ASTM C1197-22

Standard Test Method for In Situ Measurement of Masonry Deformability Properties Using the Flatjack Method

SIGNIFICANCE AND USE
5.1 Deformation and strength properties are measured only on the masonry between flatjacks. Boundary effects of the collar joint behind the wythe tested and adjacent masonry are neglected. In the case of multi-wythe masonry, deformability is estimated only in the wythe in which the flatjack is inserted. Deformability of other wythes may be different.
SCOPE
1.1 This test method describes an in situ method for determining the deformation properties of existing unreinforced solid-unit masonry. (See Note 1.) This test method concerns the measurement of in-situ masonry deformability properties in existing masonry by use of thin, bladder-like flatjack devices that are installed in cut mortar joints in the masonry wall. This test method provides a relatively non-destructive means of determining masonry properties.
Note 1: Solid-unit masonry is that built with stone, concrete, or clay units whose net area is equal to or greater than 75 % of the gross area.  
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, health, and environmental 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.

General Information

• Status: Published
• Publication Date: 30-Nov-2022
• ICS: 91.060.10 - Walls. Partitions. Facades
• Technical Committee: C15 - Masonry – Manufactured Masonry Units, Mortars and Grouts
• Drafting Committee: C15.04 - Research for Masonry Units and Assemblies

Relations

• Refers: ASTM C1232-23 - Standard Terminology for Masonry
• Effective Date: 15-Dec-2023
• Refers: ASTM C1180-18 - Standard Terminology of Mortar and Grout for Unit Masonry
• Effective Date: 01-Dec-2018
• Refers: ASTM C1232-17 - Standard Terminology for Masonry
• Effective Date: 01-Jun-2017
• Refers: ASTM C1232-15a - Standard Terminology of Masonry
• Effective Date: 01-Sep-2015
• Refers: ASTM C1232-15 - Standard Terminology of Masonry
• Effective Date: 01-Jun-2015
• Refers: ASTM E74-13a - Standard Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines
• Effective Date: 01-May-2013
• Refers: ASTM E74-13 - Standard Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines
• Effective Date: 01-Mar-2013
• Refers: ASTM E74-12 - Standard Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines
• Effective Date: 01-Dec-2012
• Refers: ASTM C1232-12 - Standard Terminology of Masonry
• Effective Date: 01-Jun-2012
• Refers: ASTM C1232-10c - Standard Terminology of Masonry
• Effective Date: 15-Dec-2010
• Refers: ASTM C1180-10 - Standard Terminology of Mortar and Grout for Unit Masonry
• Effective Date: 01-Dec-2010
• Refers: ASTM C1232-10b - Standard Terminology of Masonry
• Effective Date: 15-Jun-2010
• Refers: ASTM C1232-10a - Standard Terminology of Masonry
• Effective Date: 01-May-2010
• Refers: ASTM C1232-10 - Standard Terminology of Masonry
• Effective Date: 01-Jan-2010
• Refers: ASTM C1232-09b - Standard Terminology of Masonry
• Effective Date: 15-Dec-2009

Overview

ASTM C1197-22 outlines the standard test method for in situ measurement of masonry deformability properties using the flatjack method. Developed by ASTM International, this standard is applicable primarily to existing unreinforced solid-unit masonry constructed from stone, concrete, or clay units. The flatjack method is a relatively non-destructive testing approach, allowing engineers to determine the deformation properties of masonry structures directly and efficiently while minimizing damage to the investigated area.

This test method is especially significant for evaluating existing masonry in historical buildings and infrastructure, where traditional destructive testing techniques are not viable or desirable. The method measures deformation properties solely in the section of masonry between flatjacks, providing engineers and asset managers with key insights for structural assessment and conservation planning.

Key Topics

• Flatjack Devices: Thin, bladder-like tools inserted into prepared slots in mortar joints of masonry. Once pressurized with hydraulic fluid, they apply controlled stress to the target masonry section.
• Non-Destructive Evaluation: The flatjack method enables determination of stress-strain properties without significant alteration to the structure, making it highly suitable for heritage and sensitive sites.
• Measurement Procedures: Stress and deformation in the masonry are measured using precise electronic or mechanical gauges. Calibration of flatjacks ensures accurate conversion from internal jack pressure to applied masonry stress.
• Shims and Installation: Proper fitting and use of shims are crucial to ensuring uniform transfer of pressure and reliable results. Grouting is not permitted, as it may alter the masonry’s natural behavior.
• Scope of Measurement: Tests focus only on the wythe or structural layer where the flatjack is inserted. For multi-wythe walls, deformability may differ between layers, but only the tested wythe is characterized by this method.

Applications

The ASTM C1197-22 standard is applicable in a variety of practical scenarios involving masonry assessment:

• Historic Preservation: Evaluate the structural integrity and deformation characteristics of historical buildings to inform restoration or retrofitting decisions.
• Infrastructure Safety: Assess aging bridges, tunnels, and retaining walls composed of solid-unit masonry without causing significant disruption to the structure.
• Engineering Surveys: Provide baseline data on masonry properties for renovation, change of use, load increase, or seismic assessment projects.
• Forensic Engineering: Assist in diagnosing failure mechanisms and the extent of damage after seismic events or other structural incidents.

Typical users include structural engineers, heritage consultants, building surveyors, and infrastructure asset managers seeking accurate, minimally invasive assessment data.

Related Standards

For comprehensive interpretation and use of ASTM C1197-22, the following related ASTM standards are referenced and widely utilized:

• ASTM C1180 - Terminology of Mortar and Grout for Unit Masonry
• ASTM C1232 - Terminology for Masonry
• ASTM E74 - Practices for Calibration and Verification of Force-Measuring Instruments

These standards provide the foundational terminology and calibration procedures necessary for consistent application and reporting in accordance with ASTM C1197-22.

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By using ASTM C1197-22, professionals can carry out reliable, in situ deformation testing of masonry, ensuring safety, durability, and informed decision-making for new and existing masonry structures. This standard supports effective non-destructive testing in line with international best practices and regulatory principles.

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: C1197 −22
Standard Test Method for
In Situ Measurement of Masonry Deformability Properties
Using the Flatjack Method
This standard is issued under the fixed designation C1197; 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* 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method describes an in situ method for
C1180 Terminology of Mortar and Grout for Unit Masonry
determining the deformation properties of existing unrein-
C1232 Terminology for Masonry
forced solid-unit masonry. (See Note 1.) This test method
E74 Practices for Calibration and Verification for Force-
concerns the measurement of in-situ masonry deformability
Measuring Instruments
properties in existing masonry by use of thin, bladder-like
flatjack devices that are installed in cut mortar joints in the
3. Terminology
masonry wall. This test method provides a relatively non-
3.1 Definitions of Terms Specific to This Standard:
destructive means of determining masonry properties.
3.1.1 shim, n—item inserted into a flatjack slot prior to
NOTE 1—Solid-unit masonry is that built with stone, concrete, or clay
testing to minimize the inflation of the test flatjack.
units whose net area is equal to or greater than 75 % of the gross area.
3.1.1.1 Discussion—The use of shims may be necessary
1.2 The text of this standard refers to notes and footnotes
duringtestingtoachieveatightfitoftheflatjackintheslotand
that provide explanatory material. These notes and footnotes
to ensure uniform transfer of pressure (stress) to the masonry
(excluding those in tables and figures) shall not be considered overthecompleteareaoftheflatjack.SeeAnnexA1forfurther
as requirements of the standard. discussion on allowable types of shims.
3.1.2 spacer, n—metal plate used in the calibration process
1.3 The values stated in inch-pound units are to be regarded
to control flatjack thickness.
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only 3.2 For definitions of other terms used in this test method
and are not considered standard. refer to Terminology C1180 for mortar and grout and Termi-
nology C1232 for masonry.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 Two flatjacks inserted into parallel slots, one above the
priate safety, health, and environmental practices and deter-
other, in a solid-unit masonry wall are pressurized thus
mine the applicability of regulatory limitations prior to use.
inducing compressive stress on the masonry between them.
1.5 This international standard was developed in accor-
The installation is shown in Fig. 1. By gradually increasing the
dance with internationally recognized principles on standard-
flatjack pressure and measuring the deformation of the ma-
ization established in the Decision on Principles for the
sonry between the flatjacks, load-deformation (stress-strain)
Development of International Standards, Guides and Recom-
properties may be obtained. Maximum compressive strengths
mendations issued by the World Trade Organization Technical
may be measured in certain cases.
Barriers to Trade (TBT) Committee.
5. Significance and Use
5.1 Deformation and strength properties are measured only
on the masonry between flatjacks. Boundary effects of the
This test method is under the jurisdiction of ASTM Committee C15 on
Manufactured Masonry Units and is the direct responsibility of Subcommittee
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
ɛ1
approved in 1992. Last previous edition approved in 2020 as C1197 – 20 . DOI:
Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1197-22.
the ASTM website.
*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
C1197 − 22
rating hydraulic inlet or outlet ports.
NOTE 3—A maximum operating pressure of 1000 psi (6.9 MPa) is
adequate for most older existing masonry, but flatjacks with higher
operating pressures are available for higher strength masonry, often found
in more recently constructed buildings. Flatjacks manufactured with
flexiblepolymersthathaveoperatingpressurerangesoflessthan1000psi
(6.9 MPa) may be useful for stress measurements in some historic
masonry.
6.1.4 Calibrate all flatjacks as described in Section 8 to
determine their pressure-applied load characteristics.
6.2 Hydraulic System—A hydraulic pump with hydraulic
FIG. 1 Deformation Properties Using Two Flatjacks
hoses is required. Hose connections shall fit the flatjack inlet
port. Measure pressure using gauges calibrated to a traceable
collar joint behind the wythe tested and adjacent masonry are
standard having both an accuracy of 1 % of full hydraulic scale
neglected.Inthecaseofmulti-wythemasonry,deformabilityis
and an appropriate operating range.The hydraulic system shall
estimated only in the wythe in which the flatjack is inserted.
be capable of maintaining constant pressure within 1 % of full
Deformability of other wythes may be different.
scale for at least 5 min.
6. Apparatus 6.3 Displacement Measurement—Measure displacements of
the masonry with electronic instrumentation, for example, a
6.1 Flatjack:
LinearlyVariable DifferentialTransformer (LVDT) mounted to
6.1.1 Aflatjackisathinenvelope-likebladderwithinletand
the surface of the masonry between the flatjacks, or by a
outlet ports which may be pressurized with hydraulic fluid.
mechanical gauge extensometer which measures the distance
Flatjacks may be of any shape in plan, and are designed to be
between fixed gauge points on the masonry as shown in Fig. 1.
compatible with the masonry being tested. For determining
The method or device used to measure deformations shall be
load-deformation properties of masonry, flatjacks are typically
capable of deformation measurements up to ⁄16 in. (5 mm).
rectangular or semi-rectangular as shown in Fig. 2.
Deformation measurements shall have an accuracy of at least
6.1.2 For determination of the state of compressive stress,
60.005 % of gauge length. Record measurements manually at
dimension A should be equal to or greater than the length of a
discrete intervals, or continuously by automatic data recording.
single masonry unit, but not less than 8 in. (200 mm).
Dimension B should be equal to or greater than the thickness
6.4 Attachment of Measurement Devices—Attach brackets
ofonewytheandnotlessthan3in.(75mm).Theradius, R,for
for mounting electrical displacement measuring devices or
circular and semi-rectangular flatjacks shall be equal to the
gauge points to be used with mechanical devices securely to
radius of the circular saw blade used to cut the slot.
thesurfaceofthemasonrytopreventmovementandensurethe
6.1.3 Flatjacksshallbemadeofmetalorothermaterialsuch
required measurement accuracy. Use rigid adhesive for discs
thattheflatjackinaslotinmasonrywillbecapableofapplying
and brackets and cementitious grout for plugs. If gauge points
operating pressures up to the expected maximum flatjack
are used, the gauge points shall have a conical depression at
pressure. See Notes 2 and 3. The flatjack fabricator shall
their center, compatible with the pointed elements of the
provide the manufactured undeformed thickness for each
extensometer. The angles of the depression of the cone and the
flatjack. Fig. 3 shows examples of manufactured undeformed
extensometer points shall be the same.
thicknesses.
7. Preparation of Slots
NOTE 2—Metal flatjacks suitable for this purpose have successfully
been made of type 304 stainless steel sheet of 0.024 (0.6 mm) to 0.048 in.
7.1 Slotsinmasonryarenormallypreparedbyremovingthe
(1.2 mm) in thickness with welded seams along the edges, and incorpo-
mortar from masonry bed joints to avoid disfiguring the
masonry. Remove all mortar in the bed joint, that is, pressure
exertedbyaflatjackshallbedirectlyagainstthesurfacesofthe
masonry units.
7.2 The plan geometry of the slot shall be similar to that of
the flatjack being used. Plan dimensions of the prepared slot
shall not exceed those of the flatjack by more than ⁄2 in.
(12 mm). Slots shall be parallel and aligned vertically, and
shall be separated by not more than 1.5 times the length of the
flatjack.
7.3 Prepare rectangular slots into which rectangular flat-
jacks are to be inserted by drilling adjacent or overlapping
holes(stitchdrilling)andsubsequentlyusingadrill,bar,ortool
to remove mortar and produce a slot of desired dimensions
with smooth upper and lower surfaces. Other tools, such as
FIG. 2 Flatjack Configurations (Plan View) oscillating blade grinders, that can be reliably used to form
C1197 − 22
FIG. 3 Schematic Section Diagram of Two Types of Flatjacks Showing Examples of Manufactured Undeformed Thicknesses
rectangular slots in masonry mortar joints without damaging 8.3 Place a 2 in. (50 mm) thick steel bearing plate on the
the surrounding masonry are also permitted to be used.
lower platen of the compression machine. The bearing plate
shall be of sufficient size to completely cover the flatjack being
7.4 Prepare slots for circular and semi-rectangular flatjacks
calibrated. Place the flatjack on the lower bearing plate such
using circular saws of sufficient radius to provide the depth
that the edge of the flatjack with the inlet/outlet ports is
required (Fig. 2, dimension B). Use carbide or diamond tipped
coincident with the edge of the bearing plate. Place steel
blades to remove all mortar from the slot.
spacers around the other edges of the flatjack. The thickness of
8. Calibration
the spacers shall be 0.015 to 0.050 in. (0.38 to 1.27 mm)
8.1 A flatjack has an inherent stiffness which resists expan- greater than the manufactured undeformed thickness of the
sion when the jack is pressurized. Therefore, the fluid pressure
flatjack (see Fig. 3). Place the upper 2 in. (50 mm) thick
in the flatjack is greater than the stress the flatjack applies to
bearing plate on top of the spacers and flatjack, and align it to
masonry.Aflatjack must be calibrated to provide a conversion
be directly above the lower bearing plate. Position the bearing
factor, K , to relate internal fluid pressure to applied stress.
m plate/flatjack/spacer assembly on the lower platen such that the
centroidoftheareaoftheflatjackiswithin ⁄4in.(6mm)ofthe
8.2 Calibrate flatjacks in a compression machine of at least
axis of thrust of the test machine. The calibration setup is
100 kip (450 KN) capacity which has been calibrated accord-
ing to Practice E74. illustrated in Fig. 4.
FIG. 4 Flatjack Calibration Setup (Elevation View)
C1197 − 22
8.4 Raise or lower the moveable platen such that both 9.5 Insert the flatjack into the slot. Shim, as required, to
platens are in contact with the bearing plates.Apply a pre-load achieve a tight fit and bridge over any interior voids in the
masonry. See AnnexA1 for a description of flatjack shims and
sufficienttoprovidefullcontactbetweenthebearingplatesand
thespacers,equivalentto10psi(0.07MPa)overthegrossarea their use.
o
...

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.
´1
Designation: C1197 − 20 C1197 − 22
Standard Test Method for
In Situ Measurement of Masonry Deformability Properties
Using the Flatjack Method
This standard is issued under the fixed designation C1197; 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.
ε NOTE—Summary of Changes section was editorially updated in January 2021.
1. Scope*
1.1 This test method describes an in situ method for determining the deformation properties of existing unreinforced solid-unit
masonry. (See Note 1.) This test method concerns the measurement of in-situ masonry deformability properties in existing masonry
by use of thin, bladder-like flatjack devices that are installed in cut mortar joints in the masonry wall. This test method provides
a relatively non-destructive means of determining masonry properties.
NOTE 1—Solid-unit masonry is that built with stone, concrete, or clay units whose net area is equal to or greater than 75 % of the gross area.
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, health, and environmental 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.
2. Referenced Documents
2.1 ASTM Standards:
C1180 Terminology of Mortar and Grout for Unit Masonry
C1232 Terminology for Masonry
E74 Practices for Calibration and Verification for Force-Measuring Instruments
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
This test method is under the jurisdiction of ASTM Committee C15 on Manufactured Masonry Units and is the direct responsibility of Subcommittee C15.04 on Research.
Current edition approved Dec. 15, 2020Dec. 1, 2022. Published December 2020December 2022. Originally approved in 1992. Last previous edition approved in 20142020
ɛ1
as C1197 – 14a.C1197 – 20 . DOI: 10.1520/C1197-20E01.10.1520/C1197-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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
C1197 − 22
3.1.1 shim, n—item inserted into a flatjack slot prior to testing to minimize the inflation of the test flatjack.
3.1.1.1 Discussion—
The use of shims may be necessary during testing to achieve a tight fit of the flatjack in the slot and to ensure uniform transfer
of pressure (stress) to the masonry over the complete area of the flatjack. See Annex A1 for further discussion on allowable types
of shims.
3.1.2 spacer, n—metal plate used in the calibration process to control flatjack thickness.
3.2 For definitions of other terms used in this test method refer to Terminology C1180 for mortar and grout and Terminology
C1232 for masonry.
4. Summary of Test Method
4.1 Two flatjacks inserted into parallel slots, one above the other, in a solid-unit masonry wall are pressurized thus inducing
compressive stress on the masonry between them. The installation is shown in Fig. 1. By gradually increasing the flatjack pressure
and measuring the deformation of the masonry between the flatjacks, load-deformation (stress-strain) properties may be obtained.
Maximum compressive strengths may be measured in certain cases.
5. Significance and Use
5.1 Deformation and strength properties are measured only on the masonry between flatjacks. Boundary effects of the collar joint
behind the wythe tested and adjacent masonry are neglected. In the case of multi-wythe masonry, deformability is estimated only
in the wythe in which the flatjack is inserted. Deformability of other wythes may be different.
6. Apparatus
6.1 Flatjack:
6.1.1 A flatjack is a thin envelope-like bladder with inlet and outlet ports which may be pressurized with hydraulic fluid. Flatjacks
may be of any shape in plan, and are designed to be compatible with the masonry being tested. For determining load-deformation
properties of masonry, flatjacks are typically rectangular or semi-rectangular as shown in Fig. 2.
6.1.2 For determination of the state of compressive stress, dimension A should be equal to or greater than the length of a single
masonry unit, but not less than 8 in. (200 mm). Dimension B should be equal to or greater than the thickness of one wythe and
not less than 3 in. (75 mm). The radius, R, for circular and semi-rectangular flatjacks shall be equal to the radius of the circular
saw blade used to cut the slot.
6.1.3 Flatjacks shall be made of metal or other material such that the flatjack in a slot in masonry will be capable of applying
operating pressures up to the expected maximum flatjack pressure. See Notes 2 and 3. The flatjack fabricator shall provide the
manufactured undeformed thickness for each flatjack. Fig. 3 shows examples of manufactured undeformed thicknesses.
NOTE 2—Metal flatjacks suitable for this purpose have successfully been made of type 304 stainless steel sheet of 0.024 (0.6 mm) to 0.048 in. (1.2 mm)
in thickness with welded seams along the edges, and incorporating hydraulic inlet or outlet ports.
NOTE 3—A maximum operating pressure of 1000 psi (6.9 MPa) is adequate for most older existing masonry, but flatjacks with higher operating pressures
FIG. 1 Deformation Properties Using Two Flatjacks
C1197 − 22
FIG. 2 Flatjack Configurations (Plan View)
are available for higher strength masonry, often found in more recently constructed buildings. Flatjacks manufactured with flexible polymers that have
operating pressure ranges of less than 1000 psi (6.9 MPa) may be useful for stress measurements in some historic masonry.
6.1.4 Calibrate all flatjacks as described in Section 8 to determine their pressure-applied load characteristics.
6.2 Hydraulic System—A hydraulic pump with hydraulic hoses is required. Hose connections shall fit the flatjack inlet port.
Measure pressure using gauges calibrated to a traceable standard having both an accuracy of 1 % of full hydraulic scale and an
appropriate operating range. The hydraulic system shall be capable of maintaining constant pressure within 1 % of full scale for
at least 5 min.
6.3 Displacement Measurement—Measure displacements of the masonry with electronic instrumentation, for example, a Linearly
Variable Differential Transformer (LVDT) mounted to the surface of the masonry between the flatjacks, or by a mechanical gauge
extensometer which measures the distance between fixed gauge points on the masonry as shown in Fig. 1. The method or device
used to measure deformations shall be capable of deformation measurements up to ⁄16 in. (5 mm). Deformation measurements
shall have an accuracy of at least 60.005 % of gauge length. Record measurements manually at discrete intervals, or continuously
by automatic data recording.
6.4 Attachment of Measurement Devices—Attach brackets for mounting electrical displacement measuring devices or gauge points
to be used with mechanical devices securely to the surface of the masonry to prevent movement and ensure the required
measurement accuracy. Use rigid adhesive for discs and brackets and cementitious grout for plugs. If gauge points are used, the
gauge points shall have a conical depression at their center, compatible with the pointed elements of the extensometer. The angles
of the depression of the cone and the extensometer points shall be the same.
7. Preparation of Slots
7.1 Slots in masonry are normally prepared by removing the mortar from masonry bed joints to avoid disfiguring the masonry.
Remove all mortar in the bed joint, that is, pressure exerted by a flatjack shall be directly against the surfaces of the masonry units.
7.2 The plan geometry of the slot shall be similar to that of the flatjack being used. Plan dimensions of the prepared slot shall not
exceed those of the flatjack by more than ⁄2 in. (12 mm). Slots shall be parallel and aligned vertically, and shall be separated by
not more than 1.5 times the length of the flatjack.
7.3 Prepare rectangular slots into which rectangular flatjacks are to be inserted by drilling adjacent or overlapping holes (stitch
drilling) and subsequently using a drill, bar, or tool to remove mortar and produce a slot of desired dimensions with smooth upper
and lower surfaces. Other tools, such as oscillating blade grinders, that can be reliably used to form rectangular slots in masonry
mortar joints without damaging the surrounding masonry are also permitted to be used.
7.4 Prepare slots for circular and semi-rectangular flatjacks using circular saws of sufficient radius to provide the depth required
(Fig. 2, dimension B). Use carbide or diamond tipped blades to remove all mortar from the slot.
C1197 − 22
FIG. 3 Schematic Section Diagram of Two Types of Flatjacks Showing Examples of Manufactured Undeformed Thicknesses
8. Calibration
8.1 A flatjack has an inherent stiffness which resists expansion when the jack is pressurized. Therefore, the fluid pressure in the
flatjack is greater than the stress the flatjack applies to masonry. A flatjack must be calibrated to provide a conversion factor, K ,
m
to relate internal fluid pressure to applied stress.
8.2 Calibrate flatjacks in a compression machine of at least 100 kip (450 KN) capacity which has been calibrated according to
Practice E74.
8.3 Place a 2 in. (50 mm) thick steel bearing plate on the lower platen of the compression machine. The bearing plate shall be
of sufficient size to completely cover the flatjack being calibrated. Place the flatjack on the lower bearing plate such that the edge
of the flatjack with the inlet/outlet ports is coincident with the edge of the bearing plate. Place steel spacers around the other edges
of the flatjack. The thickness of the spacers shall be 0.015 to 0.050 in. (0.38 to 1.27 mm) greater than the manufactured undeformed
thickness of the flatjack (see Fig. 3). Place the upper 2 in. (50 mm) thick bearing plate on top of the spacers and flatjack, and align
it to be directly above the lower bearing plate. Position the bearing plate/flatjack/spacer assembly on the lower platen such that
the centroid of the area of the flatjack is within ⁄4 in. (6 mm) of the axis of thrust of the test machine. The calibration setup is
illustrated in Fig. 4.
FIG. 4 Flatjack Calibration Setup (Elevation View)
C1197 − 22
8.4 Raise or lower the moveable platen such that both platens are in contact with the bearing plates. Apply a pre-load sufficient
to provide full contact between the bearing plates and the spacers, equivalent to 10 psi (0.07 MPa) over the gross area of the
flatjack.
8.5 The distance between platens must be held constant during the calibration procedure. Fix the displacement of the test machine
at this point if using a displacement-control machine. If not, attach displacement gauges (mechanical or electrical) such that the
distance between platens established by the procedures of paragraph 8.4 can be held constant when using a force-control test
machine.
8.6 Pressurize and depressurize the flatjack three times over the full operatin
...