obtained from this test method
D7205/D7205MTest Method forTensile Properties of Fiber
are intended to represent the quasi-static ultimate strength of
Reinforced Polymer Matrix Composite Bars
FRP bent bars with a tail length of twelve bar diameters.
D7957/D7957MSpecification for Solid Round Glass Fiber
1.7 Units—The values stated in either SI units or inch-
Reinforced Polymer Bars for Concrete Reinforcement
pound units are to be regarded separately as standard. The
E4Practices for Force Verification of Testing Machines
values stated in each system are not necessarily exact equiva-
E6Terminology Relating to Methods of Mechanical Testing
E122PracticeforCalculatingSampleSizetoEstimate,With
1
This test method is under the jurisdiction of ASTM Committee D30 on
Composite Materials and is the direct responsibility of Subcommittee D30.10 on
2
Composites for Civil Structures. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2021. Published February 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2014. Last previous edition approved in 2014 as D7914/D7914M–14. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D7914_D7914M-21. the ASTM website.
Copyright © ASTM International, 10
...
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: D7914/D7914M − 14 D7914/D7914M − 21
Standard Test Method for
Strength of Fiber Reinforced Polymer (FRP) Bent Bars in
1
Bend Locations
This standard is issued under the fixed designation D7914/D7914M; 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.
1. Scope
1.1 This test method determines the quasi-static ultimate strength of fiber reinforced polymer (FRP) composite bent bars
commonly used as anchorages for stirrups in reinforced, prestressed, or post-tensioned concrete structures. This test method only
applies to bars with a solid cross section.
1.2 FRP bent bars are often used in reinforced concrete applications to shorten the development length of the bar or to act as a
tie or a stirrup to resist shear forces. Bent bars can be produced with varying angles of bend in order to fit their intended purpose.
1.3 For this test method, the FRP bars are bent at a 90 degree angle. In general, bars have a regular pattern of surface undulations,
a coating of bonded particles, or both, that promote mechanical interlock between the bar and concrete.
1.4 This test method may be completed on standardized bars, produced according to Specification D7957/D7957M. In this case,
the nominal cross-sectional areas and effective diameters are taken from D7957/D7957M. This test method may also be used for
bars that are not standardized. In this case, the cross-sectional areas and effective diameters should be measured 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 for sustained
static or cyclic loading. If bars are to be used under high levels of sustained or repeated loading, additional material characterization
may be required.
1.6 The characteristic values obtained from this test method are intended to represent the quasi-static ultimate strength of FRP bent
bars with a tail length of twelve bar diameters.
1.7 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in
each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
1.7.1 Within the text, the inch-pound units are shown in brackets.
1.8 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1
This test method is under the jurisdiction of ASTM Committee D30 on Composite Materials and is the direct responsibility of Subcommittee D30.10 on Composites
for Civil Structures.
Current edition approved Aug. 1, 2014Jan. 1, 2021. Published December 2014February 2021. Originally approved in 2014. Last previous edition approved in 2014 as
D7914/D7914M – 14. DOI: 10.1520/D7914_D7914M-14.10.1520/D7914_D7914M-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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D7914/D7914M − 21
1.9 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
A615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
C39/C39M Test Method for Compressive Strength of Cylindrical Concrete Specimens
C143/C143M Test Method for Slump of Hydraulic-Cement Concrete
C192/C192M Practice for Making and Curing Concrete Test Specimens in the Laboratory
D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement
D883 Terminology Relating to Plastics
D3171 Test Methods for Constituent Content of Composite Materials
D3878 Terminology for Composite Materials
D5229/D5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning
...
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