ASTM C1531-22

Standard Test Methods for In Situ Measurement of Masonry Mortar Joint Shear Strength Index

SIGNIFICANCE AND USE
5.1 This test method provides a means of evaluating the horizontal in-plane shear behavior of mortar joints in existing unreinforced masonry assemblies (see Note 2).
Note 2: The masonry mortar joint shear strength index obtained by this test method can be related to the masonry wall shear strength by relationships contained in referencing Codes and Standards. For example, formulas relating shear index to wall shear strength are found in Chapter A1 of the International Existing Building Code and Chapter 11 of the Seismic Evaluation and Retrofit of Existing Buildings, ASCE Standard ASCE/SEI 41. The user of this standard is cautioned that these shear strength relationships are typically empirical relationships based on tests of early 20th-century unreinforced brick masonry. These relationships typically assume that wall shear strength is limited by shear of the mortar joints rather than shear through the units  
5.2 For hollow ungrouted or solid unit masonry construction the shear strength index is measured only for the mortar bed joints vertically adjacent to the unit being tested. When testing hollow ungrouted masonry construction, the shear strength index is based on the horizontal interface between the mortar and the test unit and the masonry above and below the test unit. In the case of multi-wythe construction, the measured mortar joint shear strength index is applicable only to the wythe in which the test unit is located; no headers shall exist immediately above or below the test unit. The contribution of any existing collar joint mortar to the measured shear strength index is neglected, and this may lead to an overestimate of the shear strength index (see Note 3).
Note 3: Some documents that reference this test method, including ASCE/SEI 41, include a reduction factor to account for the contribution of a filled collar joint to the measured shear strength index.  
5.3 The test procedure listed for Method A may be conducted as an extension of Test Method C1...
SCOPE
1.1 These test methods cover procedures for the determination of the average in situ mortar joint shear strength index in existing unreinforced solid-unit and ungrouted hollow-unit masonry built with clay or concrete units. Three methods are provided:  
1.1.1 Method A (with Flatjacks Controlling Normal Compressive Stress)—For determining mortar joint shear strength index when the state of normal compressive stress at the test site is controlled during the test using the flatjack method described in Test Method C1197. Horizontal displacement of the test unit is monitored throughout the test. The test setup for Method A is shown in Fig. 1.
FIG. 1 Test Setup—Method A  
Note 1: A paper2 by Francesco Graziotti et. al of Univ. of Pavia included in ASTM STP 1612 discusses alternative methods for interpreting Method A testing results.  
1.1.2 Method B (without Flatjacks Controlling Normal Compressive Stress)—For determining mortar joint shear strength index when using an estimate of the normal compressive stress at the location of the test site. Horizontal displacement of the test unit is not monitored during this procedure. The test set up for Method B is shown in Fig. 2.
FIG. 2 Test Setup—Method B  
1.1.3 Method C (with Flatjack Applying Horizontal Load)—For determining mortar joint shear strength index using an estimate of the normal compressive stress at the location of the test site, as shown in Fig. 3. Horizontal displacement of the test unit is generally not measured during this procedure.
FIG. 3 Test Setup—Method C  
1.2 The text of this standard refers to notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.  
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for informat...

General Information

• Status: Published
• Publication Date: 30-Nov-2022
• ICS: 91.080.30 - Masonry
• Technical Committee: C15 - Manufactured Masonry Units
• Drafting Committee: C15.04 - Research

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: C1531 − 22
Standard Test Methods for
In Situ Measurement of Masonry Mortar Joint Shear
1
Strength Index
This standard is issued under the fixed designation C1531; 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* 1.3 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
1.1 These test methods cover procedures for the determina-
conversions to SI units that are provided for information only
tion of the average in situ mortar joint shear strength index in
and are not considered standard.
existing unreinforced solid-unit and ungrouted hollow-unit
1.4 This standard does not purport to address all of the
masonry built with clay or concrete units. Three methods are
safety concerns, if any, associated with its use. It is the
provided:
responsibility of the user of this standard to establish appro-
1.1.1 Method A (with Flatjacks Controlling Normal Com-
priate safety, health, and environmental practices and deter-
pressive Stress)—For determining mortar joint shear strength
mine the applicability of regulatory limitations prior to use.
index when the state of normal compressive stress at the test
1.5 This international standard was developed in accor-
site is controlled during the test using the flatjack method
dance with internationally recognized principles on standard-
described in Test Method C1197. Horizontal displacement of
ization established in the Decision on Principles for the
the test unit is monitored throughout the test.The test setup for
Development of International Standards, Guides and Recom-
Method A is shown in Fig. 1.
mendations issued by the World Trade Organization Technical
2
NOTE 1—A paper by Francesco Graziotti et. al of Univ. of Pavia
Barriers to Trade (TBT) Committee.
included in ASTM STP 1612 discusses alternative methods for interpret-
ing Method A testing results.
2. Referenced Documents
1.1.2 Method B (without Flatjacks Controlling Normal
3
2.1 ASTM Standards:
Compressive Stress)—For determining mortar joint shear
C1180 Terminology of Mortar and Grout for Unit Masonry
strength index when using an estimate of the normal compres-
C1196 Test Method for In Situ Compressive Stress Within
sive stress at the location of the test site. Horizontal displace-
Solid Unit Masonry Estimated Using Flatjack Measure-
ment of the test unit is not monitored during this procedure.
ments
The test set up for Method B is shown in Fig. 2.
C1197 Test Method for In Situ Measurement of Masonry
1.1.3 MethodC(withFlatjackApplyingHorizontalLoad)—
Deformability Properties Using the Flatjack Method
For determining mortar joint shear strength index using an
C1232 Terminology for Masonry
estimate of the normal compressive stress at the location of the
E4 Practices for Force Calibration and Verification of Test-
testsite,asshowninFig.3.Horizontaldisplacementofthetest
ing Machines
unit is generally not measured during this procedure.
2.2 Other Document:
1.2 The text of this standard refers to notes and footnotes
International Existing Building Code (Appendix A, Chapter
that provide explanatory material. These notes and footnotes
A1, Seismic Strengthening Provisions for Unreinforced
4
(excluding those in tables and figures) shall not be considered
Masonry Bearing Wall Buildings), 2014
as requirements of the standard.
ASCE/SEI 41 Seismic Evaluation and Retrofit of Existing
Buildings, ASCE Standard ASCE/SEI 41 (Chapter 11,
5
Masonry)
1
These test methods are under the jurisdiction of ASTM Committee C15 on
Manufactured Masonry Units and are the direct responsibility of Subcommittee
3
C15.04 on Research. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2022. Published December 2022. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2002. Last previous edition approved in 2016 as C1531 – 16. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1531-22. the ASTM website.
2 4
Graziotti, F., Guerrini, G., Rossi,A.,Andreotti, G., and Magenes, G., “Proposal Available from International Code Council, 4051 Flossmoor Road, Country
for an Improved Procedure and Interpretation of ASTM C1531 for the In Situ Club Hills, IL 60478.
5
DeterminationofBrick-MasonryShearStrength,”Masonry2018,ASTMSTP1612, Available from American Society of Civil Engineers (ASCE)
...

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: C1531 − 16 C1531 − 22
Standard Test Methods for
In Situ Measurement of Masonry Mortar Joint Shear
1
Strength Index
This standard is issued under the fixed designation C1531; 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 These test methods cover procedures for the determination of the average in situ mortar joint shear strength index in existing
unreinforced solid-unit and ungrouted hollow-unit masonry built with clay or concrete units. Three methods are provided:
1.1.1 Method A (with Flatjacks Controlling Normal Compressive Stress)—For determining mortar joint shear strength index when
the state of normal compressive stress at the test site is controlled during the test using the flatjack method described in Test Method
C1197. Horizontal displacement of the test unit is monitored throughout the test. The test setup for Method A is shown in Fig. 1.
2
NOTE 1—A paper by Francesco Graziotti et. al of Univ. of Pavia included in ASTM STP 1612 discusses alternative methods for interpreting Method A
testing results.
1.1.2 Method B (without Flatjacks Controlling Normal Compressive Stress)—For determining mortar joint shear strength index
when using an estimate of the normal compressive stress at the location of the test site. Horizontal displacement of the test unit
is not monitored during this procedure. The test set up for Method B is shown in Fig. 2.
1.1.3 Method C (with Flatjack Applying Horizontal Load)—For determining mortar joint shear strength index using an estimate
of the normal compressive stress at the location of the test site, as shown in Fig. 3. Horizontal displacement of the test unit is
generally not measured during this procedure.
1.2 The text of this standard refers to notes and footnotes that provide explanatory material. These notes and footnotes (excluding
those in tables and figures) shall not be considered as requirements of the standard.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.4 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.
1.5 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.
1
These test methods are under the jurisdiction of ASTM Committee C15 on Manufactured Masonry Units and are the direct responsibility of Subcommittee C15.04 on
Research.
Current edition approved June 1, 2016Dec. 1, 2022. Published July 2016December 2022. Originally approved in 2002. Last previous edition approved in 20152016 as
C1531 – 15.C1531 – 16. DOI: 10.1520/C1531-16.10.1520/C1531-22.
2
Graziotti, F., Guerrini, G., Rossi, A., Andreotti, G., and Magenes, G., “Proposal for an Improved Procedure and Interpretation of ASTM C1531 for the In Situ
Determination of Brick-Masonry Shear Strength,” Masonry 2018, ASTM STP 1612, ASTM International, 2018, pp. 13–33, http://dx.doi.org/10.1520/STP161220170181
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C1531 − 22
FIG. 1 Test Setup—Method A
FIG. 2 Test Setup—Method B
FIG. 3 Test Setup—Method C
2

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C1531 − 22
2. Referenced Documents
3
2.1 ASTM Standards:
C1180 Terminology of Mortar and Grout for Unit Masonry
C1196 Test Method for In Situ Compressive Stress Within Solid Unit Masonry Estimated Using Flatjack Measurements
C1197 Test Method for In Situ Measurement of Masonry Deformability Properties Using the Flatjack Method
C1232 Terminology for Masonry
E4 Practices for Force Calibration and Verification of Testing Machines
2.
...