ACI 355.4M-11 - Qualification of Post-Installed Adhesive Anchors in Concrete and Commentary (Metric)

ACI 355.4M-11

Qualification of Post-Installed Adhesive Anchors in Concrete (ACI 355.4M-11) An ACI Standard

and Commentary

Reported by ACI Committee 355

First Printing September 2011 American Concrete Institute® Advancing concrete knowledge

Qualification of Post-Installed Adhesive Anchors in Concrete (ACI 355.4M-11) and Commentary Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of ACI. The technical committees responsible for ACI committee reports and standards strive to avoid ambiguities, omissions, and errors in these documents. In spite of these efforts, the users of ACI documents occasionally find information or requirements that may be subject to more than one interpretation or may be incomplete or incorrect. Users who have suggestions for the improvement of ACI documents are requested to contact ACI via the errata website at www.concrete.org/committees/errata.asp. Proper use of this document includes periodically checking for errata for the most up-to-date revisions. ACI committee documents are intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. Individuals who use this publication in any way assume all risk and accept total responsibility for the application and use of this information. All information in this publication is provided “as is” without warranty of any kind, either express or implied, including but not limited to, the implied warranties of merchantability, fitness for a particular purpose or non-infringement. ACI and its members disclaim liability for damages of any kind, including any special, indirect, incidental, or consequential damages, including without limitation, lost revenues or lost profits, which may result from the use of this publication. It is the responsibility of the user of this document to establish health and safety practices appropriate to the specific circumstances involved with its use. ACI does not make any representations with regard to health and safety issues and the use of this document. The user must determine the applicability of all regulatory limitations before applying the document and must comply with all applicable laws and regulations, including but not limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards. Participation by governmental representatives in the work of the American Concrete Institute and in the development of Institute standards does not constitute governmental endorsement of ACI or the standards that it develops. Order information: ACI documents are available in print, by download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI. Most ACI standards and committee reports are gathered together in the annually revised ACI Manual of Concrete Practice (MCP).

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ACI 355.4M-11

A U.S. Customary version of this document (ACI 355.4-11) is available at www.concrete.org

Qualification of Post-Installed Adhesive Anchors in Concrete (ACI 355.4M-11) and Commentary An ACI Standard

Reported by ACI Committee 355 Donald F. Meinheit Chair

Tarek S. Aziz

J. Bret Turley Secretary

Werner A. F. Fuchs *

Richard E. Klingner

Jake Olsen Alan D. Price

Branko Galunic

Anthony J. Lamanna

Peter J. Carrato

Brian C. Gerber

Harry B. Lancelot III

John F. Silva

Harry A. Chambers

Michael Gong

Nam-Ho Lee

Patrick J. E. Sullivan

Ranjit L. Bandyopadhyay

Ronald A. Cook

Herman L. Graves III

Lee W. Mattis

Harry Wiewel

Rolf Eligehausen

Christopher Heinz

Robert R. McGlohn

Richard E. Wollmershauser

Sam S. Eskildsen

Bruce I. Ireland

*Deceased. The committee would like the recognize Christopher LaVine for his significant contributions to this document.

Consulting members Edwin G. Burdette

Paul R. Hollenbach

Robert W. Cannon

Conrad Paulson

Neil M. Hawkins

Dan R. Stoppenhagen Keywords: adhesive anchors; cracked concrete; fasteners; post-installed anchors; qualification procedures; uncracked concrete.

This standard prescribes testing programs and evaluation requirements for post-installed adhesive anchors intended for use in concrete under the design provisions of ACI 318M. Testing and assessment criteria are provided for various conditions of use, including seismic loading; sustained loading; aggressive environments; reduced and elevated temperatures; and for determining whether anchors are acceptable for use in uncracked concrete only, or acceptable for service both in cracked and uncracked concrete. Criteria are provided for establishing the characteristic bond strength, reductions for adverse conditions, and the anchor category and associated job-site quality control requirements. The official version of this ACI document uses inch-pound units. A conversion of an ACI document into SI units is for the convenience of users. Care has been taken to ensure that the conversion is correct; however, ACI does not guarantee its accuracy. Official interpretation of this ACI document shall be based only on the U.S. customary units.

CONTENTS Chapter 1—Introduction and scope, p. 3 1.1—Introduction 1.2—Scope 1.3—Units of measurement Chapter 2—Notation and definitions, p. 5 2.1—Notation 2.2—Defintions Chapter 3—General requirements, p. 11 3.1—Test organization 3.2—Variables and options 3.3—Test requirements 3.4—Assessment for multiple anchor element types for adhesive anchors 3.5—Assessment for alternate drilling methods

ACI Committee Reports, Guides, and Commentaries are intended for guidance in planning, designing, executing, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. The American Concrete Institute disclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom. Reference to this document shall not be made in contract documents. If items found in this document are desired by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.

ACI 355.4M-11 supersedes ACI 355.4-10 (provisional), was adopted July 5, 2011, and published September 2011. Copyright © 2011, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.

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QUALIFICATION OF POST-INSTALLED ADHESIVE ANCHORS IN CONCRETE (ACI 355.4M-11) AND COMMENTARY

Chapter 4—Requirements for test specimens, anchor installation, and testing, p. 17 4.1—Testing by ITEA and manufacturer 4.2—Test samples 4.3—Concrete for test members 4.4—Requirements for test members 4.5—Anchor installation 4.6—Drill bit requirements 4.7—Test methods 4.8—Tests in cracked concrete 4.9—Changes to products Chapter 5—Requirements for anchor identification, p. 24 5.1—Basic requirements 5.2—Verification 5.3—Fingerprinting adhesive materials 5.4—Packaging Chapter 6—Reference tests, p. 24 6.1—Purpose 6.2—Required tests 6.3—Conduct of tests Chapter 7—Reliability tests, p. 25 7.1—Purpose 7.2—Required tests 7.3—Conduct of tests 7.4—Reliability tests 7.5—Sensitivity to hole cleaning—dry concrete 7.6—Sensitivity to hole cleaning—saturated concrete 7.7—Sensitivity to hole cleaning—water-filled hole 7.8—Sensitivity to hole cleaning—submerged concrete 7.9—Sensitivity to mixing effort 7.10—Sensitivity to installation in water-saturated concrete 7.11—Sensitivity to installation in water-filled hole— saturated concrete 7.12—Sensitivity to installation in submerged concrete 7.13—Sensitivity to crack width—low-strength concrete 7.14—Sensitivity to crack width—high-strength concrete 7.15—Sensitivity to crack width cycling 7.16—Sensitivity to freezing and thawing 7.17—Sensitivity to sustained loading at standard and maximum long-term temperature 7.18—Sensitivity to installation direction 7.19—Torque test Chapter 8—Service-condition tests, p. 32 8.1—Purpose 8.2—Required tests 8.3—Conduct of tests 8.4—Tension tests in uncracked and cracked concrete 8.5—Tension tests at elevated temperature 8.6—Tension tests with decreased installation temperature 8.7—Establishment of cure time at standard temperature 8.8—Durability assessment 8.9—Verification of full concrete capacity in a corner 8.10—Determination of minimum spacing and edge distance to preclude splitting

8.11—Tests to determine shear capacity of anchor elements with nonuniform cross section 8.12—Simulated seismic tension tests 8.13—Simulated seismic shear tests Chapter 9—Supplemental tests, p. 38 9.1—Round-robin tests 9.2—Tests to determine minimum member thickness Chapter 10—Assessment of anchors, p. 39 10.1—Analysis of data 10.2—Normalization of anchor capacities for measured concrete bond and steel strengths 10.3—Establishing characteristic values 10.4—Assessment of characteristic tension capacity associated with concrete breakout and pullout 10.5—Assessment of steel tension capacity 10.6—Assessment of steel shear capacity 10.7—Assessment of minimum member thickness 10.8—Assessment of maximum tightening torque 10.9—Assessment of behavior under crack cycling 10.10—Assessment of freezing-and-thawing behavior 10.11—Assessment of sustained load behavior 10.12—Assessment of performance associated with installation direction 10.13—Assessment of performance at elevated temperature 10.14—Assessment of performance with decreased installation temperature 10.15—Assessment for cure time at standard temperature 10.16—Assessment of durability requirement 10.17—Assessment of performance in corner test 10.18—Assessment of performance in minimum spacing and edge distance test 10.19—Assessment of performance under seismic tension 10.20—Assessment of performance under seismic shear 10.21—Establishment of hole cleaning procedures 10.22—Establishment of on-site quality control and installation conditions 10.23—Assessment based on installation and environmental conditions 10.24—Assessment for fire exposure Chapter 11—Data presentation, p. 51 11.1—General requirements 11.2—Contents of evaluation report 11.3—Data presentation Chapter 12—Independent testing and evaluation agency requirements, p. 53 12.1—General requirements 12.2—Certification Chapter 13—Quality control requirements, p. 54 13.1—Quality assurance program 13.2—Quality control manuals 13.3—Special inspection Chapter 14—References, p. 54 14.1—Referenced standards and reports 14.2—Cited references


CHAPTER 1—INTRODUCTION 1.1—Introduction This standard prescribes testing and evaluation requirements for post-installed adhesive anchor systems intended for use in concrete under the provisions of ACI 318M. Criteria are separately prescribed to determine the suitability of adhesive anchors used in uncracked concrete only, or in both cracked and uncracked concrete. Criteria are prescribed to determine the design parameters and performance category for adhesive anchors. Included are assessments of the adhesive anchor system for bond strength, reliability, service conditions, and quality control. Special inspection (13.3) is required during anchor installation as noted in 10.22. Table 1.1 provides an overview of the scope. R1.1 This standard prescribes the testing programs required to qualify post-installed adhesive anchor systems for design in accordance with ACI 318M, Appendix D. Appendix D requires that anchors be tested either for use exclusively in uncracked concrete or for use in cracked and uncracked concrete conditions, whereby it is understood that the presence of cracking may occur at any time over the service life of the anchors. Test and assessment criteria are provided for various conditions, including loads (seismic and sustained), environmental with regard to humidity and temperature, and determination if anchors are acceptable for use in cracked or uncracked concrete. Refer to Cook and Konz (2001) for a review of factors that influence adhesive anchor behavior. Refer to Fuchs et al. (1995) for background on the concrete breakout design model and to Eligehausen et al. (2006) and Zamora et al. (2003) for a discussion of bond models for adhesive and grouted anchors. For a discussion of issues associated with the qualification and design of systems for post-installed reinforcing bars, refer to Spieth et al. (2001). 1.2—Scope This standard applies only to post-installed adhesive anchors as defined herein. R1.2 Adhesive anchors resist tension loads with a combination of adhesion and mechanical bond (micro-interlock). Different anchor designs and adhesive types may exhibit a range of performance characteristics. In particular, the sensitivity of adhesive anchors to variations in installation and service-condition parameters (such as hole cleaning, installation orientation, and cracked concrete characteristics) may vary widely from each system. ACI 318M addresses this situation by matching capacity reduction factors to anchor performance categories that are, in turn, established through a series of reliability tests. 1.2.1 This standard applies to anchors with a diameter da of 6 mm or larger. The drilled hole shall be approximately cylindrical with a diameter do ≤ 1.5da. This standard also applies to anchors with an anchor embedment depth hef not less than four diameters (4da), or 41 mm, and an embedment depth not exceeding 20da. R1.2.1 The minimum diameter of 6 mm is based on practical considerations regarding the limit of structural anchor applications. The upper limit on the ratio of hole

3

Table 1.1—Overview of anchor systems Anchor type

Embedded part

Assessment criteria Uncracked concrete

Threaded rods, deformed Adhesive reinforcing bars, or interanchor nally threaded steel sleeves Cracked and with external deformations uncracked concrete

Table 3.1 Table 3.2 or Table 3.3

diameter to anchor element diameter provides a demarcation between conditions where a single bond strength can be used to evaluate anchor strength and conditions where bond strengths at both the anchor interface and concrete interface must be determined to evaluate anchor strength. In addition, the value of 1.5da is based on consideration of typical practice whereby most organic adhesives are used with thin bond lines to limit both adhesive shrinkage and creep of the anchor when under load. The design method deemed to satisfy the anchor design requirements of ACI 318M, Appendix D, is based on an analysis of an anchor database with a maximum diameter of 50.8 mm. While ACI 355.4M gives no limitations on maximum anchor diameter, for anchors beyond this dimension, the testing authority should decide if the tests described in this standard are applicable or if alternative tests and analyses are more appropriate. It may also be desirable to reconsider those tests where only small, medium, and large diameters are tested when the upper diameter is much larger than 38 mm. A limitation on the minimum embedment length of adhesive anchors is necessary to ensure conformance with the design method deemed to satisfy the anchor design requirements of ACI 318M, Appendix D. 1.2.2 The minimum member thickness shall not be less than the value given by Eq. (10-21). Values of Δh in Eq. (10-21) shall be permitted if they are verified by tests according to Table 3.1, Test no. 14, and Table 3.2, Test no. 20, or Table 3.3, Test no. 15. 1.2.3 This standard does not address the following systems and use conditions: 1. Bulk adhesives mixed in open containers without automatically controlled metering and mixing of adhesive components. 2. Adhesives to adhere structural elements to concrete surfaces outside of a drilled hole. 3. Adhesive anchors in aggressive environments not specifically considered in this standard. 4. Adhesive anchors to resist fatigue or shock loading. R1.2.3 Correct proportioning (metering) and mixing of adhesive components is critical to their performance. Bulk mixing and delivery of adhesives (for example, those with paddle mixers in buckets), while appropriate for some applications, may not provide anchor performance consistent with the assumptions of this standard. These systems are not considered to provide controlled metering of adhesive components. Bulk dispensing equipment that provides automatic metering and mixing of the adhesive components is included; however, ongoing monitoring is required to check that the equipment is operating within tolerances in accordance with the Manufacturer’s Printed Installation

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Fig. R1.1—Examples of post-installed reinforcing bars proportioned with anchor theory and with concepts of reinforcement development and splicing. Instructions (MPII), particularly with respect to mixture ratios, leak tightness, and dwell time. This standard is not appropriate for assessing the use of adhesives to adhere structural elements to the concrete surface. Examples include bonded steel plates or external carbon fiber reinforcement. Other standards exist for these purposes. This standard includes tests to assess the sensitivity of adhesive anchor systems to a limited range of aggressive environments, including moisture, highly alkaline fluids, and sulfur dioxide. While it is believed that these exposure environments envelop a range of possible exposures, specific environments (for example, radiation exposure and chemical production environments) may require unique assessment. Due to the variety of possible loading conditions associated with fatigue and shock loading, this standard does not include tests for these loading variants. Fatigue and shock loading may result in reductions in bond strength, steel strength, and concrete strength, and these effects are not addressed by this standard. Caution should be exercised in the determination of whether cyclic loading should be explicitly considered. These conditions may be evaluated separately for specific systems using generally accepted principles. Fatigue is generally less of a problem for the adhesive than for the anchor element; provisions of preload in the anchor to reduce the level of stress fluctuation in the anchor element is only effective if sufficient unbonded length is provided to ensure a reasonable degree of elastic stretch. 1.2.4 Adhesive anchors shall be evaluated for sustained loading with the provisions of this standard. Qualification of

adhesive anchors exclusively for short-term loads is not permitted by this standard. R1.2.4 While it is permissible to use adhesive anchors to resist short-term loads such as those from wind or earthquake, the sustained load tests and corresponding assessment described herein are not optional. All anchors qualified in accordance with ACI 355.4M are suitable for sustained loads within the use parameters established in the assessment (7.17 and 10.4.7). 1.2.5 Adhesive anchor systems shall exhibit characteristic bond strengths as determined in accordance with Eq. (10-12) equal to or exceeding the minimum permissible bond strength τk,min. Adhesive anchor systems that do not exhibit characteristic bond strengths equal to or exceeding the minimum permissible bond strength in accordance with 10.2, shall not be qualified according to this standard. R1.2.5 ACI 318M, Appendix D, provides default bond stress values for specific constellations of use parameters that may be used in place of values from an evaluation report in accordance with this standard. Because the default values are independent of the adhesive anchor system selected, they represent minimum values for the assessment of any adhesive anchor system under this standard. The minimum values and corresponding use parameters are given in Table 10.2. 1.2.6 In general, ACI 355.4M is intended to address the assessment of adhesive anchors for cases where anchor design theory applies. It is not intended to address the assessment or design of post-installed reinforcing bars proportioned according to the concepts of development and splicing of reinforcement.


R1.2.6 This standard is intended to provide parameters for the design of adhesive anchors in conjunction with the provisions of ACI 318M, Appendix D. Those provisions are derived from the principles of anchor theory, whereby anchor forces are transferred to the concrete in a manner that generally precludes splitting of the concrete and where spacing, edge distance, and member thickness are explicitly considered in the evaluation of the concrete breakout capacity (Fig. R1.1(a)). It is not intended to address the assessment or design of post-installed reinforcing bars proportioned according to the concepts of development and splicing of reinforcement (Fig. R1.1(b)). While the provisions of Chapter 12 of ACI 318M may be used to establish embedment lengths for post-installed reinforcing bars in such cases, the ability of an adhesive anchor system to transfer loads to adjacent embedded bars, particularly where longer splice lengths are required, should be verified by appropriate testing. Testing for the splice length is outside the scope of this standard. 1.3—Units of measurement Values in this specification are stated in SI units. A companion specification in inch-pound units is also available. CHAPTER 2—NOTATION AND DEFINITIONS 2.1— Notation Ase,N = effective cross-sectional area of anchor in tension, mm2 Ase,V = effective cross-sectional area of anchor in shear, mm2 cac = critical edge distance required to develop the basic concrete breakout strength of anchor in uncracked concrete without supplementary reinforcement to control splitting, mm cmin = minimum anchor edge distance required to prevent splitting during anchor installation, mm, see 8.10 = nominal outside diameter of post-installed da anchor, mm, see Fig. 2.1 de = nominal diameter of bolt or threaded anchor element in a sleeved insert, mm, see Fig. 2.1

do

=

Fi

=

Fk

=

Ftest,i

=

Ftest,i,fc

=

Fy

=

fc′ fc,i

= =

fc,test,x

=

ft

=

futa fut,test

= =

fya h

= =

hef

=

hmin

=

hsl

=

K

=

Fig. 2.1—Adhesive anchor dimensional parameters.

5

nominal diameter of drilled hole in the concrete, mm, see 2.1 test result normalized to considered concrete strength i, N characteristic capacity for a test series, calculated according to 10.3, N mean anchor capacity as determined from test series i, N mean capacity for test series i, normalized to concrete strength fc , in accordance with 10.2, N tension force corresponding to bolt yield in accordance with Eq. (10-22), N specified strength of concrete, MPa mean concrete compressive strength measured with standard cylinders for concrete of batch i, MPa mean concrete compressive strength measured with standard cylinders of the test members used for test series x, MPa mean ultimate tensile strength of anchor steel as determined by test, MPa specified tensile strength of anchor steel, MPa specified ultimate tensile strength of steel anchor elements used in seismic tests, MPa specified yield strength of anchor steel, MPa thickness of test member in which an anchor is installed, measured perpendicular to the concrete surface, mm, see Fig. 2.1 effective embedment depth, measured from the concrete surface to the deepest point at which bond to the concrete is established, mm, see Fig. 2.1 minimum member thickness specified by the anchor manufacturer and verified in accordance with 9.2 and 10.7, mm slice thickness as measured immediately prior to punch testing in accordance with 8.8, mm tolerance factor corresponding to a 5 percent probability of nonexceedence with a confidence of 90 percent, derived from a noncentral tdistribution for which the population standard deviation is unknown

6


k

=

kcr

=

kf km

= =

kuncr

=

lside

=

N95%

=

N95%,slip,d =

minNadh,i = Nadh

=

Nadh,i,j

=

Ncure

=

Ncure+24h =

effectiveness factor, whose value depends on the type of anchor effectiveness factor for anchors tested in cracked concrete friction factor of threads mean coefficient for the concrete breakout tension effectiveness factor for anchors tested in uncracked concrete dimension of the side of a cube or diameter of a cylinder for conducting a freezing-andthawing test, mm 95 percent fractile at 90 percent confidence of the induced tension force corresponding to 1.3Tinst , N 95 percent fractile at 90 percent confidence of the force corresponding to loss of adhesion between the anchor element and the adhesive for anchor diameter d, N minimum value of tension load corresponding to loss of adhesion in test series i, N tension load corresponding to loss of adhesion between the adhesive and the concrete, N tension load corresponding to loss of adhesion in reliability test series i, test j, N

mean tension capacity corresponding to the manufacturer’s published minimum cure time plus 24 hours, N = maximum tension load to be applied in the Neq simulated seismic tension test, N Neq,reduced = reduced maximum tension load at which the anchor successfully completes the simulated seismic tension test, N, see 10.19.1.2 Ni = intermediate tension load to be applied in the simulated seismic tension test, N Ni,reduced = reduced intermediate tension load at which the anchor successfully completes the simulated seismic tension test, N, see 10.19.1.2 Nk = characteristic tension capacity of an anchor, 5 percent fractile of test results, as determined in accordance with 10.3, N = characteristic tension capacity corresponding Nk,cure to the manufacturer’s published minimum cure time, N Nk,cure+24h = characteristic tension capacity corresponding to the manufacturer’s published minimum cure time plus 24 hours, N Nk,i = characteristic tension capacity of an anchor in test member i or concrete batch i, N Nk,lt = characteristic tension capacity at long-term elevated temperature, N Nk,o,i = characteristic tension capacity of an anchor in reference test series i, N Nk,p,nom,cr = characteristic tension capacity corresponding to service-condition tests in low- and highstrength cracked concrete, N

Nk,p,nom,uncr= characteristic tension capacity corresponding to service-condition tests in low- and highstrength uncracked concrete, N Nk,r,i = characteristic tension capacity of an anchor in reliability test series i, N Nk,st = characteristic tension capacity at short-term elevated temperature, N Nlt = mean tension capacity of an anchor at longterm elevated temperature, N Nm = minimum tension load to be applied in the simulated seismic tension test, N Nm,reduced = reduced minimum tension load at which the anchor successfully completes the simulated seismic tension test, N, see 10.19.1.2 No = mean tension capacity of an anchor, N No,i = mean tension capacity of an anchor in reference test series i, N No,i,confined= mean tension capacity of anchor in confined reference tests i, N Norigin = tension load corresponding to origin of loaddisplacement curve, N Np = characteristic tension pullout capacity of an anchor, 5 percent fractile of test results, as determined in accordance with 10.3, N Nr,i = mean tension capacity of an anchor in reliability test series i, N Ns = characteristic tension steel capacity of an anchor as determined in accordance with 10.3, N Nst = mean tension capacity at short-term elevated temperature, N = sustained tension load applied during Nsust,ft freezing-and-thawing cycles, N Nsust,lt = sustained tension load applied at long-term test temperature, N Nu = peak tension load measured in a tension test, N Nu,i = peak tension load measured in a tension test in test series i or concrete batch i, N Nu,i = mean ultimate tension load measured in a tension test in test series i or concrete batch i, N = peak tension load measured in a tension test Nu,i,fc conducted in test series i or concrete batch i, normalized to concrete strength fc , N = peak tension load measured in a tension test Nu,i,j in test series or concrete batch i, test j, N Nw = tension load applied to anchor during crack width cycling, N n = number of replicates in a test series, number of anchors in an anchor group, and exponent for determining relationship of bond stress as a function of concrete compressive strength smin = minimum anchor spacing as required to prevent splitting during anchor installation or tension loading, mm, see 8.10 Tinst = specified tightening torque for setting or prestressing of an anchor, according to the MPII, N-m tservice = intended anchor service life, in hours


Veq

=

Veq,reduced =

Vi

=

Vi,reduced =

Vm

=

Vm,reduced =

Vo,i

=

Vs

=

VS,seis

=

α

=

αalk

=

αadh

=

αcat3

=

αconc

=

αCOV

=

αdur

=

αlt

=

αN,seis

=

αreq

=

αreq,cat3 = αsetup

=

αst

=

αsulf

=

αV,seis

=

αρ

=

αρ,sust

=

maximum shear load to be applied in the simulated seismic shear test, N reduced maximum shear load at which the anchor successfully completes the simulated seismic shear test, N, see 10.20.1.2 intermediate shear load to be applied in the simulated seismic shear test, N reduced intermediate shear load at which the anchor successfully completes the simulated seismic shear test, N, see 10.20.1.2 minimum shear load to be applied in the simulated seismic shear test, N reduced minimum shear load at which the anchor successfully completes the simulated seismic shear test, N, see 10.20.1.2 mean shear capacity of an anchor in reference test series i, N characteristic shear capacity corresponding to steel failure, N seismic shear capacity as governed by steel failure, N ratio of reliability to reference tension test results calculated in accordance with 10.4.3 reduction factor for alkalinity in accordance with 10.16 ratio of the load at loss of adhesion to the peak load calculated in accordance with 10.4.4 additional reduction factor for Anchor Category 3 in accordance with 10.4.6.2 adjustment factor for regional variations in concrete in accordance with 10.4.1.2 reduction factor for larger coefficients of variation in accordance with 10.4.2 reduction factor for durability tests in accordance with 10.16 reduction factor for maximum long-term temperature in accordance with 10.13.1 reduction factor for seismic tension loading in accordance with 10.19 threshold value of α given in Table 3.1, 3.2, or 3.3 αreqfor Anchor Category 3 for corresponding reliability test in accordance with Table 10.5 or 10.6 reduction factor for service-condition tests performed as confined tests in accordance with 10.4.5.1 reduction factor for maximum short-term temperature in accordance with 10.13.2 reduction factor for sulfur in accordance with 10.16 reduction factor for seismic shear loading in accordance with 10.20 reduction factor for reliability tests in accordance with 10.4.7.1 reduction factor for sustained load reliability test in accordance with 10.4.7.2

β

=

7

reduction factor evaluated as the minimum of α/αreq and αadh for reliability tests and service-condition tests listed in Tables 10.3 and 10.4 in accordance with Eq. (10-12) Δ = anchor displacement as measured in a test, mm Δ0.3 = displacement at N = 0.3Nu, mm = mean displacement corresponding to loss of Δlim adhesion load Nadh, mm Δorigin = displacement at origin of load displacement curve, mm Δservice = extrapolated estimate of the total displacement over the anchor intended service life, mm Δservice = mean value of the extrapolated estimate of the total displacement over the anchor intended service life, mm = initial displacement under sustained load, mm Δt=0 Δh = concrete thickness beyond hef , mm, see 2.1 Δ(t) = displacement at time t under sustained load, mm Δw = required change in crack width, in addition to the initial hairline crack width as measured after anchor installation, mm φ = strength reduction factor for concrete failure and steel failure modes corresponding to the anchor category established in accordance with 10.4.6 and 10.5, respectively νtest,x = sample coefficient of variation for test series x equal to the sample standard deviation divided by the mean, percent τdur,i = minimum of mean bond stress corresponding to durability tests with test member i or concrete batch i stored in different media according to 8.8.3, MPa = calculated bond stress corresponding to peak τi load in a tension test, MPa τi = mean bond stress corresponding to test series i or concrete batch i, MPa τk,(cr,uncr) = characteristic bond stress in cracked or uncracked concrete, respectively, adjusted for variations in concrete batches and reduced in accordance with 10.4.5.3.2, MPa = characteristic bond stress corresponding to τk,i tension tests in test member i or concrete batch i, MPa τk,min = minimum permissible bond strength in accordance with 1.7, MPa τk,o,i = characteristic bond stress corresponding to reference tension tests in test member i or concrete batch i, MPa τk,seis,(cr,uncr)= seismic tension bond resistance calculated in accordance with 10.4.5.5, MPa τo,i = bond stress corresponding to a reference tension test in test member i or concrete batch i, MPa τref,fc = mean bond stress corresponding to roundrobin tests, MPa τu = calculated bond stress adjusted for variations in concrete batches, MPa τu = mean bond stress, MPa

8

τu,i


=

mean bond stress from reliability test series in concrete batch or test member i, MPa

2.2—Definitions adhesive—any adhesive comprised of chemical components that cure when blended together. Adhesives are formulated from organic polymers, or a combination of organic polymers and inorganic materials. Organic polymers used in adhesives can include, but are not limited to, epoxies, polyurethanes, polyesters, methyl methacrylates, and vinyl esters. adhesive—it is not intended that adhesives be restricted to those listed in this standard and the listing of a specific adhesive does not imply any preference. The suitability of a specific adhesive for anchoring applications may also be dictated by health and safety requirements as contained, for example, in the product Material Safety Data Sheet (MSDS). This standard does not address issues such as adhesive toxicity, safe disposal of adhesive compounds, or conformance with sustainable building requirements as applicable. adhesive anchor—a post-installed anchor, inserted into hardened concrete with an anchor hole diameter not greater than 1.5 times the anchor diameter, that transfers loads to the concrete by bond between the anchor and the adhesive and bond between the adhesive and the concrete. adhesive anchor—evaluation of the tension resistance of grouted anchors installed in hole diameters greater than 1.5da requires separate consideration of bond stresses developed along the anchor element/grout interface, as well as between the grout and the concrete. Because these anchors may demonstrate tension behavior that does not conform to the design method deemed to satisfy the anchor design requirements of ACI 318M, Appendix D, they are not considered in this standard. adhesive anchor system—for the purposes of this standard, the adhesive anchor system is comprised of the following components: • Anchor • Proprietary adhesive compounds in combination with a mixing and delivery system where different mixing and delivery systems are provided for the same adhesive anchor system, it shall be verified through testing that the mixing and delivery systems yield equivalent performance of the installed anchor • Accessories for cleaning the drilled hole, including brushes, air nozzles, and other items needed to complete the cleaning process • Printed instructions for the adhesive anchor installation including hole preparation, injection, and cure for all environmental conditions permitted in the qualification. adhesive anchor system—this standard addresses the testing and assessment of adhesive anchor systems, whereby all components of the system (for example, the anchor itself and all accessories and instructions necessary for the installation in the drilled hole) are included in the assessment. Instructions for use as provided by the manufacturer, should include specific instructions for all conditions of installation to be included in the evaluation, including installation in

water-saturated concrete, water-filled holes, overhead installation, and other adverse installation conditions. aggressive environment—any anchor environmental exposure that may be characterized as equivalent to that produced by exposure of the adhesive compound to an alkaline environment and a high sulfur dioxide concentration. aggressive environment —testing of adhesive compounds as used in adhesive anchor applications to resist chemical exposure is limited in this standard to alkalinity, which is mandatory, and sulfur dioxide, which is optional. As both of these tests involve exposure to water, evaluation of the adhesive for susceptibility to hydrolyzation is included as well. ACI Committee 355 believes alkalinity is the most common aggressive chemical exposure condition. This standard considers the effects of alkalinity and sulfur dioxide separately, and the αdur factor is taken as the condition representing the greatest reduction in strength. anchor—a steel element post-installed into a hardened concrete member and used to transmit applied loads. Steel elements for adhesive anchors may include threaded rods, deformed reinforcing bars, or internally threaded steel sleeves with external deformations. anchor—the term “anchor,” as used herein, refers to the steel component bonded to the concrete with adhesive. The bond model used in ACI 318M is appropriate for steels only because the use of non-steel elements may influence the bond stress distribution and may involve failure modes not considered in the model. anchor category—an assigned rating that corresponds to a specific strength reduction factor φ for concrete failure modes associated with anchors in tension. The anchor category is established by performance of the anchor in reliability tests. anchor category—assignment of the anchor category is intended to represent sensitivity of the anchor system (for example, variations in installation conditions). It is used to determine the strength reduction factor in ACI 318M, Appendix D. anchor installation—unless otherwise noted, the process defined by the MPII for the subject anchor. anchor installation—anchor installation parameters shall include, but are not limited to, ambient air and concrete temperature at the time of installation, concrete type and strength, presence of moisture or water in the drilled hole at installation time, hole drilling method, hole diameter, hole cleaning and preparation requirements, adhesive material conditioning, mixing and placement, anchor element installation and retention, gel and cure time restrictions, and installer safety requirements. It is assumed that all aspects of anchor installation are described in the MPII for all installation conditions, including installation direction and concrete temperature. bulk adhesives—two-component adhesives supplied in industrial quantities in either barrels or 4 to 19 L cans. They are delivered with a bulk dispensing machine whereby metering and mixing of the components are automatically controlled during dispensing through a metering manifold and disposable mixing nozzle.


bulk adhesives—the use of bulk adhesive in conjunction with automatic mixing and metering equipment that ensures the correct proportioning and mixing of the adhesive components is permitted in conjunction with the standard. Such equipment is considered part of the adhesive anchor system. The use of bulk adhesive components metered, mixed, and delivered manually (that is, poured) is not addressed by this standard. capsule anchor systems—adhesives for anchor applications packaged in glass or foil capsules. Capsule diameter corresponds approximately to nominal anchor diameter. The quantity of resin, hardener, and aggregate component in each capsule is suitable for a single anchor application. Component mixing is achieved during anchor installation. The capsule is fragmented and becomes part of the hardened resin matrix. capsule anchor systems—unlike cartridge and bulk adhesive anchor systems, capsule anchor systems are designed to deliver a finite quantity of adhesive into the drilled hole. Their use, therefore, is generally limited to discrete embedment depths for each anchor diameter corresponding to complete filling of the annular gap with cured adhesive. For deeper embedments, use of multiple capsules may be specified by the manufacturer. The drilling action during setting of spin-set capsule anchors is critical to the correct mixing and curing of adhesive. Unlike cartridge systems, the characteristics of the tool used for setting of the anchor, such as horsepower, torque, and rpm, is an integral part of the anchor system. Capsule anchors that are set with hammering action only, hammer-set may have other parameters that are critical in this regard. cartridge systems—two-component adhesives for anchor applications packaged in cartridges for use with either manuallyor power-driven dispensers. Metering and mixing of the components is automatically controlled as the adhesive is dispensed through a manifold and disposable mixing nozzle. cartridge systems—cartridge systems may employ different types of injection equipment depending on, for example, the anchor size and hole depth. Each injection system used with the adhesive anchor system should be evaluated as part of the anchor qualification in accordance with this standard. characteristic value—the 5 percent fractile, that is, value with a 95 percent probability of being exceeded with a confidence of 90 percent. Refer to five percent fractile. characteristic value—the characteristic value is used for design in ACI 318M, Appendix D. The characteristic value is less than the average by a percentage of the average and based on the number of tests conducted, the confidence level that the code writing body elects to use, and an accepted failure rate. The characteristic value or 5 percent fractile has been selected for anchorage design. closed crack—condition of a crack in an unloaded test member. Refer to hairline crack. closed crack—crack closure in cracked concrete test members is facilitated by tension forces in the test member of the longitudinal reinforcing steel. Following unloading of the test member, a residual crack width approximately 0.05 mm will typically remain. The residual crack width

9

associated with a closed crack may be influenced by the presence of anchors installed in the crack path and by the crack width cycling history of the test member. concrete batch—a mixture of specific amounts of cement, aggregate, water, and admixtures prepared and placed at a specific time and cured in a specific manner. concrete batch—a concrete batch is one mixture of concrete from which test members are made. It represents a single mixture so that variations from different batches can be eliminated in the testing. Batch control requirements are provided in 4.4. concrete breakout failure—failure of the anchor in an unconfined tension test, characterized by the formation of a conical fracture surface originating at or near the embedded end of the anchor element and projecting to the surface of the concrete test member. concrete breakout failure—the concrete breakout surface is associated with concrete breakout failure mode. The design method deemed to satisfy the anchor design requirements of ACI 318M, Appendix D, idealizes the shape and dimensions of the concrete breakout surface to establish spacing and edge distance effects associated with concrete breakout, edge breakout, and pryout failure modes. Adhesive anchors may exhibit concrete breakout failure before attainment of the maximum bond stress achievable for the adhesive in question. Sometimes concrete breakout surface formation is observable in the test and in other cases it may not reach the concrete surface before the associated fracture process in the concrete precipitates a bond failure. Care should be taken in the characterization of failure modes based on test observations. cracked concrete—for the purposes of this standard, a test member with a uniform crack width over the depth of the concrete test member. cracked concrete—for purposes of this test program, cracked concrete refers to an idealized crack with parallel walls, and not the wedge-shaped crack opening expected in bending. Parallel crack openings are used because they represent the most critical condition for the anchor response to loading. cure time—the elapsed time from after mixing the adhesive material components until the adhesive material in the drilled hole achieves mechanical properties that correspond to those established with the test conducts described in this standard and are consistent with final design. cure time—cure time is influenced by concrete and ambient temperature. For adhesive placement in deep embedments and/or large-diameter holes, rapid cure brought on by high concrete temperatures may result in voids, incomplete embedment of the anchor, and loss of bond. Retarded cure associated with low temperatures may likewise result in loss of adhesive in nondownhole applications. The manufacturer should specify proper procedures for permissible installation temperatures as required ensuring correct anchor placement and attainment of maximum bond strength. Refer to gel time.

10


dry concrete—concrete that, at the time of adhesive anchor installation, is 21 days and older and has not been exposed to water for the preceding 14 days. dry concrete—the term “dry concrete” as used herein is relevant to the establishment of anchor performance in connection with reliability tests. elevated concrete temperature—interior temperature of concrete within vicinity of anchor location. Short-term elevated concrete temperatures occur over brief intervals, for example, as a result of diurnal cycling. Long-term concrete temperatures are roughly constant over significant periods of time. elevated concrete temperature—elevated concrete temperatures arise from a number of factors, including sun exposure, proximity to operating machinery, or containment of liquids or gasses at elevated temperature. To establish design bond strengths, two classes of elevated concrete temperature are identified: 1. Where elevated concrete temperatures are transient or part of a regular cycle of heating and cooling, such as day-night temperature rise and fall, they are considered short-term elevated temperatures for the purposes of this standard; and 2. Where concrete temperatures may remain elevated over weeks or months, they should be considered longterm elevated temperatures. Concrete temperature as an installation parameter is addressed separately in 8.6 and 8.7. five percent fractile—a value corresponding to a 5 percent probability of nonexceedence with a confidence of 90 percent based on a Gaussian distribution for which the population standard deviation is unknown. Refer to characteristic value. five percent fractile—this section intentionally left blank. gel time—the elapsed time after mixing adhesive material components to onset of significant chemical reaction as characterized by an increase in viscosity. gel time—mechanical disturbance of the chemical reaction after the gel time has elapsed and before the attainment of full cure as defined by the cure time is likely to result in impairment of adhesive material mechanical properties. hairline crack—a crack in an unloaded test member resulting from tension loading of the member. hairline crack—hairline cracks in test members used for anchor testing in cracks are typically 0.05 mm. The residual crack width associated with a hairline crack may be influenced by the presence of anchors installed in the crack path and the crack width cycling history of the test member. Independent Testing and Evaluation Agency (ITEA)— a laboratory accredited in conformance with requirements in Chapter 12 having responsibility for testing and assessment of an anchor product in accordance with the criteria in this standard. Independent Testing and Evaluation Agency (ITEA)— laboratories engaged in testing and evaluation of adhesive anchor systems must be familiar with the test procedures and reference standards described in this standard as applicable and have demonstrated conformance with the procedures and policies set forth in ISO 17020 and ISO 17025. The

testing agency and evaluation agency may be separate organizations. load at loss of adhesion—load corresponding to the loss of adhesion between adhesive and concrete in a tension test (10.4.4.1). load at loss of adhesion—loss of adhesion is typically identified as an abrupt change in the load-slip response of an adhesive anchor in a tension test and marks the transition from resistance associated primarily with adhesion, or chemical bond, to frictional resistance or micro-keying. Manufacturer’s Printed Installation Instructions (MPII)—published instructions for correct anchor installation under all covered installation conditions as supplied in product packaging by the manufacturer of the adhesive anchor system. The MPII shall include information on storage conditions, shelf life, and all restrictions on installation conditions (10.22.1). Manufacturer’s Printed Installation Instructions (MPII)—for the purposes of this standard, the MPII is the sole source of instruction for the installation of the adhesive anchor system. It must be included in packaging for the adhesive anchor system and cannot be supplied in the form of supplementary documentation or verbal instruction. The format, text, pictograms, photos, or other graphic devices used to convey the installation procedures should be legible, self-explanatory, and understandable for persons having a secondary school or higher education level. It is the responsibility of the ITEA to evaluate the MPII and assess its suitability prior to beginning the test program. primary testing laboratory—ITEA with primary responsibility for testing and assessment of an anchor product in accordance with this standard. primary testing laboratory—while it is permissible for multiple ITEAs to be engaged in the assessment of a single adhesive anchor system, one laboratory is responsible for the coordination and overall assessment of the system. pullout failure—a failure mode characterized by the withdrawal of the anchor element from the concrete without rupture of the embedded part—for example, the threaded rod or reinforcing bar—and without formation of a full-depth conical breakout surface. The formation of limited-depth conical breakout surfaces shall also be considered as pullout failures. pullout failure—visual assessment of pullout failure is difficult in many cases. This standard compares the predicted concrete breakout strength with the maximum bond strength, as based on the characteristic limiting bond stress, to determine pullout failure. saturated concrete—concrete that, at the time of adhesive anchor installation, has been exposed to water over a sufficient length of time to have the maximum possible amount of absorbed water into the concrete pore structure to a depth equal to the anchor embedment depth. saturated concrete—the term “saturated concrete” as used herein is relevant to the establishment of anchor performance in connection with reliability tests. shelf life—recommended time that adhesive materials may be stored before degradation may begin. Shelf life shall


be determined by appropriate testing, indicated on the adhesive anchor system packaging, with required storage conditions described in the MPII. shelf life—influenced by storage conditions. The MPII should clearly state the storage requirements associated with predicted shelf life for the adhesive. small, intermediate, and large diameters—the smallest, intermediate, and largest diameters are to be determined from the manufacturer’s published or production anchor diameters of the tested anchor system. The intermediate diameter shall be taken as least 3 mm larger than the smallest diameter and the diameter most closely representing the arithmetic mean of the smallest and largest diameters. small, intermediate, and large diameters—this section intentionally left blank. splitting failure—a concrete failure mode characterized by the formation of a planar crack in the concrete parallel to and extending through the axis of the anchor or anchors. standard temperature—23°C ± 4°C. statistically equivalent—two groups of test results shall be considered statistically equivalent if there are no significant differences between the means and the standard deviations of the two groups. Such statistical equivalence shall be demonstrated using a one-sided Student’s t-Test at a confidence level of 90 percent. steel failure—a failure mode characterized by fracture of the anchor element. test member—a concrete element in which anchors are installed and tested. test member—this section intentionally left blank. test series—a group of identical anchors tested under identical conditions. Identical conditions include anchor diameter, length, embedment, spacing, edge distance, hole diameter and depth, concrete density/weight, test member thickness, and concrete compressive strength. uncracked concrete—for purposes of this standard, a concrete test member that is uncracked at the beginning of the test. CHAPTER 3—GENERAL REQUIREMENTS 3.1—Test organization 3.1.1 Qualification of an anchor system in accordance with ACI 355.4M evaluates the anchor system under four types of tests: 1. Identification tests to evaluate anchor compliance with manufacturer’s specifications (Chapter 5) 2. Reference tests to obtain baseline values for the evaluation of reliability and service-condition test results (Chapter 6) 3. Reliability tests to assess anchor sensitivity to adverse installation conditions and long-term loading (Chapter 7) 4. Service-condition tests to establish anchor performance under expected service conditions (Chapter 8) R3.1.1 The classification of test types in this standard is identical to that established in ACI 355.2 (ACI Committee 355 2007). 3.1.2 In addition, the following supplemental service-condition tests (3.1.2.1 through 3.1.2.3) are included (Chapter 9).

11

3.1.2.1 Mandatory round-robin tests for adhesive anchors shall be performed to establish the effects of regional variations in concrete on anchor behavior (9.1). R3.1.2.1 Round-robin tests were introduced in ACI 355.4M to avoid undue influence of regional concrete composition on anchor tension strength. Round-robin tests followed extensive, but inconclusive, investigations to determine the precise nature of concrete composition influence on adhesive anchor performance. Theories regarding this effect include variations in concrete porosity, as reflected in the concrete density, and aggregate hardness. Limited experimental evidence indicates these effects may lessen as the concrete age increases. Round-robin tests are performed in regional concretes to establish and compare a nominal bond strength for generally expected anchor performance against the tested anchor bond strength. Based on round-robin tests (establishing a bond strength above or below the ITEA value) the reported bond strength is adjusted up or down. Refer to 9.1 and 10.4.1 for further methodology. 3.1.2.2 Supplemental assessment tests for multiple anchor element types (refer to 3.4). 3.1.2.3 Supplemental assessment tests for alternate drilling methods (refer to 3.5). 3.2—Variables and options R3.2 Optional tests are specified in ACI 355.4M. Omission of optional tests will result in limitations being placed on use of the adhesive anchor system. 3.2.1 The assessment of a given anchor system in accordance with ACI 355.4M includes consideration of the following system variables and optional installation and use conditions: 1. Presence of water during anchor installation— Installation procedures, including hole cleaning procedures, are as specified in the MPII. Hole cleaning procedures typically include vacuuming, evacuation with forced air, and brushing. Quantification of the number, order, and duration of cleaning operations and description of equipment used is required. The default installation condition for verification of the hole cleaning procedure is dry concrete. Verification in water-saturated concrete is mandatory. Options include installation in water-filled holes and in submerged concrete (7.6 through 7.8 and 7.10 through 7.12). 2. Drilling method—The default drilling method uses a rotary hammer drill with carbide bit. Optional drilling methods for assessment includes core drilling and rock drilling (3.5). 3. Installation direction—Installation direction is the orientation of the axis of the anchor relative to gravity. Unless otherwise noted, the installation direction is vertically down. Optional installation directions for assessment extenuation are horizontal and vertical (7.18). 4. Installation temperature—The default concrete temperature range during anchor installation is 10 to 27°C. Options include installation at lower concrete temperatures (8.6).

12


5. Embedment depth and anchor diameter—The anchor diameters and associated embedment depth range are specified by the manufacturer within the ranges permitted by this standard (refer to Chapter 1). 6. Anchor element type—Anchor element types used in the anchorage system include different steel material types such as carbon and stainless steels, different tensile strengths of the steel, and different anchor elements such as threaded rods, reinforcing bars, and internally threaded inserts (3.4). 7. Environmental use conditions—Default conditions are dry and wet environments with service temperatures ranging from –40°C to the maximum long- and shortterm service temperatures corresponding to the temperature categories given in Table 8.1. 8. Chemical exposure—The default exposure condition is high alkalinity in a wet environment. The optional exposure condition is sulfur dioxide (8.8). 9. Concrete condition—Options include uncracked concrete or uncracked and cracked concrete. 10. Loading—Default loading conditions are static loading including sustained loads. Qualification for seismic loading is optional in conjunction with qualification for cracked concrete (8.12 and 8.13). 11. Member thickness—The default minimum member thickness is hef,min + Δh. Refer to 1.2.1 for hef,min and 10.7 for Δh. For smaller values of Δh, tests shall be conducted to verify that holes may be drilled and anchors installed without concrete spalling on the backside of the member for specific ratios of hef /h. 3.2.2 Limitations on conditions of use as a function of which optional tests are performed are described in 10.22.1. 3.3—Test requirements R3.3 This standard makes a fundamental distinction between anchors qualified for use exclusively in concrete that is expected to remain uncracked over the service life of the anchorage and anchors qualified for use in concrete that may be cracked or uncracked over the service life of the anchorage. Table 3.1 addresses qualification for use in uncracked concrete only, while Table 3.2 addresses cracked concrete qualification as well as qualification for seismic loading. Note that qualification for seismic loading can only be conducted in the context of qualification for cracked concrete. Table 3.3 provides an abbreviated test program for anchors to be qualified for use in cracked concrete, but without the option to achieve qualification for seismic loading. 3.3.1 Test requirements for adhesive anchors assessed to resist static loads in uncracked concrete conditions are defined in Table 3.1. 3.3.2 Test requirements for adhesive anchors assessed to resist static loads in both cracked and uncracked concrete conditions are defined in Tables 3.2 and 3.3. The reduced test program in Table 3.3 is associated with a predefined and conservative value for the ratio of characteristic limiting bond stresses in uncracked and cracked concrete. For optimization of the predicted strength of anchors in cracked

concrete conditions, the entire test program outlined in Table 3.2 must be conducted. 3.3.3 Test requirements for adhesive anchors to be assessed to resist seismic loads are defined in Table 3.2. Tables 3.1 and 3.3 may not be used to assess anchors to resist seismic loads. 3.4—Assessment for multiple anchor element types for adhesive anchors R3.4 When tests are performed on one type of anchor material such as carbon steel-threaded rod and the qualification is intended to include other types of threaded rod, such as stainless steel or hot-dip galvanized rod, then the testing and assessment of the adhesive anchor system is conducted for the primary rod type (usually carbon steel) and supplementary tests are conducted using the second rod type in accordance with Table 3.4. This abbreviated testing and assessment is primarily intended to address change in the torque-tension relationship associated with different rod materials, coatings, and thread types (ANSI/ASME B1.1 1989). If the additional testing performed using Table 3.4 indicates significant differences between the bond stresses of the two anchor elements, then repeat the entire test program for the anchor element. 3.4.1 When the assessment encompasses multiple anchor element material types such as carbon and stainless steel, the entire assessment shall be permitted to be performed with one anchor type; however, the other anchor element types shall be subjected to additional tests in accordance with Table 3.4. 3.5—Assessment for alternate drilling methods R3.5 Hammer drilling and rock drilling are assumed to produce similar hole wall characteristics from the standpoint of bond strength development. Drilling with diamond core bits, dry or wet, produces a smoother hole wall with a layer of drilling slurry or dust that can impair bond development. 3.5.1 Qualification of anchors using drilling methods other than carbide bit rotary-hammer must meet the requirements noted in 3.5.1.1 and 3.5.1.2. 3.5.1.1 Perform supplemental tests in accordance with Table 3.5 using the alternate drilling method. Install anchors in accordance with the MPII. 3.5.1.2 Results of supplemental testing required in Table 3.5 must be compared to corresponding tests conducted using a carbide rotary-hammer bit. If the comparison does not indicate statistical equivalence in test results between carbide rotary-hammer drilling and the alternative drilling method, then the alternative drilling method must be qualified using the test requirements of 3.3. There are, however, two exceptions: 1) testing for shear capacity of the anchor element need not be repeated. Additional testing for shear capacity of the anchor element is not required and may be omitted (Table 3.1, Test 12; Table 3.2, Test 16; or Table 3.3, Test 13); and 2) testing using a carbide rotary-hammer drill shall also be valid for percussive drilling, like pneumatic rock drilling, without supplementary tests. Testing using percussive drilling,


13

Table 3.1—Test program for evaluating adhesive anchor systems in uncracked concrete Testing Test no.

Test reference

1a

Chapter 6

1b

Chapter 6

2a

7.5

2b

7.6

2c

7.7

2d

7.8

2e

7.9

2f**

7.10

2g

7.11

2h

7.12

3

7.16

Sensitivity to freezing/thawing conditions

Sustained tension, residual capacity, confined test

0.90

4

7.17

Sensitivity to sustained load


0.90

5

7.18

Sensitivity to installation direction§

Tension, confined, single anchor away from edges

0.90

6

7.19

Torque test‡‡

Application of torque, confined, single anchor away from edges Service-condition tests

7a

8.4

Tension in low-strength concrete

Tension, unconfined, single anchor away from edges§§

—

7b

8.4

Tension in high-strength concrete||||

Tension, unconfined, single anchor away from edges§§

—

8a

8.5

Tension at elevated temperatures


—

8b

8.6

Tension at decreased installation temperature§

Tension, confined single anchor away from edges

—

8c

8.7

Curing time at standard installation temperature


—

9a

8.8

Resistance to alkalinity

Slice tests

—

10.4.2 10.4.4 10.4.5 10.4.2 10.4.4 10.4.5 10.4.2 10.4.4 10.13 10.4.2 10.4.4 10.14 10.4.2 10.4.4 10.15 10.16

9b

8.8

Resistance to sulfur§ Edge distance in corner condition to develop full capacity

—

10.16

10

8.9

11

8.10

12

8.11

13

9.1

14

9.2

Purpose

Test parameters Reference tests Reference tension in Tension, confined, single anchor away low-strength concrete from edges Reference tension in Tension, confined, single anchor away high-strength concrete from edges Reliability tests Sensitivity to hole cleaning, dry Tension, confined, single anchor away substrate from edges Sensitivity to hole cleaning, installation Tension, confined, single anchor away in water-saturated concrete from edges Sensitivity to hole cleaning, installation Tension, confined, single anchor away from edges in a water-filled hole§ Sensitivity to hole cleaning, Tension, confined, single anchor away from edges installation in submerged concrete§ Tension, confined, single anchor away Sensitivity to mixing effort from edges Sensitivity to installation Tension, confined, single anchor away in water-saturated concrete from edges Sensitivity to installation Tension, confined, single anchor away from edges in a water-filled hole§ Sensitivity to installation in submerged Tension, confined, single anchor away from edges concrete§

Assessment Load and αreq displacement

Slice tests Tension, unconfined single anchor in corner with proximate edges## High installation tension (torque or Minimum spacing and edge distance to unconfined tension), two anchors near preclude splitting an edge## Shear capacity of steel element having a Shear, single anchor away from edges non-uniform cross section*** Round-robin tests for regional concrete Tension, confined and unconfined variation single anchor away from edges Minimum member thickness§

Installation tests##

fc*

—

—

low

—

—

high

10.4.6 10.4.6 10.4.6 10.4.6 10.4.6 10.4.6 10.4.6 10.4.6

—

10.4.2 10.4.4 10.4.2 10.4.4 10.4.2 10.4.4 10.4.2 10.4.4 10.4.2 10.4.4 10.4.2 10.4.4 10.4.2 10.4.4 10.4.2 10.4.4 10.4.2 10.4.4 10.10 10.4.2 10.4.4 10.11 10.4.2 10.4.4 10.12 10.8

hef†

Minimum sample size nmin

min Five per max concrete batch Five per min concrete batch

low

max

Five‡

low

max

Five‡

low

max

Five‡

low

max

Five||

low

max

Five#

low

max

Five‡

low

max

Five‡

low

max

Five||

high

min††

Five#

low

min††

Five#

low

max

Five#

high

min

Five||

low

min max

Five||

high

min

Five||

low

min

Five#

low

min

Five#

low

min

Five#

low

—

Ten#

low

—

Ten# Four||

—

10.17

low

min max

—

10.18

low

min

Five||

—

10.6

low

min

Five||

—

10.4.1

low†††

7da

Five#

—

10.7

low

max

Ten||

*For definition of high- and low-strength concrete, refer to 4.3.4. †Where MPII specifies multiple embedment depths for single anchor diameter, test anchor at minimum or maximum embedment depth as noted, whereby h ef,max/hef,min ≤ 5.0 (4.7.2). ‡Test small, medium, and large diameters. §Optional test. ||Test all diameters. #Test the nominal M12 diameter or the smallest nominal diameter if it is larger than M12. For overhead and horizontal orientations, test the largest diameter for which recognition is sought.

For tests conducted in accordance with 9.1, tests shall be performed with a nominal M12 anchor only.

**Test 2f may be omitted if Test 2g is performed. ††Refer to 4.7.2.2. ‡‡Refer to 3.4 for multiple anchor element types. §§Alternatively, tests may be performed as confined tests. ||||Tests are optional if test results of Test 1b can be shown to be statistically equivalent to or greater than the results of Test 1a. If Test 7b is not performed, limit the calculated anchor

tension resistance to fc′ = 17 MPa regardless of the in-place concrete strength. ##Use minimum member thickness h min for these tests. ***Test is required only for anchors having a cross-sectional area, within five anchor diameters of the shear failure plane, that is less than that of a threaded bolt having the same nominal diameter as the anchor. †††Test in concrete having a measured compressive strength of 21 ± 3.5 MPa at the time of testing.

14


Table 3.2—Test program for evaluating adhesive anchor systems for cracked and uncracked concrete (cont.) Assessment

Testing Test no.

Test reference

Purpose

Test parameters

Crack width Δw, mm

αreq

Load and displacement

fc*

hef

†


Reference tests 1a

Chapter 6

Reference tension in low-strength concrete


—

—

—

low

min max

Five per concrete batch

1b

Chapter 6

Reference tension in low-strength, cracked concrete


0.3

—

—

low

min


1c

Chapter 6

Reference tension in high-strength concrete


—

—

—

high

min


1d

Chapter 6

Reference tension in high-strength, cracked concrete‡


0.3

—

—

high

min


—

10.4.6

10.4.2 10.4.4

low

max

Five§

Reliability tests 2a

7.5

Sensitivity to hole cleaning, dry substrate Tension, confined, single anchor away from edges

2b

7.6

Sensitivity to hole cleaning, installation Tension, confined, single anchor away in water-saturated concrete from edges

—

10.4.6

10.4.2 10.4.4

low

max

Five§

2c

7.7

Sensitivity to hole cleaning, installation Tension, confined, single anchor away from edges in a water-filled hole||

—

10.4.6

10.4.4 10.4.4

low

max

Five§

2d

7.8

Sensitivity to hole cleaning, installation Tension, confined, single anchor away from edges in submerged concrete||

—

10.4.6

10.4.4

low

max

Five#

2e

7.9

Sensitivity to mixing effort


—

10.4.6

10.4.2 10.4.4

low

max

Five**

2f ††

7.10

Sensitivity to installation in water-saturated concrete


—

10.4.6

10.4.2 10.4.4

low

max

Five§

2g

7.11

Sensitivity to installation in a water-filled hole||


—

10.4.6

10.4.2 10.4.4

low

max

Five§

2h

7.12

Sensitivity to installation in submerged Tension, confined, single anchor away from edges concrete||

—

10.4.6

10.4.2 10.4.4

low

max

Five#

3

7.13

Sensitivity to crack width in low-strength concrete


0.5

0.80

10.4.4 10.4.4

low

min

Five§

4

7.14

Sensitivity to crack width in high-strength concrete‡


0.5

0.80

10.4.2 10.4.4

high

min

Five§

5

7.15

Sensitivity to crack width cycling

0.90

10.4.2 10.4.4 10.9

low

min

Five #

6

7.16



—

0.90

10.4.2 10.4.4 10.10

high

min‡‡

Five**

7

7.17



—

0.90

10.4.2 10.4.4 10.11

low

min‡‡

Five**

8

7.18

Sensitivity to installation direction||


—

0.90

10.4.2 10.4.4 10.12

low

max

Five**

9

7.19

Torque test§§

Application of torque, confined, single anchor away from edges

—

—

10.8

high

min

Five#

Sustained tension, single anchor away from edges, residual capacity, 0.1 to 0.3 confined test

Service-condition tests 11a

8.4


Tension, unconfined, single anchor away from edges

—

—

10.4.2 10.4.4 10.4.5

low

min max

Five#

11b

8.4

Tension in high-strength concrete‡


—

—

10.4.2 10.4.4 10.4.5

high

min

Five#

11c

8.4

Tension in low-strength, cracked concrete


0.3

—

10.4.2 10.4.4 10.4.5

low

min

Five#

11d

8.4

Tension in high-strength, cracked concrete‡


0.3

—

10.4.2 10.4.4 10.4.5

high

min

Five#

12a

8.5

Tension at elevated temperatures


—

—

10.4.2 10.4.4 10.13

low

min

Five **

12b

8.6

Tension at decreased installation temperature||


—

—

10.4.2 10.4.4 10.14

low

min

Five**

12c

8.7



—

—

10.4.2 10.4.4 10.15

low

min

Five**


15

Table 3.2—Test program for evaluating adhesive anchor systems for cracked and uncracked concrete (cont.) Testing

Assessment

Test no.

Test reference

Purpose

Test parameters

Crack width Δw, mm

13a

8.8


Slice tests

13b

8.8

Resistance to sulfur||

Slice tests

14

8.9

Edge distance in corner condition to develop full capacity

Tension, unconfined single anchor in corner with proximate edges##

—

—

15

8.10

High installation tension (torque or Minimum spacing and edge distance to unconfined tension) two anchors near preclude splitting an edge##

—

16

8.11

Shear capacity of anchor element having a non-uniform cross section

Shear, single anchor away from edges***

17

8.12

Seismic tension||

18

8.13

19 20


αreq


fc*

hef

—

—

10.16

low

—

Ten**

—

—

10.16

low

—

Ten**

10.17

low

min max

Four#

—

10.18

low

min

Five#

—

—

10.6

low

min

Five#

Pulsating tension, single anchor away from edges

0.5

—

10.4.2 10.4.4 10.19

low

min max

Five#

Seismic shear||

Alternating shear, single anchor away from edges

0.5

—

10.20

low

min

Five§

9.1

Round-robin tests for regional concrete variation

Tension, confined and unconfined single anchor away from edges

—

—

10.4.1

low†††

7da

Five**

9.2

Minimum member thickness||


—

—

10.7

low

max

Ten#

†

* For definition of high- and low-strength concrete, refer to 4.3.4. † Where MPII specify multiple embedment depths for single anchor ‡

diameter, test anchor at minimum or maximum embedment depth as noted, whereby hef,max/hef,min ≤ 5.0 (4.7.2). Tests are optional if test results of Test 1c can be shown to be statistically equivalent to or greater than results of Test 1a. If any of Tests 1d, 4, 11b, and 11d are not performed, limit calculated anchor tension resistance to fc′ = 17 MPa. § Test small, medium, and large diameters. || Optional test. # Test all diameters. ** Test the nominal M12 diameter or the smallest nominal diameter if it is larger than M12. For overhead and horizontal orientations, test the largest diameter for which recognition is sought. For tests conducted in accordance with Section 9.1, tests shall be performed with a nominal M12 anchor only. †† Test 2f may be omitted if Test 2g is performed. ‡‡ Refer to Section 4.7.2.2. §§ Refer to Section 3.4 for multiple anchor element types. ## Use minimum member thickness hmin for these tests. *** Test is required only for anchors having a cross-sectional area, within five anchor diameters of the shear failure plane, that is less than that of a threaded bolt having the same nominal diameter as the anchor. ††† Test in concrete having a measured compressive strength of 21 MPa ± 3.5 MPa at the time of testing.

Table 3.3—Reduced test program for evaluating adhesive anchor systems in cracked and uncracked concrete (cont.) Testing Test no.

Test reference

Purpose

Test parameters

Crack width Δw, mm

Assessment αreq


fc

*

hef

†


Reference tests 1a

Chapter 6

Reference tension in low-strength concrete


—

—

—

low

min max


1b

Chapter 6

Reference tension in high-strength concrete


—

—

—

high

min


2a

7.5

Sensitivity to hole cleaning, dry substrate


—

10.4.6

10.4.2 10.4.4

low

max

Five‡

2b

7.6

Sensitivity to hole cleaning, installation in water-saturated concrete


—

10.4.6

10.4.2 10.4.4

low

max

Five‡

2c

7.7

Sensitivity to hole cleaning, Tension, confined, single anchor away from edges installation in a water-filled hole§

—

10.4.6

10.4.2 10.4.4

low

max

Five‡

2d

7.8

Sensitivity to hole cleaning, installation in submerged concrete§


—

10.4.6

10.4.2 10.4.4

low

max

Five||

2e

7.9

Sensitivity to mixing effort


—

10.4.6

10.4.2 10.4.4

low

max

Five#

2f**

7.10

Sensitivity to installation in water-saturated concrete


—

10.4.6

10.4.2 10.4.4

low

max

Five‡

2g

7.11

Sensitivity to installation in a water-filled hole§


—

10.4.6

10.4.2 10.4.4

low

max

Five‡

2h

7.12

Sensitivity to installation in submerged concrete§


—

10.4.6

10.4.2 10.4.4

low

max

Five||

Reliability tests

16


Table 3.3—Reduced test program for evaluating adhesive anchor systems in cracked and uncracked concrete (cont.) Testing Test no.

Test reference

Crack width Δw , mm

Assessment


αreq


fc

low

min

Five||

Purpose

Test parameters

0.1 to 0.3

0.90

10.4.2 10.4.4 10.9

*

hef

†

3

7.15


Sustained tension, single anchor away from edges, residual capacity, confined test

4

7.16



—

0.90

10.4.2 10.4.4 10.10

high

min††

Five#

5

7.17



—

0.90

10.4.2 10.4.4 10.11

low

min††

Five#

6

7.18

Sensitivity to installation direction§


-—

0.90

10.4.2 10.4.4 10.12

low

max

Five#

7

7.19

Torque test‡‡

Application of torque, confined, single anchor away from edges

—

—

10.8

high

min

Five||

Service-condition tests 8a

8.4



—

—

10.4.2 10.4.4 10.5

low

min max

Five||

8b

8.4

Tension in high-strength concrete§§


—

—

10.4.2 10.4.4 10.5

high

min

Five||

9a

8.5

Tension at elevated temperatures Tension, confined single anchor away from edges

—

—

10.4.2 10.4.4 10.13

low

min

Five#

9b

8.6

Tension at decreased installation Tension, confined single anchor away from edges temperature§

—

—

10.4.2 10.4.4 10.14

low

min

Five#

9c

8.7



—

—

10.4.2 10.4.4 10.15

low

min

Five#

10a

8.8


Slice tests

—

—

10.16

low

-

Ten#

Slice tests

—

—

10.16

low

-

Ten#

Tension, unconfined single Edge distance in corner condition anchor in corner with proximate to develop full capacity edges##

—

—

10.17

low

min max

Four||

High installation tension (torque or unconfined tension), two anchors near an edge##

—

—

10.18

low

min

Five||

Shear capacity of anchor element Shear, single anchor away from having a non-uniform cross edges*** section

—

—

10.6

low

min

Five||

§

10b

8.8

11

8.9

12

8.10

13

8.11

14

9.1

Round-robin tests for regional Tension, confined and unconfined concrete variation single anchor away from edges

—

—

10.4.1

low†††

7da

Five#

15

9.2

Minimum member thickness§

—

—

10.7

low

max

Ten||

Resistance to sulfur

Minimum spacing and edge distance to preclude splitting

* For definition of high- and low-strength concrete, refer to 4.3.4. † Where MPII specify multiple embedment depths for single anchor ‡ Test small, medium, and large diameters. § Optional test. || Test all diameters. #


diameter, test anchor at minimum or maximum embedment depth as noted, whereby hef,max/hef,min ≤ 5.0 (4.7.2).

Test nominal M12 diameter or smallest nominal diameter if it is larger than M12. For overhead and horizontal orientations, test largest diameter for which recognition is sought. For tests conducted in accordance with 9.1, tests shall be performed with nominal M12 anchor only.

** Test 2f may be omitted if Test 2g is performed. †† Refer to 4.7.2.2. ‡‡ Refer to 3.4 for multiple anchor element types. §§

Tests are optional if test results of Test 1b can be shown to be statistically equivalent to or greater than results of Test 1a. If Test 8b is not performed, limit calculated anchor tension resistance to fc′ = 17 MPa. minimum member thickness hmin for these tests. Test is required only for anchors having cross-sectional area within five anchor diameters of the shear failure plane that is less than that of threaded bolt having same nominal diameter as anchor. ††† Test in concrete having measured compressive strength of 21 ± 3.5 MPa at time of testing. ## Use ***


17

Table 3.4—Additional tests required for assessment of multiple anchor element types in accordance with 3.4 Nature of variation from tested anchor element* Material†

Geometry

Surface coating

Reference

Test no.

—

X

X

Table 3.1

6

—

X

X

Table 3.2

9

—

X

X

Table 3.3

7

—

X

X

Table 3.1

10

—

X

X

Table 3.2

14

—

X

X

Table 3.3

11

—

X

X

Table 3.1

11

—

X

X

Table 3.2

15

—

X

X

Table 3.3

12

X

X

—

Table 3.1

12

X

X

—

Table 3.2

16

X

X

—

Table 3.3

13

X

X

—

Table 3.2

18

Purpose

Requirement

Torque test‡

Refer to Section 10.8

Corner test§


Minimum spacing and edge distance§


Shear test to determine shear capacity as governed by steel failure

Required for anchor elements with reduced cross section; refer to Section 8.11

Seismic shear test

Optional test; refer to Section 10.20

*

In cases where anchor element varies in more than one characteristic (for example, material, geometry, or surface coating), test requirements indicated for each variation shall apply. †For stainless steels, conduct tests as required for change in geometry. ‡In cases where results of torque testing can show statistical equivalence to tested anchor element type, repetition of corner and minimum spacing and edge distance tests shall be permitted to be omitted. § Where reference test results indicate that anchor element has statistically meaningful influence on bond stress, repeat entire test program for anchor element.

Table 3.5—Required supplemental tests for each alternative drilling method Test numbers to be conducted for each alternative drilling method Table no.

Reliability/installation safety

3.1

1a

1b

—

—

2a

2b

2d

2f

2g*

—

—

3.2

1a

1b

1c

1d

2a

2b

2c*

2d*

2f

2g*

2h*

3

4

2b

*

2d*

2f

*

2h*

—

—

1a

1b

1c

1d

2a

2c

*

Reliability/crack width

2c*

3.3 *

Reference

2g

2h

*

Optional tests required only if conditions of use associated with these tests are to be included for recognition.

however, shall not be valid for rotary-hammer drilling without supplemental tests, as described in 3.5. CHAPTER 4—REQUIREMENTS FOR TEST SPECIMENS, ANCHOR INSTALLATION, AND TESTING 4.1—Testing by ITEA and manufacturer The minimum number of reference, reliability, and service-condition tests given in Tables 3.1 through 3.3 of this standard shall be performed by the ITEA (Chapter 12). Results of additional tests performed by the manufacturer can be considered in the evaluation, only if the results are statistically equivalent to those of the ITEA. R4.1 It is required that the testing program be performed under the guidance and direction of a single qualified ITEA with experience in anchor testing. The primary testing laboratory may have specific tests performed by other qualified laboratories, but retains the overall responsibility for testing and evaluating the anchor system. Tests performed in the manufacturer’s laboratory shall only be considered for improvement of the statistical accuracy of a test series and must be shown to belong to the same data population by establishing statistical equivalency with test data developed by the primary laboratory or other ITEAs. 4.2—Test samples 4.2.1 The ITEA (Chapter 12) shall randomly select anchors for testing from a manufacturing or distribution

facility and verify the samples are representative of production of the manufacturer as supplied to the marketplace. R4.2.1 Practical considerations may dictate that sampling be performed at a distribution center instead of the manufacturing facility. Due diligence should be exercised by the ITEA to ensure the samples are representative of production in all cases. Methods for ensuring the integrity of randomly sampled product throughout the custody chain include stamping or signing over the packaging, recording serial and batch numbers, and photographing the sampled product. 4.2.2 To test newly developed anchor adhesives not in production, use samples produced by the expected production methods. After production has begun, perform identification and reference tests to verify the constituent materials have not changed and performance of the production anchors is statistically equivalent to the anchors originally evaluated. R4.2.2 The use of preproduction prototypes for testing to develop qualification data is foreseen by ACI 355.4M. The prototypes, however, must be produced using the production methods foreseen for the full-scale production and must be accompanied by a complete MPII. Supplemental testing of the production product to confirm validity of the prototype tests is required. 4.2.3 When internally threaded anchors are supplied without fastening items such as bolts, threaded rods, or nuts, the manufacturer shall specify the fastening items to be used.

18


4.2.4 The sample sizes given in Tables 3.1 through 3.3 are the minimum required to satisfy ACI 355.4M. The sample size may be increased at the discretion of the ITEA or manufacturer. 4.2.5 Where tension tests on anchor elements are required to establish steel properties, a minimum of three replicates shall be performed. 4.3—Concrete for test members 4.3.1 Concrete used in testing shall meet the requirements of 4.3. To assess the performance of an anchor for use in concrete outside of the scope of ACI 355.4M, additional tests consistent with the requirements of Tables 3.1 through 3.3 shall be conducted with that concrete. R4.3.1 As a rule, testing is conducted in concrete using portland cement, normalweight aggregate, and natural sand without cement replacements, admixtures, or other enhancements. The results of these tests are assumed to be generally applicable to a wide range of concrete mixture designs with modification factors applied to the bond strength or concrete breakout strength where applicable. Where specific qualification is desired for anchors used in lightweight concrete or concrete containing cement replacements, admixtures, or other enhancements such as to support increased design values over those provided for in ACI 318M, the test program must be repeated using mixture designs that employ the lightweight aggregate, cement replacement, admixture, or enhancement in question. 4.3.2 Coarse and fine aggregates in concrete shall comply with ASTM C33/C33M. The aggregate description shall include rock and mineral components, shape, hardness, and maximum size and grading specification. Use a maximum coarse aggregate size of either 19.0 or 25.0 mm. R4.3.2 The influence of aggregate type on bond strength is not well understood. Round-robin tests are required to minimize the potential impact of locally favorable or unfavorable aggregate types on the results of qualification testing. 4.3.3 For general qualification for use of the anchor system in normalweight concrete, use portland cement conforming to ASTM C150/C150M. The concrete mixture shall not include cement replacements such as slag cement, fly ash, and silica fume or limestone powder. If a concrete mixture is used for test members that do not conform to the mixture requirements listed herein, a description of the concrete mixture components and proportions shall be included in the test report. In this case, qualification will be specific to the tested concrete mixture. R4.3.3 Use of blended cements constitutes a nonstandard concrete mixture design. Use of lightweight aggregates can result in a reduction of bond strength. Where bond values in excess of those specified in ACI 318M, Appendix D, for adhesive anchors in lightweight concrete are required, these must be based on testing in lightweight concrete. 4.3.3.1 For qualification of anchors in lightweight concrete, all tests shall be conducted in lightweight concrete unless the default values in ACI 318M, Appendix D, are used. 4.3.4 Test anchors in test members cast of concrete within two nominal compressive strength ranges:

• •

Low-strength concrete: 17 to 28 MPa High-strength concrete: 46 to 60 MPa R4.3.4 The influence of concrete compressive strength (as measured in a uniaxial compressive test) on anchor bond strength is dependent on specific bonding properties of the adhesive anchor system and must be established by test. Tests are conducted in low- and high-strength concrete to assess whether there is a direct or inverse correlation between concrete compressive strength and bond strength for the adhesive anchor system in question. 4.3.5 Test members shall be at least 21 days old at the time of anchor installation and testing. R4.3.5 Testing of anchors in concrete less than 21 days old constitutes testing in a nonstandard concrete. 4.3.6 Refer to 9.1 for additional requirements in conjunction with round-robin testing for adhesive anchors. 4.3.7 It shall be permitted to test anchors, when required, in test members cast of concrete with a nominal compressive strength of 14 MPa; however, the results may not be normalized for any other strength concrete. R4.3.7 ACI 318M currently specifies a minimum concrete strength of 17 MPa. In prior codes, the minimum concrete compressive strength was 14 MPa. Testing in concrete with a compressive strength of 14 MPa may be necessary to validate the use of anchors in existing structures. The results of tests obtained in 14 MPa concrete may not be increased for use of anchors in higher concrete strengths. 4.4—Requirements for test members 4.4.1 Test members shall conform to the requirements of ASTM E488. Where the requirements of ASTM E488 conflict with this standard, the provisions of this standard shall take precedence. R4.4.1 ASTM E488 establishes general procedures for the testing of anchors in tension and shear. 4.4.2 Reliability tests and reference tests to which they are compared shall be conducted in the same batch of concrete. R4.4.2 Batch control (refer to Fig. R.4.1) is required for reference tests to ensure that the resultant α values reflect actual variations in anchor behavior, not concrete composition. 4.4.3 Casting, curing, and strength determination of test members 4.4.3.1 Cast test member either horizontally or vertically. If the test member is cast vertically, limit the maximum height of a concrete lift to 1.5 m. R4.4.3.1 Casting of test members in the vertical position provides for formed surfaces on the top and bottom sides of the test member and minimizes the effect of irregularities in the surface concrete on anchor performance. Care should be exercised in vertical casting that the casting process does not result in concrete with significant strength variation due to segregation and bleeding effects, especially in the case of lower-strength concrete. 4.4.3.2 Sample, mold, and cure compressive strength cylinders in accordance with ASTM C31/C31M. Cure cylinders to the same environmental conditions as the test member. Remove molds from cylinders concurrent with removal of forms and curing covers from the test member.


19

Fig. R4.1—Concept of concrete batches. 4.4.3.3 Determine test member concrete compressive strength at the time of anchor testing from compression tests conducted on concrete cylinders in accordance with ASTM C39/C39M or cores extracted from the test member in accordance with ASTM C42/C42M. The results of tests on cylinders and cores shall not be combined for the establishment of the mean compressive strength at a given concrete age. Determine mean strength test values from: (a) linear interpolation of a test series using the beginning and ending tests as endpoints; or (b) strength-age relationships developed using compression tests of concrete test members at various test ages. R4.4.3.3 Cylinder compressive strengths are preferable to concrete cores for the determination of member compressive strength. The potential differences in measured compressive strength resulting from tests on cores or on cylinders should be accounted for. 4.4.4 Test members for tests in uncracked concrete—Test members for tests in uncracked concrete shall be unreinforced except as required to permit efficient handling of the test member or distribution of reaction loads from test equipment. Position such reinforcement so that the capacity of the tested anchor is not affected. For concrete breakout failure, this requirement is satisfied for anchors tested in tension if the reinforcement is located outside of a virtual cone projecting from the embedded end of the anchor to the concrete surface with an internal vertex angle of 120 degrees. Additionally, for splitting failure, reinforcement shall be omitted between the anchor location and the concrete edge. R4.4.4 Positioning of reinforcement as required for safe transportation of the test member should consider the potential formation of concrete breakout surfaces. Where anchors are to be tested in tension, reinforcement should be placed near the surface and toward the outer edges of the member. Where anchors are to be tested in shear, reinforcement should not be placed near the surface or corners of the test member. 4.4.5 Test members for tests in cracked concrete—Test members for tests in cracked concrete shall be designed to produce cracks of reasonably constant width throughout the thickness of the component. The cracks should be spaced sufficiently apart to facilitate testing of individual anchors placed in a crack without influence from adjacent cracks. For test members that use internal reinforcement to control the crack width or for specimen handling, place the reinforcement

Fig. 4.1—Example of test slab for testing in cracked concrete. so there is no influence on the anchor performance. Refer to Fig. 4.1 for an example test slab configuration. R4.4.5 For additional guidance on preparing and testing in cracked concrete, refer to Eligehausen et al. (2004). 4.4.5.1 Control the crack width using embedded reinforcing bars oriented perpendicular to the intended crack plane and distributed symmetrically over the test member cross section. The ratio of tension reinforcement for top and bottom layers to the area of the crack plane shall be approximately 1 percent. 4.4.5.2 The crack control reinforcement shall be permitted to cross the potential concrete cone breakout surface associated with the test anchor. The centerline-tocenterline distance between any crack control reinforcement and the anchor shall not be less than 0.4hef. Greater values for spacing of reinforcement are allowed as in the case of narrow concrete components, for example: width x depth = 500 mm x 250 mm where it is ensured that planar cracks of uniform width throughout the thickness of the component are produced and the crack width requirements of ACI 355.4M are satisfied. Furthermore, smaller values for center-to-center distance between reinforcement and anchor are allowed in the case of deep embedments where the anchorage mechanism is not influenced by the reinforcement. It shall be permitted to

20


Fig. 4.2—Example of test rig for testing in cracked concrete. debond reinforcement over a length of 75 mm on either side of the anticipated crack plane location using tape, plastic tubing, or other debonding agents. 4.4.5.3 An acceptable method for crack formation and crack opening is described in 4.4.5.4. Other methods shall be permitted subject to the requirements of ACI 355.4M. 4.4.5.4 Initiate and control the crack progression with planar sheet metal shapes, or crack initiators, placed in the formwork prior to casting of the test member. Position crack initiators so the capacity of the tested anchor is not affected by their presence. Extend tension reinforcing as required in 4.4.5 beyond the ends of the test member to facilitate application of external tension loads directly to the reinforcement. Apply external loading to both ends of the reinforcement to facilitate development of uniform strain over the length of the reinforcing. External loads for crack opening shall not be reacted against the test member. Support the test member to permit uniform tension strain distribution over the length of the test member. Refer to Fig. 4.2 for an example test setup. 4.4.5.5 The average crack width for each test series, measured by the two-crack measurement devices for each anchor before the load application, shall be equal to or greater than the specified crack width for that test series. Individual crack widths shall be within ±15 percent of the specified crack width for the test series. 4.5—Anchor installation 4.5.1 General requirements 4.5.1.1 Install anchors according to the MPII, except as otherwise required in ACI 355.4M. R4.5.1.1 The MPII should be the sole source of information for the specified anchor installation unless modified by this standard.

4.5.1.2 Install anchors in a formed face of the concrete or in concrete with a steel-troweled finish. R4.5.1.2 Testing of anchors in shear and in confined tension should be conducted on a flat, smooth concrete surface. Preferably, formed concrete surfaces should be used for shear testing. 4.5.1.3 Drilled holes for anchors shall be within six degrees of perpendicular to the surface of the concrete test member. R4.5.1.3 The allowance of six degrees in the drilling angle is intended to permit use of a hand-held hammer drill. It is not intended that anchors should be installed with a six-degree tilt as a means of enhancing resistance to tension loads. 4.5.1.4 Components of the anchor on which the reliability and capacity depend shall not be exchanged. Bolts, nuts, and washers not supplied with the anchors shall conform to the specifications given by the manufacturer, which shall be included in the test report. R4.5.1.4 Substitution of bolts, nuts, and washers to achieve bond failure is permitted. 4.5.2 For installation of anchors in cracks, follow procedures in R4.5.2. R4.5.2 The creation of planar cracks in the test member is a matter of experience and may be influenced by the position and type of crack inducers, the type and position of reinforcement, and the method used to generate the necessary tensile stresses in the concrete. Positioning of the anchor in the crack is likewise a matter of judgment. Ideally, the crack runs vertically down the centerline axis of the anchor over its entire length. For anchors to be tested in tension, deviation of the crack position from the anchor centerline should be limited to the surface of the member. For anchors to be tested in shear, it is more important that the crack transect the anchor position at the concrete surface. These conditions are best confirmed using a boroscope. 4.5.2.1 With the test member unloaded, drill the hole for the anchor in a hairline crack that is sufficiently planar to ensure the crack will approximately bisect the anchor location over the embedment depth of the anchor. 4.5.2.2 Visually verify positioning of the anchor in the crack before installation by using a boroscope or similar device. 4.5.3 Unless otherwise specified in ACI 355.4M, adhesive anchors shall not be torqued prior to testing. R4.5.3 Unlike torque-controlled expansion anchors, adhesive anchors do not require the application of torque for proper set. 4.6—Drill bit requirements R4.6 Unlike some types of expansion anchors, adhesive anchors are generally insensitive to minor variations in drilled hole diameter. Bit wear should, nevertheless, be monitored during the test program. 4.6.1 Drill holes with a rotary-percussive hammer drill using carbide-tipped, hammer-drill bits meeting the requirements of ANSI B212.15. R4.6.1 For drill bits not covered by ANSI B212.15, for example, core bits, the ITEA shall measure and report the cutting diameter of the bits.


4.7—Test methods 4.7.1 Test anchors in conformance with ASTM E488 and this standard. Where differences occur, ACI 355.4M shall take precedence over ASTM E488. The recorded displacements should be corrected so that they represent the displacement at the concrete surface. R4.7.1 ASTM E488 provides general guidelines for testing anchors in tension and shear. It does not contain specific instructions for many of the tests described in this standard. 4.7.2 Configure tension tests used to establish the characteristic limiting bond stress so that bond failure is the controlling mode of failure. R4.7.2 In general, the objective of tension tests in ACI 355.4M is to measure the tension resistance of the adhesive anchor as governed by bond strength. Where either steel or concrete breakout failures occur, it may be assumed that the maximum potential bond strength associated with the adhesive anchor system is not reflected in the measured peak load. 4.7.2.1 To avoid steel failure, unconfined and confined tension tests may be performed with an anchor element having a documented strength exceeding the product specification, subject to: 1) the geometry and coatings of the substitute anchor element shall be identical to the product specification; or 2) it shall be demonstrated that the substitute anchor element does not affect the function or performance of the anchor. R4.7.2.1 For deeper embedments, it may be necessary to use a high-strength threaded rod to avoid steel failure. ASTM A193 B7 is a readily available high-strength threaded rod material. Heat-treatment may also be used to increase the rod strength. In all cases, the thread configuration should be representative of the threaded rod types included in the qualification of the adhesive anchor system. 4.7.2.1.1 An exception to this is in cases where use of a high-strength steel anchor element is insufficient to prevent steel failure (minimum strength equivalent to ASTM A193); the anchor embedment may be reduced accordingly. In cases where the embedment depth must be reduced to avoid failure modes other than bond failure, check the effectiveness of the MPII by other means; with respect to hole cleaning and injection at the unreduced maximum hole depth, also check by other means. The method described in 4.7.2.1.2 shall be permitted. R4.7.2.1.1 Where it is not possible to preclude steel failure for a specific embedment, it is permissible to reduce the bonded length to force a bond failure. When this step is taken, it is necessary to simulate the hole cleaning and adhesive injection processes for the full-depth hole condition by some other means. The use of stacked blocks is one such method. 4.7.2.1.2 For cases where the embedment depth must be reduced to avoid failure modes other than bond failure, the following test method shall be permitted for use to verify the installation method. Stack concrete blocks A and B, as shown in Fig. 4.3(a), as required to achieve the desired embedment and perform the drilling operation. Although the core drill is shown, other

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drilling methods may be used as appropriate. Seal the interface between the blocks. 1. Clean the hole in accordance with the procedures described in the MPII (Fig. 4.3(b)); 2. Perform adhesive injection in accordance with the procedures described in the MPII. Limit injection depth to the bottom block B (Fig. 4.3(c)); 3. Remove the upper block A and install the anchor element in accordance with the procedures described in the manufacturer’s published installation instructions (Fig. 4.3(d)); and 4. Perform a confined tension test to failure (Fig. 4.3(e)). R4.7.2.1.2 The use of stacked concrete blocks enables duplication of installation conditions, with respect to hole depth, while still enabling tension testing that results in bond failure as opposed to failure of the anchor element. Other methods may be used subject to assessment by the primary testing laboratory. 4.7.2.2 Proof of maximum bond stress for freezing-andthawing and sustained load tests—For establishing the sustained load applied in freezing-and-thawing and sustained load, tests and all other test series where hef,min is specified in Table 3.1, 3.2, or 3.3, it shall be demonstrated that Eq. (4-1) is fulfilled for the hef,min value used. If Eq. (4-1) is not satisfied with the results of unconfined tests, increase the embedment depth until Eq. (4-1) is satisfied; however, steel failure should be avoided in all tests. Alternatively, conduct confined tests with an embedment of approximately 7da in accordance with 4.7.3.2 and with the value No,i in accordance with Eq. (4-2). 1.5

No,i ≤ km f c, test, i h ef

N

(4-1)

where km equals 10 for tests conducted in uncracked concrete, and 7 for tests conducted in cracked concrete; No,i is the mean ultimate tension load as determined from unconfined tests, N; and fc,test,i is the concrete compressive strength in test series i, MPa. No,i = αsetup No,i,confined

N

(4-2)

where No,i,confined is the mean ultimate tension load measured in confined reference tests at hef ≈ 7da, N, and αsetup is the reduction factor for service-condition tests performed as confined tests in accordance with 10.4.5.1. R4.7.2.2 For sustained load tests, it is important that the sustained load is based on the maximum potential bond strength on which the anchor design will be based. Many adhesive anchor systems exhibit concrete breakout failure when tested in tension at minimum embedment. In these cases, it is necessary to increase the embedment to a point where bond failure occurs. The establishment of bond failure solely on the basis of physical observation of the failed specimen, however, is problematic. Development of fracture surfaces that do not project to the concrete surface may preclude the attainment of maximum potential bond strength. Comparison of the mean strength obtained in the tension tests with a predicted value for the concrete breakout

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Fig. 4.3—Establishing bond strength at deeper embedments: optional method to verify installation. strength serves to determine whether that value is representative of the maximum potential bond strength or reflects a premature concrete breakout failure. For cases where the resistance at the embedment required to promote bond failure exceeds the strength of the high-strength rods used for testing, confined tests may be performed and converted to unconfined values via the term α setup. 4.7.3 Unconfined and confined tension tests R4.7.3 This standard permits the use of confined testing for service-condition tests in cases where unconfined testing is either impractical or does not facilitate the assessment of the characteristic bond stress for the product. Table R4.1 provides guidance for the conduct of specific tests in accordance with ACI 355.4M. 4.7.3.1 Conduct unconfined tension tests where specified. Figure 4.4 shows a typical unconfined tension test setup whereby the supports are spaced a suitable distance from the anchor to permit unrestricted development of a conical concrete fracture surface. 4.7.3.2 Confined instead of unconfined tension tests may be conducted where permitted (Table 3.1, 3.2, or 3.3). Figure 4.5 shows a typical confined tension test setup for

adhesive anchors, whereby the reaction force is transferred into the concrete in close proximity to the anchor element. The hole in the confining plate shall be 1.5do to 2.0do and the thickness shall be greater than or equal to da. Place a sheet of tetrafluoroethylene (TFE), polytetrafluoroethylene (PTFE), fluorinated ethylene (FEP), or perfluoroalkoxy (PFA) of 0.5 ± 0.1 mm corresponding to the area of the confining plate between the confining plate and concrete surface to reduce friction. 4.7.3.3 Confined tests are specified primarily to reduce the size and quantity of concrete test members required. In no case shall the results of confined tests be compared with the results of unconfined tests, for example, for the determination of α (10.4.3). 4.8—Tests in cracked concrete 4.8.1 Perform tests in concrete test members meeting the requirements of 4.3. Initiate cracking in the test member. Install the anchor according to 4.5 so that the axis of the anchor is coincident with the crack plane. Install instrumentation for monitoring crack-opening width. Monitor crack-opening width using dial gauges or electronic transducers located roughly symmetrically on either side of the anchor on an axis


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Table R4.1—Confined and unconfined testing* Suitability test

Test configuration


Unconfined during crack cycling and confined for residual capacity

Reference test for establishing applied load†

Reference test for residual capacity

Unconfined

Confined


Confined

unconfined

Confined


Confined

Unconfined

Confined

Seismic tension load cycling

Unconfined or confined

Unconfined or confined depending on configuration of test during load cycling

NA

Seismic tension residual capacity

Unconfined or confined

NA

Unconfined or confined depending on configuration of residual capacity test

*

In no case are the results of confined tests compared with the results of unconfined tests.

†All reference tests should be configured to result in bond failure.

Fig. 4.4—Example of unconfined tension test setup for adhesive anchors. oriented perpendicular to the crack plane to permit interpolation for the crack width at the anchor location. Keep the distance from the crack width measurement point to the anchor centerline as small as possible; not to exceed the greater of 1.0hef or 125 mm. Increase the crack width by the specified crack value prior to applying external loads to the anchor. Verify by suitable means that the system used for crack formation and the associated test procedures produce cracks that remain parallel during the performance of tests. The crack width, as measured at the opposite face of the test member in line with the anchor location, or as estimated based on the crack width measurement on each side of the test member as close to the opposite face as possible, should be approximately equal to the crack width measured on the anchor side. Verification that the test procedure used for a specific test will produce the appropriate crack geometry shall be performed at the beginning of the test series. R4.8.1 The test specimen geometry and loading method are determinants in whether the cracks remain parallel over the depth of the member. It is important that the crack width measurement devices reflect the crack width at the anchor location. It is generally acceptable to check the performance of the specimen at the beginning of the test series.

Fig. 4.5—Example of confined tension test setup for adhesive anchors. 4.8.2 Subject the anchor to the specified loading sequence while monitoring the crack opening width at the surface as required in the specific test 4.8.3 Record the applied load, corresponding anchor displacement, and crack width during the test as required in the specific test. Use a sampling frequency appropriate for the load or strain rate employed for the test. 4.9—Changes to products 4.9.1 Prior to modifying an anchor adhesive system previously assessed in accordance with ACI 355.4M, the manufacturer shall report the nature and significance of the change in the system to the ITEA serving as the primary laboratory for the original assessment. The ITEA shall determine which tests, if any, shall be performed to determine whether the change in the adhesive anchor system is equivalent to the previously assessed adhesive anchor system.

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For all changes that might affect the anchor performance, the ITEA shall perform sufficient reference and reliability tests to assess the impact of the change. Test results shall be shown statistically equivalent to those of the originally tested product. If the results of the reference and reliability tests cannot be shown to be statistically equivalent to the results of the original testing, retest and evaluate the modified adhesive anchor system in accordance with ACI 355.4M. R4.9.1 Modifications to the adhesive anchor system that should trigger this provision include significant changes to the MPII including, but not limited to, changes to scope of use, hole cleaning methodology, injection technique, and listed cure times. Other changes include the adhesive formulation, adhesive confectioning, adhesive mixing and delivery system, and the supplementary tools and devices used to clean the drilled hole. CHAPTER 5—REQUIREMENTS FOR ANCHOR IDENTIFICATION 5.1—Basic requirements R5.1 The description of the adhesive anchor system should be developed by the ITEA based on information provided by the manufacturer. 5.1.1 Provide the following information in the evaluation report. 5.1.1.1 Product description, including: • Generic or trade name. • Anchor element dimensions; constituent materials; and appropriate physical properties including tensile strength, hardness, and coatings. • A description of the adhesive components including the adhesive name, packaging system, mixing ratios, gel time, cure time, storage information, and shelf life. 5.2—Verification R5.2 Additional testing as required to verify the components of the adhesive anchor system is at the discretion of the ITEA. 5.2.1 The testing and evaluation agency shall verify the characteristics reported in accordance with 5.1.1.1 against the manufacturer’s product specifications. 5.3—Fingerprinting adhesive materials R5.3 Fingerprinting the adhesive anchoring materials involves the performance of specific tests to establish a baseline of the adhesive material for comparing future batches of product. If the adhesive material is changed by the manufacturer, that change may or may not significantly affect the published performance of the anchor system. Selection of appropriate tests for comparison with future batches is a critical function. The use of alternate tests to address other materials is at the discretion of the ITEA. The fingerprinting tests may or may not be part of the manufacturer’s quality control system. 5.3.1 Test the adhesive material components used for the qualification testing to establish a standard fingerprint for comparison with future production of adhesive material in accordance with the required quality audits. It shall be permitted to test the components separately or their mixture,

as appropriate. The manufacturer shall select from the following list a minimum of three fingerprint tests for this purpose: • Infrared absorption spectroscopy—ASTM E1252 • Bond strength—ASTM C882/C882M or equivalent method • Specific gravity—ASTM D1875 • Gel time—ASTM C881/C881M • Viscosity—ASTM D2556, ASTM F1080, or equivalent method • Other tests that may be appropriate for the specific product that can be shown to provide positive identification 5.3.2 Test methods not described herein shall be proposed to and accepted by the ITEA prior to commencing tests. Other test methods shall be permitted if approved by the ITEA. 5.4—Packaging R5.4 The packaging of adhesive components in the adhesive anchor system should contain the information required in 5.4 in a legible and readily-understandable format. 5.4.1 Packaging of the adhesive materials shall include: • Manufacturer’s name and address • Lot number • Packing date and shelf life or product expiration date • MPII and application information CHAPTER 6—REFERENCE TESTS 6.1—Purpose R6.1 Reference tests form the basis for the adhesive anchor system when subjected to suboptimal conditions. As such, it is important that the concrete used for these tests is as closely related as possible to the concrete used for the suitability tests. Depending on the manner in which the reference tests are conducted, they may also serve as service-condition tests for the system (Chapter 8). 6.1.1 Reference tests are performed in each batch of concrete to obtain baseline values for reliability and service-condition tests where reference values are required to assess the effects of suboptimal hole cleaning, temperature variation, mixing effort, cracking, sustained load, installation direction, spacing, edge distance, type of loading (shear or tension), environmental exposure, and member thickness on anchor performance. 6.1.2 Unless otherwise noted, perform reference tests as confined tension tests (4.7.3). R6.1.2 The use of confined tests is based on two considerations: 1. Confined tests measure the bond strength of the anchorage as opposed to the concrete capacity associated with concrete failure modes such as concrete cone breakout. As such, they are suitable to assess the effects of temperature variation, suboptimal hole cleaning, mixing effort, sustained load, installation direction, temperature variations, and environmental exposure on anchor performance. 2. Confined tests do not generate large spall cones, and as such serve to reduce the volume of concrete required for the test program. 6.1.3 Reference tests shall be permitted to be performed as unconfined tension tests only if the service-condition tests


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Fig. 6.1—Example test layout. are also performed as unconfined tests. Where unconfined tension tests are used as reference tests, they shall be compared to unconfined reliability or service-condition tests. In all cases, bond failure is required (refer to 4.7.3). 6.2—Required tests R6.2 The use of confined tests serves to reduce the volume of concrete required for the tests, and may also be necessary to force bond failures for shallower embedments. Note the use of unconfined tests for reference tests can lead to an unconservative assessment if the unconfined reference tests result in concrete cone failures. One example is underrepresenting the maximum bond strength of the adhesive anchor system. 6.2.1 Required reference tests are given in Table 3.1 for anchors to be qualified for use in uncracked concrete only and in Table 3.2 or 3.3 for anchors to be qualified for use in both uncracked and cracked concrete. 6.2.2 Conduct reference tests in the same concrete batch used for the reliability or service-conditions tests to which they are compared. Reference tests may be used for comparison with more than one series of reliability or service-condition tests. Refer to Fig. 6.1 for an example test layout. 6.2.3 The anchor diameters for which reference tests are required shall correspond to requirements for the reliability or service-condition tests for which the reference tests are performed. 6.2.4 Reference tests for the assessment of tests conducted in uncracked concrete shall be performed in uncracked concrete. Reference tests for the assessment of tests conducted in cracked concrete shall be performed in cracked concrete. 6.2.5 It shall be permitted to perform additional reference tests (4.2.4). 6.3—Conduct of tests R6.3 Reference tests should be conducted under ideal laboratory conditions to avoid under-representing the bond strength of the adhesive anchor system. 6.3.1 Prepare test members, install anchors, and test in accordance with Chapter 4. 6.3.2 Perform tests listed in Chapter 3 under Reference Tests in dry concrete. 6.3.3 Perform tests listed in Chapter 3 under Reference Tests with air, concrete, and anchor at standard temperature.

CHAPTER 7—RELIABILITY TESTS 7.1—Purpose R7.1 Reliability tests are intended to check the sensitivity of the adhesive anchor system to foreseeable variations from optimal installation conditions. They are not pass-fail tests, but rather provide the necessary input for determining the characteristic maximum bond stress for the adhesive anchor system. 7.1.1. Reliability tests are performed to establish that the anchor is capable of safe, effective behavior under normal and adverse installation conditions. 7.2—Required tests R7.2 Required reliability tests are a function of the options selected for the assessment, including uncracked or cracked concrete assessment, admissible exposure conditions, and required job-site quality control measures. 7.2.1 Required reliability tests are given in Table 3.1 for adhesive anchors to be qualified for use in uncracked concrete only and in Table 3.2 or 3.3 for adhesive anchors to be qualified for use in both uncracked and cracked concrete. 7.2.2 Tests for the influence of drill tolerance on anchor behavior are not required. 7.3—Conduct of tests R7.3 Reliability tests should be conducted under ideal laboratory conditions to avoid under-representing the bond strength characteristics of the adhesive anchor system. 7.3.1 Prepare test members, install anchors, and test in accordance with Chapter 4 unless otherwise noted. 7.3.2 Perform tests in dry concrete except as required by specific tests. 7.3.3 Perform tests with air, concrete, and anchor at standard temperature unless otherwise noted. 7.4—Reliability tests R7.4 Reliability tests are not intended to sanction or otherwise imply acceptance of job-site variations from the MPII, nor do they ensure proper functioning under all possible and foreseeable job-site errors. While it is assumed that the on-site installation personnel will generally conform to the MPII, the potential for inadvertent deviations from the MPII, particularly with respect to hole cleaning procedures, forms the basis for many of the reliability tests.

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Gross installation errors as denoted in this section are not addressed by this standard and are assumed to be precluded by attention to worker training and job-site inspection and quality control practices. 7.4.1 Reliability tests are intended to assess the sensitivity of the tested system to variations in installation and servicecondition parameters that are likely experienced in practice. They are not intended to address gross installation errors. Gross installation errors are characterized by significant deviations from the MPII or design specifications and include, but are not limited to: • Deviations from the specified embedment depth • Use of a nominal diameter drill bit other than that specified • Incorrect assembly or operation of the adhesive mixing and dispensing equipment • Use of the product in base materials other than structural concrete • Use of the product in concrete exhibiting compressive strength outside of the specified range • Use of the product in base materials having a temperature outside of the specified range for the product • Violation of specified gel and cure times • Violation of storage and shelf life restrictions for the adhesive 7.5—Sensitivity to hole cleaning—dry concrete Refer to Table 3.1, Test 2a; Table 3.2, Test 2a; and Table 3.3, Test 2a. R7.5 Hole cleaning procedures can have a significant influence on bond strength. This reliability test checks for the sensitivity of anchor bond strength to suboptimal hole cleaning effort (50 percent) in dry concrete conditions. The MPII should provide necessary instructions for hole cleaning with the required degree of specificity to permit evaluation of the 50 percent hole cleaning effort. For example, if the MPII calls for blowing out the hole twice with compressed air followed by four insertions of a brush and two additional applications of compressed air, 50 percent effort would be assessed as one application of compressed air followed by two insertions of the brush and one application of compressed air. Where three repeats of a specific operation are specified, one should be performed; where one is specified, the cleaning step should be omitted. The type of brush, such as steel and nylon, and its diameter should be specified in the MPII together with any other details, such as air pressure, that might affect the effectiveness of the holecleaning process. If the MPII does not contain sufficient information to permit the establishment of a cleaning effort that represents 50 percent of the specified effort, hole cleaning should be omitted. An effective upper limit on repetitions of any single holecleaning operation of four is intended to prevent the specification of excessive hole cleaning effort in the MPII as a means of satisfying reliability test criteria. 7.5.1 Purpose—These reliability tests are used to assess the sensitivity of the anchor tension capacity to the degree of hole cleaning employed prior to anchor installation.

7.5.2 General test conditions—Perform confined tension tests in uncracked concrete. 7.5.3 The test description provided herein presumes a method of hole cleaning that includes cleaning the hole wall with a brush and blowing out the hole with air. Other cleaning methods are permitted; however, the MPII for the product shall contain sufficient specificity to permit the determination of a numeric (50 percent) reduction of hole cleaning effort. For hole cleaning methods involving brushing and blowing operations, such specificity shall include as a minimum: 1. Requirements for all equipment to be used in the hole cleaning process, including air/vacuum pressure, nozzle construction, and brush dimension and materials as applicable 2. Acceptable methods and minimum number and duration of operations required for removal of drilling debris from hole 3. Acceptable methods and minimum number and duration of operations required for removal of dust or drilling flour from the hole wall 4. The required sequence of operations An exception to determine the reduced hole cleaning effort, regardless of the number of hole cleaning operations specified in the MPII, the number of times the operation step is repeated in tests for reduced cleaning effort shall not exceed two. For the purposes of this section, an operation shall be considered to be an action that is repeated not more than three times in succession. 7.5.4 Drill the hole downward to the depth defined by the manufacturer. Clean the hole with 50 percent of the specified minimum number of operations in the specified sequence, rounding down to the next whole number of operations. So if a total of four brushing and four blowing operations are specified, install the anchor with only two brushing and two blowing operations. 7.5.4.1 If the MPII does not contain sufficient specificity with respect to hole cleaning as defined in 7.5.3, to permit the determination of a numeric reduction of hole cleaning effort per this section, or if the required equipment is not specified as defined in 7.5.3, conduct the tests without hole cleaning. Load the anchor to failure with continuous measurement of load and displacement. 7.6—Sensitivity to hole cleaning—saturated concrete Refer to Table 3.1, Test 2b; Table 3.2, Test 2b; and Table 3.3, Test 2b. R7.6 Hole cleaning procedures appropriate for dry concrete may be inappropriate for a hole drilled into saturated concrete due to the presence of wet drilling mud. It is anticipated that the MPII will contain specific procedures, such as flushing the hole with water, for cleaning holes drilled into saturated concrete or where the drilled hole has been subjected to water prior to the anchor installation (for example, from rain). Due to the likelihood that products will be installed in concrete exposed to water (such as concrete exposed to weather), these tests are mandatory.


7.6.1 Purpose—These reliability tests are used to assess the sensitivity of the adhesive material to hole cleaning for applications in water-saturated concrete. 7.6.2 General test conditions—Perform confined tension tests in uncracked concrete. 7.6.3 Qualification for use with carbide drill bits—Drill a pilot hole downward to the specified hole depth with a bit approximately half the diameter of the specified hole diameter. Fill the pilot hole with potable water and ensure that the hole remains flooded for a minimum of 8 days or 192 hours. Immediately prior to installing the anchor, remove all freestanding water with a vacuum and redrill the existing hole with the specified drill bit diameter. Clean the hole in accordance with the reduced cleaning effort specified in 7.5.3 and 7.5.4. Install the anchor in accordance with the MPII. Load the anchor to failure with continuous measurement of load and displacement. Other methods of achieving saturation of the concrete, such as immersing the test member, shall be permitted. If methods other than those described previously are used, it shall be shown by appropriate methods that the concrete in the area of the anchorage is water saturated. 7.6.4 Qualification for water-flushed holes—Redrill the pilot hole with the specified drill bit. If the MPII specifies flushing of the hole with water prior to anchor installation, it shall be permitted to flush the hole with potable water prior to installing the anchors. Prepare the hole with reduced cleaning effort in accordance with 7.6.3. Immediately prior to installing the anchors, remove freestanding water from the hole with a vacuum. Install the anchor in accordance with the MPII. Load the anchor to failure with continuous measurement of load and displacement. 7.7—Sensitivity to hole cleaning—water-filled hole Refer to Table 3.1, Test 2c; Table 3.2, Test 2c; and Table 3.3, Test 2c. R7.7 For installation of adhesive anchors in water-filled holes, specific instructions should be provided in the MPII. These tests are optional; however, failure to assess this condition will result in restrictions on the use of the adhesive anchor system. 7.7.1 Purpose—These optional reliability tests are used to assess the sensitivity of the adhesive material to hole cleaning for applications in water-saturated concrete where the drilled holes contain standing water at the time of anchor installation. 7.7.2 General test conditions—Perform confined tension tests in uncracked concrete. 7.7.3 Qualification for use with carbide drill bits— Prepare and clean the hole in accordance with 7.6.3; however, refill the hole with potable water immediately prior to installing the anchor and install the anchor in the waterfilled hole. Load the anchor to failure with continuous measurement of load and displacement. 7.7.4 Qualification for water-flushed holes—Prepare and clean the hole in accordance with 7.6.4; however, refill the hole with potable water immediately prior to installing the anchor. Install the anchor in accordance with the MPII. Load the anchor to failure with continuous measurement of load and displacement.

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7.8—Sensitivity to hole cleaning—submerged concrete Refer to Table 3.1, Test 2d; Table 3.2, Test 2d; and Table 3.3, Test 2d. R7.8 For installation of adhesive anchors in submerged concrete, specific instructions should be provided in the MPII. These tests are optional; however, failure to assess this condition will result in restrictions on the use of the adhesive anchor system. 7.8.1 Purpose—These optional reliability tests are used to assess the sensitivity of the adhesive material to hole cleaning for applications in submerged concrete. 7.8.2 General test conditions—Perform confined tension tests in uncracked concrete. 7.8.3 Cover the surface of the water-saturated concrete test member with potable water to a minimum depth of 13 mm for the duration of the test, including anchor installation and tension testing. Drill the hole downward in the submerged concrete, clean the hole in accordance with the reduced cleaning effort specified in 7.5.3 at 50 percent of the cleaning efforts given in the MPII for this application, and install the anchor in accordance with the MPII. Load the anchor to failure with continuous measurement of load and displacement. 7.9—Sensitivity to mixing effort Refer to Table 3.1, Test 2e; Table 3.2, Test 2e; and Table 3.3, Test 2e. R7.9 For adhesive anchor systems that do not use automatic metering and mixing systems, it is necessary to check the sensitivity of the system to suboptimal mixing of the adhesive components. 7.9.1 Purpose—These reliability tests are used to assess the sensitivity of the adhesive material to mixing effort. These tests are required only for those anchor systems where the mixing of the adhesive material is substantially controlled by the installer. Such cases include systems that require components to be mixed until a color change is effected throughout the adhesive material, the adhesive materials to be mixed with recommended equipment for a specific duration, and the adhesive materials be mixed with a repetitive mixing operation a specific number of times. 7.9.1.1 These tests are not required for capsule anchor systems or cartridge or bulk systems that employ automatic metering and mixing through a manifold and disposable mixing nozzle. 7.9.2 General test conditions—Perform confined tension tests in uncracked concrete. 7.9.3 Conduct tests as required to establish the required time for full mixing using standard mixing equipment. Reduced mixing effort shall be achieved by decreasing the mixing time required for full mixing by 25 percent. Load the anchor to failure with continuous measurement of load and displacement. 7.10—Sensitivity to installation in water-saturated concrete Refer to Table 3.1, Test 2f; Table 3.2, Test 2f; and Table 3.3, Test 2f.

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R7.10 For systems used only in conjunction with increased levels of job-site quality control (for example, continuous inspection and proof loading), lower thresholds are established for the reliability tests. It is therefore necessary to perform supplemental checks for the sensitivity of the adhesive anchor system to installation in water-saturated concrete where the full cleaning effort in accordance with the MPII is used. 7.10.1 Purpose—These reliability tests are used to independently assess the sensitivity of the adhesive material to applications in water-saturated concrete where the anchor category shall be determined in accordance with Table 10.6. 7.10.2 General test conditions—Perform tests in accordance with 7.6; however, hole cleaning shall be conducted in accordance with the MPII. 7.11—Sensitivity to installation in water-filled hole—saturated concrete Refer to Table 3.1, Test 2g; Table 3.2, Test 2g; and Table 3.3, Test 2g. R7.11 For systems used only in conjunction with increased levels of job-site quality control (for example, continuous inspection and proof loading), lower thresholds are established for the reliability tests. It is therefore necessary to perform supplemental checks for the sensitivity of the adhesive anchor system to installation in water-filled holes where the full cleaning effort in accordance with the MPII is used. 7.11.1 Purpose—These optional reliability tests are used to independently assess the sensitivity of the adhesive material to applications in water-filled hole in saturated concrete for cases where the anchor category shall be determined in accordance with Table 10.6. 7.11.2 General test conditions—Perform tests in accordance with 7.7; however, hole cleaning shall be conducted in accordance with the MPII. 7.12—Sensitivity to installation in submerged concrete Refer to Table 3.1, Test 2h; Table 3.2, Test 2h; and Table 3.3, Test 2h. R7.12 For systems used only in conjunction with increased levels of job-site quality control (for example, continuous inspection and proof loading), lower thresholds are established for the reliability tests. It is therefore necessary to perform supplemental checks for the sensitivity of the adhesive anchor system to installation in submerged concrete where the full cleaning effort in accordance with the MPII is used. 7.12.1 Purpose—These optional reliability tests are used to assess the sensitivity of the adhesive material to applications in submerged concrete where the anchor category shall be determined in accordance with Table 10.6. 7.12.2 General test conditions—Perform tests in accordance with 7.8; however, hole cleaning shall be conducted in accordance with the MPII. 7.13—Sensitivity to crack width—low-strength concrete Refer to Table 3.2, Test 3.

R7.13 The effect of upper-bound service-condition cracking on the tension resistance of adhesive anchors in low-strength concrete is assessed with a crack width of 0.5 mm. 7.13.1 Purpose—These reliability tests are used to assess the sensitivity of the anchor system installed in low-strength concrete to a wide crack in the concrete passing through the anchor location. 7.13.2 General test conditions—Perform tension tests in cracked concrete. Tests on adhesive anchors shall be confined tension tests. 7.13.3 Initiate the crack in the test member and install the anchor at the crack location so that the axis of the anchor lies approximately in the plane of the crack. Visually confirm the correct location of the crack in the drilled hole prior to installing the anchor in accordance with 4.5.2. Open the crack by the specified value Δw. Perform a confined tension test to failure with continuous measurement of load, displacement, and crack width. 7.14—Sensitivity to crack width—high-strength concrete Refer to Table 3.2, Test 4. R7.14 The effect of upper-bound service-condition cracking on the tension resistance of adhesive anchors in high-strength concrete is assessed with a crack width of 0.5 mm. This corresponds to a tolerable crack width for interior exposures. 7.14.1 Purpose—These reliability tests are used to assess the sensitivity of the anchor system installed in high-strength concrete to a wide crack in the concrete passing through the anchor location. 7.14.2 General test conditions—Perform tension tests in cracked concrete. Tests on adhesive anchors shall be confined tension tests. 7.14.3 Initiate the crack in the test member and install the anchor at the crack location so that the axis of the anchor lies approximately in the plane of the crack. Visually confirm the correct location of the crack in the drilled hole prior to installing the anchor in accordance with 4.5.2. Open the crack to the specified value Δw. Perform a confined tension test to failure with continuous measurement of load, displacement, and crack width. 7.15—Sensitivity to crack width cycling Refer to Table 3.2, Test 5, and Table 3.3, Test 3. R7.15 The crack-width cycling test simulates the effect of crack opening and closing as it might occur over the anchor service life due to diurnal temperature changes, settlement, or restraint of shrinkage and creep on the anchor tension resistance. The test consists of three parts: 1. Installation of the anchor in the crack and application of the static sustained load to the anchor. 2. Cycling of the crack width and monitoring of the anchor displacement. 3. Performance of a tension test to failure to measure the residual tension resistance of the tested anchor.


7.15.1 Purpose—These reliability tests are performed to evaluate the performance of anchors located in cracks whose width is cycled. 7.15.2 General test conditions— Perform crack cycling tests as unconfined tension tests in cracked concrete. Tests for residual capacity following crack cycling are confined tension tests performed in cracked concrete. 7.15.3 Prior to installing anchors in the test member, it shall be permitted to run opening and closing cycles as required to stabilize the relationship between crack width and applied load. Loading shall not exceed the elastic limit of the test member reinforcement. With the test member unloaded, install the anchor in a closed (hairline) crack that is sufficiently planar to ensure that the crack will approximately bisect the anchor location over the extent of the anchor loadtransfer zone. Visually verify the positioning of the anchor in the crack in accordance with 4.5.2.2. Measure the crack width in accordance with 4.8. After installation of the anchor but before the anchor is loaded, subject the test member to loading as required to open the crack width by Δw1 = 0.3 mm, where Δw1 is additive to the initial width of the crack after installation of the anchor but before loading of the anchor. Following application of load to the anchor sufficient to remove any slack in the loading mechanism, begin recording the anchor displacement, and increase the tension load on the anchor to Nw as given by Eq. (7-1). Apply the load in accordance with 4.7.2.2, unconfined. f c, test n N w = 0.3N k, i  ----------------  f c, test, 2

N

(7-1)

where = an anchor assessed in accordance with Table 3.2— Nk,i characteristic resistance as determined from reference service-condition tests in low-strength cracked concrete per Table 3.2, Test 11c, N; = an anchor assessed in accordance with Table 3.3— 25 percent of the characteristic resistance from reference service-condition tests in low-strength uncracked concrete per Table 3.3, Test 8a, N; fc,test = concrete compressive strength as measured at the time of testing, MPa; fc,test,2 = concrete compressive strength corresponding to the tests used to establish Nk,i , MPa; and n = normalization exponent determined in accordance with 10.2. While maintaining the static load on the anchor within 5 percent of Nw, cyclically load the test member as required to cause the crack width to alternate continuously between Δw1 (0.3 mm) and the lower crack width limit Δw2 (0.1 mm), where Δw2 is additive to the initial width of the crack as measured after installation of the anchor but prior to loading of the anchor. Open and close the crack 1000 times at a maximum frequency of approximately 0.2 Hz. During crack cycling, adjustment of the force required to maintain the crack opening width Δw1 constant shall be permitted. Hold the minimum load applied to the test member constant

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Fig. 7.1—Crack-width requirements for crack cycling. during the crack cycling portion of the test. The crack opening width Δw2 shall be permitted to increase (Fig. 7.1); however, the difference Δw1 – Δw2 shall be not less than 0.1 mm for the duration of the crack cycling portion of the test. During the test, adjust the amplitude of the load applied to the test member as required to maintain a minimum differential Δw1 – Δw2 of 0.1 mm. This may result in an increase in the crack width Δw1 beyond 0.3 mm for part of the crack cycling portion of the test. R7.15.3 The crack width is dependent, in part, on the bond stress developed by the embedded reinforcement on each side of the crack. Running opening and closing cycles serves to stabilize the bond stresses at a constant level and permits control of the crack width via application of a defined external load. Equation (7-1) provides a load level Nw on the anchor that is consistent with the load on headed anchors corresponding to the threshold displacements established for this test. Where these threshold displacements are exceeded in the test, the load Nw is reduced to a level that does not generate displacements in excess of the threshold values. Crack closing is accomplished with the embedded reinforcement and may be influenced by slippage of the anchor in the crack. It is not intended that crack closure should be controlled externally, for example, with a hydraulic cylinder. 7.15.3.1 Measure the load-displacement relationship up to load Nw. At load Nw, measure the displacements of the anchor and the crack-opening widths Δw1 and Δw2, either continuously or at least after 1, 2, 5, 10, 20, 50, 100, 200, 500, and 1000 cycles of crack opening and closing. 7.15.4 Following completion of the crack cycling portion of the test, unload the anchor, record the anchor displacement, open the crack width to Δw = 0.3 mm and perform a tension test of the anchor to failure with continuous measurement of load and displacement. 7.16—Sensitivity to freezing and thawing Refer to Table 3.1, Test 3; Table 3.2, Test 6; and Table 3.3, Test 4. R7.16 The test for sensitivity to freezing and thawing is intended to simulate in-service temperature fluctuations that the anchor might be subjected to during its service life. 7.16.1 Purpose—These reliability tests are performed to evaluate the performance of anchors under freezing-andthawing conditions.

30


7.16.2 General test conditions—Perform sustained tension tests in uncracked concrete followed by confined tension tests to failure. 7.16.3 The test member shall consist of a cube or cylinder with side length (or diameter) of 200 mm ≤ lside ≤ 300 mm for anchor diameters M12 to M16. For anchor diameters greater than 16 mm, the test member shall have a side length 15d ≤ lside ≤ 25d. Dimensions of the test member shall be chosen to avoid splitting the test member during the test conduct. Freezing-and-thawing-resistant concrete shall be permitted. Restraint of the test member as required to prevent splitting shall be permitted. Where such restraint is used (for example, steel cylinder), dimensions of the specimen may be reduced. 7.16.3.1 Install and cure anchors at standard temperature. 7.16.3.2 Cover the top surface of the test member within a minimum 75 mm radius from the center of the test anchor, with potable water maintaining a minimum of 13 mm depth throughout the test. Seal all other exposed surfaces to prevent evaporation of water. Load the anchor with a constant tension load Nsust,ft given by Eq. (7-2), to be maintained throughout the test. f c, test  n N sust, ft = 0.55N o,i  -------------- f c, test, i

N

(7-2)

where = mean tension capacity as determined from reference No,i service-condition tests in high-strength concrete as follows: Table 3.1, Test 7b; Table 3.2, Test 11b; or Table 3.3, Test 8b whereby results that are less than 85 percent of the mean value shall be excluded from the determination of the mean (for example, the mean shall be recalculated with the remaining results, N) (refer also to 4.7.2.2); fc,test = concrete compressive strength as measured at the time of testing, MPa; fc,test,i = concrete compressive strength corresponding to the tests used to establish No,i, MPa; and n = normalization exponent determined in accordance with 10.2. 7.16.3.3 Carry out 50 freezing-and-thawing cycles. 1. Maintain load at Nsust,ft throughout the freezing-andthawing test. 2. Raise the temperature of the chamber within 1 hour to 20°C ± 2°C. 3. Maintain the chamber temperature at 20°C ± 2°C for an additional 7 hours. 4. Lower the temperature of the chamber to –20°C ± 2°C within 2 hours. 5. Maintain the chamber temperature at –20°C ± 2°C for an additional 14 hours. 7.16.3.4 Measure the displacements during the temperature cycles. 7.16.3.5 If the test is interrupted, the samples shall always be stored at a temperature of –20°C ± 2°C between cycles. 7.16.3.6 After the completion of 50 cycles, conduct a confined tension test to failure at standard temperature.

7.17—Sensitivity to sustained loading at standard and maximum long-term temperature Refer to Table 3.1, Test 4; Table 3.2, Test 7; and Table 3.3, Test 5. R7.17 The sustained load, or creep test, is conducted to establish the creep behavior of the adhesive anchor system over its service life. Tests are performed at standard temperature of 23°C ± 4°C, and at long-term elevated temperature. The long-term elevated temperature corresponds to the temperature category as per Table 8.1. 7.17.1 Purpose—These reliability tests are performed to evaluate the performance of anchors under sustained loads at standard temperature and maximum long-term temperature. 7.17.2 General test conditions 7.17.2.1 Perform sustained tension tests in uncracked concrete, followed by confined tension tests to failure. 7.17.2.2 Install and cure anchors at standard temperature. 7.17.2.3 Conduct tests at standard and long-term test temperatures corresponding to the desired temperature categories in accordance with Table 8.1. If tests at the long-term test temperature are performed with Nsust in accordance with Eq. (7-3), unreduced by the factor αlt and extrapolated to 50 years, and compared to the limiting displacement at loss of adhesion derived from tests at standard temperature, the tests at standard temperature are permitted to be omitted (10.11.3). 7.17.2.4 Temperature control shall be maintained via thermocouples in the concrete test member. Embed thermocouples a maximum of 115 mm from the surface of the concrete into which the anchors are to be installed. Distance from the outer perimeter of the installed anchor and thermocouple shall not exceed 10 mm. The thermocouples shall be either cast in the concrete or positioned in holes drilled in the cured test member. Drilled holes for thermocouples shall have a maximum nominal diameter of 13 mm and shall be sealed in such a manner that the temperature readings reflect the concrete temperature. The exception to this is that thermocouples are not required if it can be experimentally demonstrated that the test procedure will consistently produce test member temperatures in accordance with the target temperatures. The test procedure will include monitoring of test chamber temperature at maximum 1-hour intervals. 7.17.2.5 Each test shall have a minimum duration of 42 days. 7.17.3 Tests at standard temperature 7.17.3.1 After the curing period has elapsed, apply a tension preload to the anchor prior to zeroing displacement readings not to exceed 5 percent of Nsust,lt or 1300 N, then increase the load on the anchor to a constant tension load Nsust,lt as given by Eq. (7-3). The load shall be applied using an unconfined test setup as shown in 4.4 or a confined test setup as shown in Fig. 4.5. After the load has been applied, adjust the temperature of the test member until the temperature, as recorded by the embedded thermocouples, is stabilized at the target temperature. f c, test  n N sust, lt = 0.55N o, i  -------------- f c, test, i

N

(7-3)


where No,i = mean tension capacity as determined from reference service-condition tests in low-strength concrete as follows: Table 3.1, Test 7a; Table 3.2, Test 11a; or Table 3.3, Test 8a whereby results that are less than 85 percent of the mean value shall be excluded from the determination of the mean, that is, the mean shall be recalculated with the remaining results, N (refer also to 4.7.2.2); fc,test = concrete compressive strength as measured at the time of testing, MPa; fc,test,i = concrete compressive strength corresponding to the tests used to establish No,i, MPa; and n = normalization exponent determined in accordance with 10.2. 7.17.3.2 Maintain the load at Nsust,lt and maintain the temperature at the target temperature. 7.17.3.3 Record anchor displacement for the test duration. The frequency of monitoring displacements shall be chosen to demonstrate the anchor characteristics. As displacements are greatest in the early stages, monitoring frequency should be high initially, but reduced over time. As an example, the following monitoring schedule would be acceptable: a) During the first hour—every 10 minutes b) During the next 6 hours—every hour c) During the next 10 days—every day d) Thereafter—every 5 to 10 days 7.17.3.4 Temperatures in the test chamber may vary by ±6°C due to day/night and seasonal effects, but the required test chamber temperature shall be achieved as an average over the test period. Record the concrete test member temperature at maximum 1-hour intervals. If thermocouples are not used in accordance with 7.17.2.4, record the temperature in the test chamber at maximum 1-hour intervals. 7.17.3.5 Alternatively, the concrete test member temperature shall be recorded at maximum 24-hour intervals provided the temperature of the conditioning chamber necessary to maintain the target test member temperature is recorded at maximum 1-hour intervals. 7.17.3.6 If the concrete test member temperature falls below the minimum target temperature, including tolerances, for more than 24 hours, extend the test duration by the length of time the temperature was below the target minimum. 7.17.3.7 At the conclusion of the sustained loading portion of the test, conduct a confined tension test to failure at standard temperature with continuous measurement of load and displacement. 7.17.4 Tests at long-term elevated temperature 7.17.4.1 It is required to perform the tests in a concrete test member made from the same concrete batch as the test member used for the tests at elevated short-term temperature. 7.17.4.2 After the curing period has elapsed, increase the temperature of the test member until the temperature, as recorded by the embedded thermocouples, is stabilized at the target temperature. Raise the temperature of the test chamber to the maximum long-term test temperature (either Category A or B according to Table 8.1) at a rate of approximately 20°C per hour. Apply a tension preload not exceeding 5 percent of

31

Nsust,lt or 1300 N to the anchor prior to zeroing displacement readings. Then increase the load on the anchor to a constant tension load Nsust,lt as given by Eq. (7-3) multiplied by αlt as determined in accordance with Eq. (10-26). 7.17.4.3 Maintain load Nsust,lt and maintain temperature at the maximum long-term test temperature. For the frequency of displacement monitoring, refer to 7.17.3. At the long-term test temperature, the temperature in the test chamber may vary by ±3°C due to day/night and seasonal effects, but the required test chamber temperature shall be achieved as an average over the test period. 7.17.4.4 To check the remaining load capacity after the sustained load test, unload the anchor and carry out a confined tension test at the maximum long-term test temperature. 7.18—Sensitivity to installation direction Refer to Table 3.1, Test 5; Table 3.2, Test 8; and Table 3.3, Test 6. R7.18 The majority of ACI 355.4M tests are performed on anchors installed in the downward position. Where anchors are to be installed in other orientations, such as horizontal and overhead, tests are required to validate the performance of the adhesive anchor system for these orientations. These tests are intended to ensure the MPII is adequate to describe the necessary installation steps, the adhesive anchor system is appropriate for installation in the tested orientation, and the bond strength has been correctly assessed for anchors installed in the tested orientation. Factors of particular importance in the assessment include completely filling the hole with adhesive, avoiding excessive adhesive run-out during the installation process, and preventing anchor element sag during adhesive cure. Because of the possibility for run-out of adhesive during overhead installations, particular care should be exercised to prevent skin or eye exposure, and all precautions indicated by the MSDS for the product should be exercised. For adhesive anchor systems not designed for other than down-hole installation, these tests may be omitted. To avoid accidental misuse of such products, however, it is necessary to provide a standardized warning label on the product (for example, cartridge and foil pack) and on the packaging indicating restrictions on use (Fig. 7.2). 7.18.1 Purpose—These optional reliability tests are performed to evaluate the performance of adhesive anchors installed horizontally and overhead, that is, vertically up. 7.18.2 General test conditions—Perform confined tension tests in uncracked concrete. Conduct tests on all-thread anchors that have been installed in accordance with the MPII. 7.18.3 Perform separate test series with anchors installed horizontally and overhead. Perform tension tests to failure with continuous measurement of load and displacement. Install and cure anchors at the minimum and maximum installation temperatures for concrete and adhesive included in the MPII for downhole installation. Perform tension tests at standard temperature. 7.18.3.1 Anchor installation used for testing shall be reviewed for effectiveness. A procedure for verifying the effectiveness of overhead installation procedures using blind injection into a clear tube of equivalent diameter and length is

32


Fig. 7.2—Required labeling for products not tested for sensitivity to installation orientation.

Fig. 7.4—Torque test setup. 7.19.3 Apply increasing torque and record the torque and corresponding induced tension in the anchor bolt. The washer shall not turn during the application of torque. CHAPTER 8—SERVICE-CONDITION TESTS 8.1—Purpose The purpose of the service-condition tests is to determine the basic data required to predict the performance of the anchor under service conditions. R8.1 Service-condition tests establish the general strength data for the anchor system in uncracked and cracked concrete and under various temperature and environmental exposure conditions, as well as in conjunction with seismic loading. Fig. 7.3—Procedure to verify effectiveness of adhesive injection method. shown in Fig. 7.3. The procedure used shall enable the evaluation of the installation procedure as described in 10.12. 7.19—Torque test Refer to Table 3.1, Test 6; Table 3.2, Test 9; and Table 3.3, Test 7. R7.19 Torque tests establish a tightening torque that produces a clamping force to be applied to the connection through the adhesive anchor, but not too high of a clamping force so that the bond between the adhesive and concrete or between the anchor rod and the adhesive is broken. For anchor elements that do not require the application of torque, such as deformed reinforcing bar dowels, these tests may be omitted. 7.19.1 Purpose—These reliability tests are used to establish the maximum level of torque that can be applied to the installed anchor without inducing tension yield of the anchor element or damaging the adhesive bond. 7.19.2 General test conditions—Figure 7.4 shows the test setup. The fixture shall contain all elements shown. The double-sided abrasive paper shall have sufficient roughness to prevent rotation of the washer relative to the test fixture during the application of torque. Other methods of preventing rotation of the washer shall be permitted, provided it can be shown they do not affect the anchor performance.

8.2—Required tests Required service-condition tests are given in Table 3.1 for adhesive anchors qualified for use in uncracked concrete only and in Table 3.2 or 3.3 for adhesive anchors qualified for use in both uncracked and cracked concrete. Test requirements for adhesive anchors assessed to resist seismic loads are defined in Table 3.2. R8.2 Anchors to be qualified for use in cracked concrete are installed in hairline cracks, which are then opened to a crack width w of 0.3 mm before anchor loading. This crack width is consistent with the expected response of reinforced concrete structures under sustained load. 8.3—Conduct of tests R8.3 Service-condition tests are to be performed on anchors installed in accordance with the MPII. 8.3.1 Prepare test members, install anchors, and test in accordance with Chapter 4 unless otherwise noted. 8.3.2 Perform tests in dry concrete. 8.3.3 Perform tests with air, concrete, and anchor at standard temperature unless otherwise noted. 8.4—Tension tests in uncracked and cracked concrete Refer to Table 3.1, Tests 7a and 7b; Table 3.2, Tests 11a, 11b, 11c, and 11d; and Table 3.3, Tests 8a and 8b. R8.4 Tests are conducted in low- and high-strength concrete to establish the characteristic limiting bond stress.


Depending on the characteristics of the adhesive and the embedment depths for which the system is to be assessed, it may be necessary to take special measures to achieve bond failures in these tests (refer to 4.7). The use of confined tests is permitted under certain conditions and can enable the use of reference tests for establishing characteristic limiting bond stress values. 8.4.1 Purpose—These tests are used to establish the bond resistance of the anchor system. 8.4.2 Conduct of tests—Perform unconfined servicecondition tension tests in accordance with Section 4.7 in both low- and high-strength concrete. 8.4.2.1 It shall be permitted to perform the servicecondition tension tests described in Table 3.1, Tests 7a and 7b; Table 3.2, Tests 11a through 11d; and Table 3.3, Tests 8a and 8b as confined tests if the evaluation for τk,cr is performed in accordance with 10.4.5.3.3. 8.5—Tension tests at elevated temperature Refer to Table 3.1, Test 8a; Table 3.2, Test 12a; and Table 3.3, Test 9a. R8.5 Tension tests establish the anchor performance at concrete temperatures elevated above standard temperature for long and short durations (2.2—elevated concrete temperature). Temperature Category A provides a standard approach that assumes a potential long-term elevated temperature consistent with hot climate exposures and a short-term temperature reflective of diurnal cycling in such climates for a given sun exposure duration and concrete mass. Typical sources of elevated concrete temperature are anticipated, with the exception of heat of hydration in earlyage concrete, extreme elevated temperature (for example, boiler rooms), and exposure to nuclear radiation in containment structure. Temperature Category B establishes the same long-term temperature as temperature Category A. This temperature is relevant for testing to establish response to sustained load. The short-term temperature remains openended, however, and the response of the adhesive anchor to intermediate levels of elevated concrete temperature is established. Products may be tested and assessed for either or both categories under this standard. 8.5.1 Purpose—These service-condition tests are used to assess the sensitivity of the adhesive material to applications in concrete with elevated temperatures that can occur over short periods of time, that is, short-term test temperatures, as well as elevated temperatures that may occur over more extended periods, that is, long-term test temperatures. 8.5.2 General test conditions—Conduct static tension tests at long-term and short-term concrete temperatures corresponding to the desired temperature category (Table 8.1). It shall be permitted to obtain qualification at multiple temperature categories. 8.5.2.1 Conduct confined tension tests in uncracked concrete. 8.5.2.2 Maintain temperature control with thermocouples in accordance with 7.17.2.4. Alternatively, it shall be permitted to correlate the chamber temperature with the test member

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Table 8.1—Required temperatures for testing at long- and short-term elevated concrete temperatures* Temperature Long-term temperature, Tlt , °C category

Short-term temperature, Tst , °C

A

43

80

B

≥ 43

≥ Tlt + 11

*

All test temperatures have a minus tolerance of 0 degrees.

internal temperature by separate investigations and control the chamber temperature for the elevated temperature tests. 8.5.2.3 Qualify anchors for one or both of the temperature categories given in Table 8.1. Install and test a minimum of five anchors at each temperature data point. For Temperature Category A, perform tests at the short- and long-term test temperatures. For Temperature Category B, perform tests on anchors—at standard temperature, at the long-term and short-term test temperatures, and at a minimum of two intermediate temperatures between the long-term and shortterm temperatures with a maximum increment of 20°C. If the difference between the standard temperature and the selected short-term test temperature is less than 20°C, then testing at intermediate temperatures is not required. 8.5.2.4 Install and cure all anchors at standard temperature. Following the recommended cure period, heat and maintain the test members at the desired temperature for a minimum of 24 hours. Remove each test member from the heating chamber and conduct a confined tension test to failure with continuous measurement of load and displacement before the temperature of the test member falls below the temperature listed in Table 8.1. 8.6—Tension tests with decreased installation temperature Refer to Table 3.1, Test 8b; Table 3.2, Test 12b; and Table 3.3, Test 9b. R8.6 These tests establish the suitability of the adhesive anchor system for installation in concrete at lower-thanstandard temperatures. All adhesive anchor systems qualified for installation in concrete temperatures below 10°C are required to be installed and tested at the target concrete temperature. When the target temperature for the system to be qualified falls below 5°C, additional tests are required to assess the effect of rising concrete temperatures on the anchor response. The rate of temperature rise is intended to be consistent with sun exposure. Follow special procedures where the MPII includes them for low-temperature installation conditions. Where preheating of adhesive cartridges to reduce viscosity and facilitate adhesive flow is specified in the MPII, observations should be made to determine whether this results in retarded cure, lowering of the glass-transition temperature, and impaired resistance to creep. 8.6.1 Purpose—These service-condition tests are used to assess the sensitivity of adhesive material to installation in concrete below the standard temperature. 8.6.2 General test conditions—Perform confined tension tests in uncracked concrete for anchors to be installed in

34


concrete having a temperature less than 10°C. Prior to installation, condition the anchor rod and test member to the lowest installation temperature and maintain it for a minimum of 24 hours. Install anchors in concrete test members and allow them to cure at the stabilized temperature according to the MPII. Remove the test member from the cooling chamber and tension test the anchors immediately to assure the test members reasonably remains at the conditioned temperature. A thermocouple inserted into the test member may be used to confirm the temperature at the time of testing. 8.6.2.1 When the adhesives are recommended for installation in concrete temperatures below 5°C in addition to the tests described in 8.6.2, perform the following test: a) Install and test a minimum of five anchors per the MPII. Prior to installation, condition the anchor rod and test member to the target temperature and maintain that temperature for a minimum of 24 hours. b) Install the anchors in accordance with the MPII and allow them to cure at the stabilized target temperature recommended by the MPII. c) Apply a constant tension load Nsust,ft as given by Eq. (7-2). Raise the temperature of the test chamber at a constant rate to standard temperature for 72 to 96 hours while monitoring the displacement response for each anchor. A thermocouple inserted into the test member may be used to confirm test member temperatures during the test. Once the test member attains standard temperature, conduct a confined tension test to failure with continuous measurement of load and displacement. 8.7—Establishment of cure time at standard temperature Refer to Table 3.1, Test 8c; Table 3.2, Test 12c; and Table 3.3, Test 9c. R8.7 Cure time of most adhesive compounds is inversely proportional to temperature. Where cure times are provided for temperature ranges that overlap the standard temperature range, a temperature should be selected that corresponds to the lower end of the range. 8.7.1 Purpose—These service-condition tests are used to establish the minimum curing time of the adhesive material for the anchor to achieve full tension capacity. 8.7.2 General test conditions—Perform confined tension tests in uncracked concrete. Tests are conducted on anchors installed in accordance with the MPII at standard temperature. The anchors are allowed to cure for the minimum curing time. Tests are also conducted on anchors installed in the same way and allowed to cure for the time specified in the MPII plus an additional 24 hours. 8.8—Durability assessment Refer to Table 3.1, Tests 9a and 9b; Table 3.2, Tests 13a and 13b; and Table 3.3, Tests 10a and 10b. R8.8 Durability tests are intended to assess the response of the adhesive to aggressive exposure conditions. The slice test, where a thin slice of the installed anchor is exposed to a specific environmental condition and then tested for

residual bond strength in the punch test apparatus, provides for a relatively uniform and conservative assessment of the exposure condition by assuring the entire bond layer is subjected to the aggressive compound. Care must be taken in preparation of the slices and punch testing to ensure reliable results. An austenitic stainless steel anchor element of sufficient resistance should be used in the sulfur dioxide tests to avoid steel failure. It does not capture all possible environmental exposures deleterious to anchor performance. The two exposure conditions—alkalinity and sulfur—are considered two of the most common and aggressive and, therefore, used as the baseline classification of anchor use. 8.8.1 Purpose—These service-condition tests are used to assess the response of the adhesive material to attack by environmental aggressors. Verify the durability of the adhesive material with slice tests. With slice tests, the sensitivity of installed anchors to different environmental exposures can be assessed. The test for exposure to high alkalinity (8.8.2.2.1) is required. The test for exposure to sulfur dioxide (8.2.2.2.2) is optional. 8.8.2 General test conditions—Conduct tests on 13 mm diameter all-thread anchors or the smallest nominal diameter if it is larger than 13 mm. Embed anchors in cylindrical concrete test members having a minimum diameter of 150 mm. Cast the concrete test members in lengths of steel or plastic pipe having a wall thickness as required to prevent slice splitting during punch testing. All test members shall originate from the same concrete batch. Install anchors along the central axis of the concrete test members according to the MPII. For tests in sulfur dioxide, fabricate the anchor element from austenitic stainless steel. After curing the adhesive, concrete cylinders in which the anchors are installed shall be sawn with a diamond saw into 30 mm ± 3 mm thick slices so the resulting slices are undamaged. Slices shall be oriented perpendicular to the anchor axis and consist of the concrete, adhesive material, and anchor element. Discard the top and bottom slices. Prepare a minimum of 10 slices for each environmental exposure to be investigated and 10 reference slices subjected to standard climate conditions. 8.8.2.1 Storage of reference slices—Store the slices under normal climate conditions (dry/standard temperature/relative humidity 50 ± 5%) for 2000 hours. 8.8.2.2 Storage of slices under aggressive environmental exposure—Store 10 slices each under the following environmental exposures. 8.8.2.2.1 High alkalinity— Store slices under standard climate conditions in a container filled with an alkaline fluid (pH = 13.2). All slices shall be completely covered for 2000 hours. Produce the alkaline fluid by mixing water with potassium hydroxide (KOH) powder or tablets until the pH value of 13.2 is reached. Maintain a mean alkalinity value of pH = 13.2 ± 0.2 during storage. If the measured alkalinity falls below 13.0, extend the test duration by the total length of time during which the pH value was less than 13.0. The length of time the pH was less than 13.0 shall not be included in the calculation of the mean alkalinity value. Monitor the pH value on a daily basis.


8.8.2.2.2 Sulfur dioxide—Perform tests according to EN ISO 6988 (Kesternich Test); the theoretical sulfur dioxide concentration, however, shall be 0.67 percent at the beginning of a cycle, corresponding to 2 dm3 of SO2 for a test chamber volume of 300 dm3. Perform at least 80 cycles. 8.8.3 Punch tests—Within 24 hours after removal of the specimen from storage, measure the thickness of the slices and test them in a test apparatus that permits the metal, that is, the anchor element part of the slice, to be punched through the slice while restraining the surrounding concrete (Fig. 8.1). The loading punch shall act centrally on the metal element. The peak load for each test shall be recorded. Discard results from slices that split during the punch test. Evaluate the bond stress τdur,i for each punch test using Eq. (8-1). N u, i τ dur, i = -------------- MPa πd a h sl where hsl da Nu,i

35

Fig. 8.1—Punch test.

(8-1)

= = =

measured thickness of slice i, mm; anchor diameter, mm; and measured axial load corresponding to failure of slice i, N. R8.8.3 Slices removed from storage should be tested as soon as possible to avoid the potential effects of specimen drying on the measured bond strength.

8.9—Verification of full concrete capacity in a corner Refer to Table 3.1, Test 10; Table 3.2, Test 14; and Table 3.3, Test 11. R8.9 The concrete capacity design method assumes that maximum concrete breakout or bond capacity is reached at edge distances equal to or greater than cac. To check this assumption for a specific anchor system, tests are performed with single anchors in a corner with ca1 = ca2 = cac. This edge distance represents the critical edge distance at which there is no edge influence on the tensile capacity of the anchor as governed by concrete failure. The tests are performed in concrete members having the smallest thickness hmin for which the manufacturer wishes to qualify the anchor. These tests permit the selection of product-specific values for cac that, in conjunction with some value of hmin, will allow anchor installation without damage in the form of splitting cracks to the concrete. There can be more than one combination of these values. 8.9.1 Purpose—This test is performed to determine the critical edge distance cac in test members with the minimum specified thickness for that anchor. 8.9.2 General test conditions—Perform tests on single anchors in uncracked, low-strength concrete at a corner with equal edge distances of cac, and test member thickness hmin (Fig. 8.2). 8.10—Determination of minimum spacing and edge distance to preclude splitting Refer to Table 3.1, Test 11; Table 3.2, Test 15; and Table 3.3, Test 12.

Fig. 8.2—Corner test.

R8.10 Tests are performed with two anchors installed parallel to an edge with the minimum edge and spacing distances and in a test member having the smallest thickness for which the manufacturer wishes to qualify the anchor. Minimum values for edge distance and anchor spacing are given in ACI 318M, Appendix D. These tests permit the selection of product-specific values for cmin and smin that, in conjunction with some value of hmin , will allow anchor installation without damage in the form of splitting cracks to the concrete. There can be more than one combination of these three minimum values. While the application of torque is not required to set normal adhesive anchor systems, most MPIIs specify a maximum torque value for the clamp attachment to the concrete. Use of an elevated torque value (1.7Tinst) is intended to compensate for possible inaccuracies in torque wrenches on site. For conditions in which torque is not applied to the anchor, the minimum edge distance is governed by the drilling process used to install the adhesive anchor. 8.10.1 Purpose—This test is performed to verify for the smin and cmin requested by the manufacturer that the concrete will not experience splitting failure during installation and the required tension capacity is achieved.

36


8.10.2 General test conditions; test anchors in uncracked, low-strength concrete—Install two anchors at the minimum spacing smin and the minimum edge distance cmin in test members with the minimum thickness hmin to be reported for the anchor. Place the two anchors in a line parallel to the edge of a concrete test element at a distance of at least 3hef from other groups. Select smin, cmin, and hmin depending on anchor characteristics. 8.10.2.1 Separate bearing plates shall be permitted to be used for each anchor to simplify the detection of concrete cracking. The distance to the edge of the bearing plate from the centerline of the corresponding anchor shall be three times the diameter da of the anchor being tested. 8.10.2.2 Calculate the expected mean tension failure load corresponding to the edge distance and spacing of the anchor group to be tested considering the service-condition tests and effects of reduced spacing and edge distance. If the average prestressing force corresponding to 1.7Tinst exceeds the calculated mean tension failure load of the anchor group in uncracked concrete, perform a torque test in accordance with 8.10.2.3. Otherwise, perform a load test in accordance with 8.10.2.4. 8.10.2.3 Torque test—Torque the anchors alternately in increments of 0.2Tinst. After each increment, inspect the concrete surface for cracks. Stop the test when splitting or steel failure prevents the torque from being increased further. For each test, simultaneously record the torque at first formation of a hairline crack at one or both anchors and the maximum torque that can be applied to the anchors. 8.10.2.4 Load test—Install anchors according to the MPII using the minimum specified spacing and edge distances. Load the anchor group in tension to failure as an unconfined test. 8.11—Tests to determine shear capacity of anchor elements with nonuniform cross section Refer to Table 3.1, Test 12; Table 3.2, Test 16; and Table 3.3, Test 13. 8.11.1 Purpose—This test is performed to evaluate the shear capacity of anchors as governed by element shear failure in situations where the shear capacity cannot be reliably calculated. R8.11.1 Where the cross-sectional area of the anchor shear plane is less than a threaded section of the same nominal diameter within five anchor diameters of the shear plane, the shear capacity may be affected by the reduced section. Additionally, shallow anchors that exhibit pullout failure in unconfined tension tests may exhibit shear strengths away from edges that are below those predicted by ACI 318M, Appendix D. Tests shall be performed to establish the appropriate shear capacity in these cases. For anchors assessed for use in cracked concrete and resisting seismic loads, it may be advantageous to establish the reference shear capacity of the anchor system in cracked concrete. 8.11.2 General test conditions—Perform shear tests in uncracked concrete away from edges in accordance with ASTM E488.

1. Test anchor elements having a cross-sectional area that is less than a threaded bolt of the same nominal diameter as the anchor within five anchor diameters of the shear failure plane. 2. Test anchors at hef = hef, min and at hef = 2hef, min for anchor diameters that exhibit pullout failure in unconfined tension tests at hef = hef, min where hef, min ≤ 8da. 8.11.3 For anchors evaluated according to Table 3.2, at the manufacturer’s option, shear tests shall be performed in cracked concrete with a crack width of 0.3 mm, with the shear load applied parallel to the crack. 8.12—Simulated seismic tension tests Refer to Table 3.2, Test 17. R8.12 Simulated seismic tests are intended to assess the anchor performance in cracked concrete conditions under cyclic loading. The crack width is assumed to be roughly 150 percent of the maximum crack width associated with elastic conditions, with the maximum level of cyclic loading approximately twice the service load level under nonseismic conditions. These tests are not intended to simulate all possible loading conditions that may occur in an earthquake or intended to represent the degree of cracking that might occur in plastic hinge regions of reinforced concrete structures. 8.12.1 Purpose—These optional tests are intended to evaluate the performance of anchors in seismic tension, including the effects of cracks, but without edge effects. Qualification for seismic loading shall only be considered in the context of a cracked concrete test program in accordance with Table 3.2. 8.12.2 General test conditions—Test each anchor diameter at embedments as specified in Table 3.2. Install the anchor in a closed crack in accordance with 4.8. If no torque is specified by the MPII, finger-tighten the anchor prior to testing. Open the crack by Δw = 0.5 mm, where Δw is additive to the width of the closed hairline crack after anchor installation. Subject the anchors to the sinusoidal tension loads specified in Table 8.2 and Fig. 8.3 with a cycling frequency between 0.1 and 2 Hz, whereby Neq is given by Eq. (8-2), Nm is given by Eq. (8-3), and Ni is given by Eq. (8-4). f c, test  n N N eq = 0.5N o, i  --------------- f c, test, 2 

(8-2)

where = mean tension capacity from reference serviceNo,i condition tension tests in low-strength cracked concrete (Table 3.2, Test 11c), N; fc,test = compressive strength of concrete used at time of testing, MPa; fc,test,2 = concrete compressive strength corresponding to the tests used to establish No,i , MPa; and n = normalization exponent determined in accordance with 10.2. N eq - N N m = ------2

(8-3)


37

Fig. 8.3—Required load history for simulated seismic tension test.

Fig. 8.4—Required load history for simulated seismic shear test.

Table 8.2—Required loading history for simulated seismic tension test

Table 8.3—Required loading history for simulated seismic shear test

Load level

Neq

Ni

Nm

Load level

Number of cycles

10

30

100

Number of cycles

N eq + N m N i = --------------------- N 2

(8-4)

8.12.2.1 Record the crack width, anchor displacement, and applied tension load in accordance with 4.8. Following completion of the simulated seismic-tension cycles, open the crack to a width not less than the crack opening width as measured at the end of the cyclic test and load the anchor in tension to failure. Record the maximum tension load, that is, residual tension capacity; the corresponding displacement; and plot the load-displacement response. 8.13—Simulated seismic shear tests Refer to Table 3.2, Test 18. R8.13 Simulated seismic shear tests are performed in cracks that are parallel to the load direction. Load cycling may be conducted at a relatively low frequency because the loading rate has not been determined to be a significant factor in anchor performance. The use of a ramped loading function through the zero point of the cyclic load may be advantageous for operation of the testing apparatus. 8.13.1 Purpose—These optional tests are intended to evaluate the performance of anchors subjected to seismic shear loads, including the effects of concrete cracking. Qualification for seismic loading shall only be considered in the context of a cracked concrete test program as given in Table 3.2. 8.13.2 General test conditions—Test each anchor diameter at embedments as specified in Table 3.2. Install the anchor in a closed crack in accordance with 4.8. If no torque is specified by the MPII, finger-tighten the anchor prior to testing. Test internally-threaded anchors with the bolt specified by the manufacturer and report the bolt type (refer to Table 11.1 or Table 11.2 for forms). Open the crack by Δw = 0.5 mm, where Δw is additive to the width of the initial hairline crack after anchor installation. Subject the anchors to the sinusoidal shear loads specified in Table 8.3 and Fig. 8.4, with the shear load applied

±Veq

±Vi

±Vm

10

30

100

parallel to the direction of the crack, whereby Veq is given by Eq. (8-5), Vm is given by Eq. (8-6), and Vi is given by Eq. (8-7). f c, test V eq = 0.5V o, i ---------------f c, test, 2 where Vo,i

=

fut,test

=

fut,test,2

=

N

(8-5)

mean shear capacity of anchors from reference service-condition tests in uncracked, lowstrength concrete (Table 3.2, Test 16), N; specified ultimate tensile strength of steel anchor elements used in seismic tests, MPa and measured ultimate tensile strength of steel anchor elements used in reference servicecondition tests, MPa. V eq V m = ------2 V eq + V m V i = -------------------2

N

(8-6)

N

(8-7)

8.13.2.1 If the service-condition shear tests have not been performed, Veq shall be permitted to be evaluated in accordance with Eq. (8-8). Veq = 0.35Ase fut,test N

(8-8)

8.13.2.2 The frequency of loading shall be between 0.1 and 2 Hz. To reduce the potential for uncontrolled slip during load reversal, the alternating shear loading shall be permitted to be approximated by the application of two half-sinusoidal load cycles at the desired frequency connected by a reducedspeed ramped load, as shown in Fig. 8.5. 8.13.2.3 Record the crack width, anchor displacement, and applied shear load in accordance with 4.8. Plot the loaddisplacement history in the form of hysteresis loops.

38


Table 9.1—Materials for concrete round robin tests

Fig. 8.5—Permitted approximation of seismic shear cycle.

8.13.2.4 Following completion of the simulated seismicshear cycles, open the crack to a width not less than the crack opening width as measured at the end of the cyclic shear test and load the anchor parallel to the crack in shear to failure. Record the maximum shear load or residual shear capacity and the corresponding displacement, and plot the loaddisplacement response. CHAPTER 9—SUPPLEMENTAL TEST 9.1—Round-robin tests Refer to Table 3.1, Test 13; Table 3.2, Test 19; and Table 3.3, Test 14. R9.1 The relationship between concrete composition and adhesive anchor performance is not well understood. Anecdotal evidence indicates there may be a direct relationship between aggregate types used and bond strength. Roundrobin tests are intended to establish the consistency of bond properties of the tested system over a range of concrete mixture designs originating from various geographic regions. Two mixture designs—one without and one with fly ash as a cement replacement—are intended to provide a representative sample of concrete compositions in North America. 9.1.1 Purpose—These round-robin tests are performed to calibrate adhesive anchor test results for regional variations in concrete. 9.1.2 General test conditions—Perform round-robin tension tests on anchor diameters and embedments as specified in Table 3.1, 3.2, or 3.3. 9.1.3 Round-robin tension tests shall be performed by the primary testing laboratory and three additional independent laboratories (also known as secondary laboratories) accredited for testing adhesive anchors in accordance with Chapter 12. The three additional independent laboratories shall be selected by the primary testing laboratory and accredited for testing of anchors according to ASTM E488. 9.1.4 All round-robin tests shall be conducted with ASTM A193 B7 Unified National Coarse (UNC) threaded rod anchors. If steel failure occurs, the embedment depth shall be reduced for all round-robin tests. Anchor test specimens sampled in accordance with 4.2 shall be provided by the primary testing laboratory to the three additional laboratories. Where the primary laboratory uses data from more than one

Mixture design

Coarse aggregate

Fine aggregate

A

Normalweight

Normalweight ASTM C150 Type II cement

B

Normalweight

Normalweight

Cementitious material ASTM C150 Type II cement combined with 25% Class F fly ash conforming to ASTM C618

laboratory for the assessment of the service-condition tension capacity in low-strength concrete, each laboratory shall provide round-robin tests. 9.1.5 Each of the four laboratories performing round-robin tests shall be located in a different geographic region of North America, whereby the geographic regions shall be defined by time zone as follows: Region 1: Pacific Time Zone; Region 2: Mountain Time Zone; Region 3: Central Time Zone; and Region 4: Eastern and Atlantic Time Zones. Aggregates used for the concrete shall be representative of typical concrete production in each laboratory’s immediate geographic location. It shall be permitted, however, to transport specimens prepared by the regional laboratories in the different geographic regions to the primary testing laboratory for testing. 9.1.5.1 If the primary laboratory is located outside of North America, four secondary laboratories, each located in a different geographic region in North America, shall be selected by the primary laboratory and round-robin tests shall be provided by the secondary laboratories only. The aggregates used for the concrete shall be representative of typical production in each laboratory’s geographic location. 9.1.6 For the purpose of round-robin testing, each secondary laboratory shall cast unreinforced concrete test members 300 mm thick with minimum plan dimensions of 1.2 x 0.9 m from normalweight concrete using mixture designs formulated to achieve 21 ± 3.5 MPa at the time of testing. Mixture designs shall be in accordance with 4.3 and 9.1.6. Aggregates shall be in accordance with 4.3.2. Test member strength shall be confirmed based on field prepared and cured cylinders in accordance with 4.4.3.2. Concrete shall be produced from Mixture Designs A and B with materials in accordance with Table 9.1. 9.1.7 Install anchors in accordance with the MPII. Perform a minimum of five confined and five unconfined tension tests to failure on anchors in concrete produced in accordance with Mixture Design A and a minimum of five confined and five unconfined tension tests to failure in concrete produced in accordance with Mixture Design B. Perform tests in accordance with 4.7 within the concrete age interval of 28 to 56 days. Confined round-robin tests may be omitted, however, if Eq. (9-1) is fulfilled. k ≤ 10 where Nu k = ---------------------------1.5 h ef f c, test, i

(9-1)


Nu is the mean ultimate tension load in unconfined roundrobin tests, N. 9.2—Tests to determine minimum member thickness Refer to Table 3.1, Test 14; Table 3.2, Test 20; and Table 3.3, Test 15. R9.2 The determination of alternate minimum member thicknesses hmin is permitted through testing conducted in accordance with this section. Refer also to 8.9 and 8.10. 9.2.1 Purpose—These optional tests are performed to check the minimum member thickness hmin specified by the manufacturer. 9.2.2 General test conditions—Test anchor diameters and embedments as specified in Table 3.1, 3.2, or 3.3. 9.2.2.1 Perform a minimum of 10 installation tests for the maximum embedment depth hef associated with each anchor diameter to demonstrate that hole drilling and installation (for example, setting and torquing of the anchor) does not result in cracking or breakthrough of the concrete test member. A test shall consist of drilling the hole, setting the anchor, and inspecting the test member for visible concrete cracking or spalling. For the purpose of these tests, support the test member, that is, slab and beam, with a shear span length, which is the distance from anchor to support, not less than 1.5hef. Use drilling equipment and setting procedures that are representative of normal anchor installation as specified by the anchor manufacturer. 9.2.2.2 Instead of 9.2.2.1, tests in accordance with 8.9 and 8.10 shall be permitted to be conducted with the test member supported with a shear span length not less than 1.5hef. Drilling equipment and setting procedures shall be representative of normal anchor installation as specified by the manufacturer. Subsequent to drilling the holes and setting anchors, the balance of tests in accordance with 8.9 and 8.10 shall be permitted, conducted without supports. CHAPTER 10—ASSESSMENT OF ANCHORS 10.1—Analysis of data Analyze data according to the procedures of this chapter and report the results according to the requirements of Chapter 11. 10.2—Normalization of anchor capacities for measured concrete bond and steel strengths R10.2 Normalization to 17 MPa is based on the minimum concrete compressive strength permitted by ACI 318M. 10.2.1 Consider the failure type when reporting results and data and comparing anchor capacities of tests that require normalization to a specific or a common strength. 10.2.2 Normalize all test results to a concrete compressive strength of 17 MPa and report according to the requirements of Chapter 11, unless otherwise specified by this standard. 10.2.3 Concrete breakout, splitting, and pullout failure 10.2.3.1 Normalize test results for the influence of the concrete compressive strength in accordance with Eq. (10-1). f c, i  n F i = F u, test, x  -------------- f c, test, x 

N

(10-1)

where Fi

39

=

test result normalized to considered concrete strength i, N; Fu,test,x = test result from test series x, N; = concrete compressive strength corresponding fc,i to concrete to which the test result shall be normalized, MPa; fc,test,x = concrete compressive strength corresponding to concrete used for test series x, MPa; and n = 0.5 for concrete breakout and splitting failure or shall be determined from tests when failure under tension load is characterized by pullout or when tests are performed as confined tests. 10.2.4 Anchor element failure 10.2.4.1 Where failure is characterized by metal rupture, normalize the capacity for nominal anchor element material strength using Eq. (10-2). For steels conforming to a standard, the characteristic tensile strength shall be taken as the minimum specified tensile strength futa. f uta F u = F u, test, x ---------------f u, test, x where Fut Fu,test,x futa

= = =

fu,test,x

=

N

(10-2)

normalized test result, N; test result from test series x, N; specified steel tensile strength to which the test result shall be normalized, MPa; and measured steel tensile strength corresponding to anchors used for test series x, MPa.

10.3—Establishing characteristic values R10.3 Establishment of characteristic values is based on factors for one-sided tolerance limits for normal distributions. 10.3.1 Evaluate the characteristic value—for example, Nk , Np, Ns , and Vs—from the mean value and the associated coefficient of variation v using Eq. (10-3). Fk = Ftest,x(1 – K · νtest,x) where K

=

Fk Ftest,x νtest,x

= = =

(10-3)

tolerance factor corresponding to a 5 percent probability of nonexceedence with a confidence of 90 percent derived from a noncentral tdistribution for which the population standard deviation is unknown (values for specific samples sizes n are provided in Table 10.1); characteristic value (5 percent fractile), N; mean of test results for test series x, N; and coefficient of variation of the population sample corresponding to test series x, percent.

10.4—Assessment of characteristic tension capacity associated with concrete breakout and pullout 10.4.1 Adjustment for regional variations in concrete (Section 9.1) R10.4.1 Variations in adhesive anchor bond strength as determined from round-robin tests is reflected in the value of

40


Table 10.1—K values for 5 percent probability of nonexceedence with a confidence of 90 percent Number of tests n

K

Number of tests n

K

3

5.311

21

2.190

4

3.957

22

2.174

5

3.400

23

2.159

6

3.092

24

2.145

7

2.894

25

2.132

8

2.754

26

2.120

9

2.650

27

2.109

10

2.568

28

2.099

11

2.503

29

2.089

12

2.448

30

2.080

13

2.402

35

2.041

14

2.363

40

2.010

15

2.329

45

1.986

16

2.299

50

1.965

17

2.272

60

1.933

18

2.249

120

1.841

19

2.227

240

1.780

20

2.208

∞

1.645

α conc. Testing in conformance with round-robin testing requirements may result in significant scatter and adjustment of the characteristic bond stress from round-robin testing should be limited to cases where there is a clear trend. As such, a 5 percent tolerance on the ratio of the round-robin bond stress to the reference bond stress is included in the assessment. Where confined tests have been performed in accordance with Section 9.1.7, the value of α conc corresponding to the confined tests should be used in Eq. (10-12). 10.4.1.1 The primary testing laboratory shall determine the mean bond stress τref,fc from the results of the combined round-robin tests in accordance with Eq. (10-4). If the mean bond stress corresponding to the tests conducted in any one laboratory exceeds the mean of the combined results from the remaining three laboratories by more than 15 percent, discard that test series and use the remaining three test series to establish τref,fc. Perform this evaluation separately for the results for unconfined and confined tests. F test, f τ ref, fc = ---------------c πd a h ef where τref,fc

MPa

(10-4)

normalized mean bond stress corresponding to round-robin tests, MPa; and Ftest,fc = mean peak load for all round-robin tests normalized to concrete strength fc = 21 MPa in accordance with Section 10.2, N. 10.4.1.2 Based on the results of all round-robin testing, evaluate the adjustment factor αconc in accordance with Eq. (10-5) separately for unconfined and confined roundrobin tests. The minimum value of αconc shall be used in Eq. (10-12). Where the primary laboratory uses data from more than one laboratory for the assessment of servicecondition tension capacity in low-strength concrete, a unique

value of αconc shall be calculated for each laboratory and applied to the service-condition tension tests originating from that laboratory.

where τu,fc

τ ref, fc τ ref, f ------------- > 1.05  α conc = -------------c τ u, fc τ u, fc

(10-5a)

τ ref, fc τ ref, f ------------- < 0.95  α conc = -------------c τ u, fc τ u, fc

(10-5b)

τ ref, f 0.95 ≤ -------------c ≤ 1.05  α conc = 1 τ u, f c

(10-5c)

=

mean bond stress from unconfirmed roundrobin service-condition tests in uncracked concrete normalized to concrete strength fc = 21 MPa in accordance with Section 10.2, MPa; or the mean bond stress from confirmed roundrobin reference tests in uncracked concrete normalized to concrete strength fc = 21 MPa in accordance with Section 10.2, MPa; and τref,fc = as per Eq. (10-4). 10.4.2 Requirements on coefficient of variation R10.4.2 The limits of 20 and 15 percent on the coefficient of variation (COV) for reliability and reference/servicecondition tests, respectively, are derived from extensive experience with adhesive anchor testing. For systems that exhibit larger variation, a reduction is taken on the bond stress in the form of α COV. 10.4.2.1 In each reliability test series, the (COV)νtest,x of the peak loads shall not exceed 30 percent. For all other test series, the (COV)νtest,x of the peak loads shall not exceed 20 percent. 10.4.2.2 For cases where the (COV)νtest,x of the peak loads in reliability tests exceeds 20 percent, determine a reduction factor αCOV in accordance with Eq. (10-6). 10.4.2.3 For cases where the (COV)νtest,x of the peak loads in tests other than reliability tests exceeds 15 percent, determine a reduction factor αCOV in accordance with Eq. (10-6). 10.4.2.4 The minimum value of αCOV as determined in accordance with Sections 10.4.2.2 and 10.4.2.3 shall control for the determination of τk(cr,uncr) in accordance with Eq. (10-12).

=

1 α COV = --------------------------------------------------------- ≤ 1.0 1 + 0.03 ( ν test, x – COV )

(10-6)

where νtest,x is the sample coefficient of variation for test series x equal to the mean divided by the sample standard deviation, percent, and COV is the threshold COV for adhesive anchors, percent (20 for peak loads from reliability tests and 15 for peak loads from tests other than reliability tests). 10.4.3 Comparison with reference tests R10.4.3 The assessment for performance in reliability tests is conducted through the determination of α-values that


41

Table 10.2—Minimum limiting characteristic bond stress τk,min, in MPa Table 3.1 Reduction factors included in the evaluation of τk(cr,uncr) in accordance with Eq. (10-12)

Table 3.2, Table 3.3

Uncracked concrete

Uncracked concrete

Cracked concrete

β

αlt

αst

αdur

αρ

αconc

αCOV

αcat3

4.5

4.5

1.4

β

—

—

—

αρ

αconc

αCOV

αcat3

7

7

2.1

Table 10.3—Reliability tests relevant for determination of min(α/αreq) and minαadh in Eq. (10-12) Table 3.1

Table 3.2

Test no.

Test no.

3

5*

4

3

4

5

Table 3.3 Test no. 6

8*

7

3

4

6*

5

*

Optional tests.

Table 10.4—Service-condition tests relevant for determination of min(α/αreq) and minαadh in Eq. (10-12)

7a

7b

Table 3.1

Table 3.2

Test no.

Test no.

8a

8b*

8c

11a

11b

11c

11d

12a

Table 3.3 Test no. *

12b

12c

17

8a

8b

9a

9b*

9c

*Optional tests.

are, in turn, compared with limiting values α req , below which a reduction in the bond stress is required. 10.4.3.1 For those reliability tests listed in Tables 3.1, 3.2, or 3.3 for which αreq is defined, calculate the value of α using Eq. (10-7) and the results of reference tension tests conducted in the same test member or concrete batch with anchors having the same diameter. τ u, i τ k, i α = min ------- ; -----------τ o, i τ k, o, i where τu,i

=

(10-7)

mean bond stress from reliability test series in concrete batch or test member i, MPa; τo,i = mean bond stress from reference test series in concrete batch or test member i, MPa; = characteristic bond stress from reliability τk,i test series in concrete batch or test member i calculated in accordance with Section 10.3, MPa; and = characteristic bond stress from reference test τk,o,i series in concrete batch or test member i calculated in accordance with Section 10.3, MPa. 10.4.3.2 Omit comparison of the 5 percent fractile values if either of the following conditions is met: • For both test series, the COV of the failure loads v ≤ 10 percent; or • The difference in the number of tests in the series to be compared is Δn ≤ 5 and the COV of the reliability test series is equal to or less than the COV of the reference test series. 10.4.4 Requirements for load-displacement behavior R10.4.4 The point at which the adhesive anchor loses initial adhesion to the concrete and begins to slip, with further resistance provided by the rough interface between

the concrete and the adhesive matrix, is generally determined by examination of the load-slip curve. Where this is not possible, rules are provided for consistent determination of Nadh. Where the measured load at loss of adhesion is less than 50 percent of the mean tensile strength, which is generally an undesirable response, a reduction in the bond stress is taken through the factor α adh. 10.4.4.1 Uncontrolled slip under tension load corresponds to the loss of adhesion between the adhesive material and the concrete. Upon loss of adhesion, both the anchor element and adhesive material are extracted together from the concrete. In such cases, the subsequent load-slip behavior is substantially dependent on the roughness of the drilled hole. The onset of uncontrolled slip is therefore defined as loss of adhesion and the load corresponding to loss of adhesion is denoted as Nadh. 10.4.4.2 Evaluate the load Nadh for each test of the reliability test series (Table 10.3), the service-condition test series (Table 10.4), and the reliability tests (Table 10.5 or 10.6). 10.4.4.3 Evaluate the load Nadh by examination of the load-displacement curve recorded during the test conduct. In general, loss of adhesion is characterized by a significant change in stiffness as reflected in an abrupt change in the slope of load-displacement curve (Fig. 10.1(a)). 10.4.4.4 In cases where the load corresponding to loss of adhesion may not readily be identified by direct observation of the load-displacement curve, evaluate the load Nadh as follows. 1. Compute the tangent to the load-displacement curve at a load N = 0.3Nu, where Nu is the peak tension load resisted by the anchor in the test. In general, the tangent stiffness ktan can be conservatively estimated as the secant stiffness between the origin of the load-displacement curve and the point defined by 0.3Nu and Δ0.3 in Eq. (10-8).

42


(a) Nadh at loss of adhesion.

(c) Nadh when peak load is before Δ lim.

(b) Nadh when peak load-displacement is after Δ lim.

(d) Nadh when Δ 0.3 < 0.05 mm

Fig. 10.1—Evaluation of Nadh load under different load-displacement conditions. Table 10.6—Anchor categories for adhesive anchors subject to installation conditions according to Table 10.8*

Table 10.5—Anchor categories for adhesive anchors subject to installation conditions according to Table 10.7* Threshold value of αreq for selected reliability tests

Threshold value of αreq for selected reliability tests

Reliability test numbers according to Table 3.1, Table 3.2, or Table 3.3

Reliability test numbers according to Table 3.1, Table 3.2, or Table 3.3

Anchor category

Anchor category

2a

2b

2c†

2d†

2e

1

0.95

0.90

0.90

0.90

0.95

1

0.80

0.75

0.75

0.75

0.80

0.90

0.90

0.90

2

0.80

0.75

0.75

0.75

0.80

2

0.70

0.65

0.65

0.65

0.70

0.75

0.75

0.75

3

0.70

0.65

0.65

0.65

0.70

3

0.60

0.55

0.55

0.55

0.60

0.65

0.65

0.65

*(periodic

special inspection) †Optional tests; refer to Table 10.7 for permissible combinations.

*

2a

2b

2c†

2d†

2e

2f‡§

2g†§

2h†§

(continuous special inspection and on-site proof loading program) †Optional tests; refer to Table 10.8 for permissible combinations. ‡ If Test 2g is performed, then Test 2f may be omitted. § Omission of less severe tests is permitted in specific cases: for example, if the desired category is fulfilled with the results of Tests 2b, 2c, and 2d, then Tests 2f, 2g, and 2h may be omitted.


0.3N u – N origin k tan ≈ ----------------------------------Δ 0.3 – Δ origin

(10-8)

where Δ0.3 is the anchor displacement at N = 0.3Nu. 2. Multiply the tangent stiffness by 2/3. 3. Project a straight line from the origin of the loaddisplacement curve with a slope corresponding to the stiffness as calculated in No. 2. 4. The load Nadh shall be taken from the point of intersection between the projected line and the measured loaddisplacement curve (Fig. 10.1(b)). 5. If the peak load occurs at a displacement that is less than that corresponding to the intersection of the projected line and the load-displacement curve, then Nadh shall be taken as the peak load (Fig. 10.1(c)). 6. If the displacement Δ0.3 ≤ 0.05 mm, the origin of the projected line shall be shifted to a point on the loaddisplacement curve given by 0.3Nu and Δ0.3 (Fig. 10.1(d)). 10.4.4.5 For all values of Nadh calculated in accordance with Section 10.4.4.3 or 10.4.4.4, evaluate the adjustment factor αadh using Eq. (10-9). α adh where Nadh,i,j

N adh, i, j = ------------------- ≤ 1.0 0.5N u, i, j

(10-9)

=

tension load corresponding to loss of adhesion for Test Series i, Test j, N; and = peak tension load corresponding to Test Nu,i,j Series i, Test j, N. 10.4.4.6 In cases where a minimum of 10 replicates have been performed in a given test series, it shall be permitted to calculate αadh for that test series in accordance with Eq. (10-10) instead of Eq. (10-9). minN adh, i - ≤ 1.0 α adh = ----------------------0.5N u, i where minNadh,i =

(10-10)

minimum value of adhesion force determined for Test Series i, N; and = mean tension capacity for reliability Test Nu,i Series i, N. 10.4.4.7 Where failure under tension load is characterized by slip between the anchor rod and adhesive material along the entire embedded length—as indicated by extraction of the threaded rod without adherence of adhesive to the rod— evaluation of the load corresponding to loss of adhesion is not required and the value of αadh shall be taken as 1.0. 10.4.5 Bond stress R10.4.5 The calculation of bond stress, made on the basis of the uniform bond stress mode, is assumed essentially independent of concrete strength within the concrete strength range addressed by ACI 318M, Appendix D. An adjustment is made for values determined through confined testing, which generally increases the measured peak load

43

over that measured in unconfined testing because confined testing restrains splitting cracks and provides for a triaxial stress state under the bearing plate. For anchor systems evaluated using the reduced test program of Table 3.3, the bond strength in cracked concrete is given as 25 percent of the value determined in uncracked concrete. The determination of the limiting characteristic bond stress to be used in the design equations of ACI 318M, Appendix D is based on a range of factors that may or may not apply in each case. It is therefore permissible to determine a range of limiting characteristic bond stress values associated with specific conditions. 10.4.5.1 Calculate the corresponding bond stress τi for each service-condition tension test (Table 3.1, Tests 7a and 7b; Table 3.2, Tests 11a through 11d; and Table 3.3, Tests 8a and 8b) in concrete test member i or concrete batch i, normalized to concrete strength equal to 17 MPa using Eq. (10-11). N u, i, f τ i = α setup ---------------c πd a h ef where Nu,i,fc

=

(10-11)

peak tension load measured in a tension test conducted in test series i or concrete batch i, normalized to concrete strength fc = 17 MPa, N; and = 1.0 if service-condition tests are performed as αsetup unconfined tests, 0.75 if service-condition tests are performed as confined tests, and 0.70 if service-condition tests in cracked concrete are performed as confined tests. 10.4.5.2 Nominal characteristic bond stress 10.4.5.2.1 Calculate the nominal characteristic bond stress value τk,nom(cr,uncr) from the values τi in accordance with Eq. (10-3). 10.4.5.2.2 If the bond stress can be shown to vary with anchor diameter in a nonrandom manner, report the bond stress as a continuous function of anchor diameter. Otherwise, calculate a single bond stress τk,nom(cr,uncr) with the results for all diameters using the lowest bond stress. R10.4.5.2.2 While uniform bond stresses calculated in accordance with Eq. (10-11) typically trend downward with increasing anchor diameter, the relationship between bond stress and diameter may be system-dependent and may not show a uniform trend. In this case, where the bond stress rises and falls across several diameters in a random manner, the minimum derived bond stress should be taken across all diameters. Where a trend can be established between bond stress and diameter, a best-fit approximation to the recorded values should be established and used to establish unique bond stresses for each diameter as appropriate. 10.4.5.2.3 For adhesive anchor assessed in accordance with Table 3.3, the value of τk,nom,cr shall be taken as τk,nom,cr = 0.25τk,nom,uncr . 10.4.5.3 Determination of limiting characteristic bond stress 10.4.5.3.1 For adhesive anchors qualified in accordance with Table 3.1, reduce the nominal characteristic bond stress

44


in uncracked concrete, τk,nom,uncr , in accordance with Eq. (1012) and report the limiting characteristic bond stress in uncracked concrete, τk,uncr , for each combination of mandatory and optional use conditions specified. 10.4.5.3.2 For adhesive anchors qualified in accordance with Table 3.2 or 3.3, reduce the nominal characteristic tension bond stresses in cracked and uncracked concrete τk,nom(cr,uncr) in accordance with Eq. (10-12) and report the limiting characteristic bond stresses in cracked concrete, τk,cr , and uncracked concrete, τk,uncr , for each combination of mandatory and optional use conditions specified. τk(cr,uncr) = τk,nom(cr,uncr)βαltαstαdurαραconcαCOVαcat3 MPa (10-12) where β = min[min(α/αreq); minαadh] for the reliability and service-condition tests listed in Tables 10.3 and 10.4; α is the ratio of reliability test result to reference test result evaluated for all reliability tests listed in Table 10.3 (refer to Eq. (10-7)); αadh is the reduction factor for loss of adhesion as evaluated for all reliability tests listed in Table 10.3 and for all service-condition tests listed in Table 10.4 (10.4.4.2); αreq = threshold value of α given in Table 3.1, 3.2, or 3.3; αlt = reduction factor for maximum long-term temperature (refer to Eq. (10-26)); αst = reduction factor for maximum short-term temperature (refer to Eq. (10-27)); αdur = reduction factor for durability (refer to Eq. (10-29)); αρ = minimum reduction factor for reduced load in crack width cycling and freezing-and-thawing tests (refer to Eq. (10-16)); αconc = adjustment factor for regional concrete variation (refer to Section 10.4.1); αCOV = reduction factor associated with the coefficient of variation of peak loads (refer to Eq. (10-6)); and αcat 3 = reduction factor for Anchor Category 3 (refer to Eq. (10-15)). 10.4.5.3.3 If the value τk,cr is derived from servicecondition tests in cracked concrete performed as confined tests, the value τk,cr shall not exceed αconc · τk,nom,cr , where τk,nom,cr is evaluated from service-condition tests in cracked concrete performed as unconfined tests and evaluated in accordance with 10.4.5.2. 10.4.5.4 Further modify the limiting characteristic bond resistance τk(cr,uncr) for sustained tension load cases in accordance with Eq. (10-13). τk,sust(cr,uncr) = τk(cr,uncr)αρ,sust where αρ,sust

MPa

(10-13)

= reduction factor for sustained tension loading in accordance with Eq. (10-17); and τk,sust(cr,uncr) = the sustained tension loading bond resistance, MPa.

10.4.5.5 Further modify the limiting characteristic bond resistance τk(cr,uncr) for seismic tension load cases in accordance with Eq. (10-14). τk,seis(cr,uncr) = τk(cr,uncr)αN,seis MPa where αN,seis

(10-14)

= reduction factor for seismic tension loading (Eq. (10-30)); and τk,seis(cr,uncr)= seismic tension bond resistances in cracked and uncracked concrete, respectively, MPa. 10.4.5.6 Minimum limiting characteristic bond stress 10.4.5.6.1 The nominal characteristic bond stress evaluated in accordance with Eq. (10-12) shall not be less than that shown in Table 10.2. Where this condition is not satisfied, the product shall be reported as unqualified. R10.4.5.6.1 ACI 318M, Appendix D, contains default minimum bond stresses that may be used for design in the absence of direct information regarding the bond stresses associated with common use conditions for a qualified product. Because any qualified product is assumed to be able to develop these minimum bond stresses, the same values (as derived from Eq. (10-12) for the specific constellation of use parameters described in ACI 318M, Appendix D) must be taken as minimums for the qualification. A basic differentiation is made between outdoor and indoor use. Outdoor implies exposure to weather such as water, temperature, and aggressive environments, while indoor is associated with a less demanding set of parameters. This is reflected in the omission of the α lt , α st , and α dur from the second higher set of bond stresses corresponding to indoor uses in ACI 318M, Appendix D (Table 10.2). 10.4.6 Anchor category R10.4.6 The anchor category is determined by the results of reliability tests in terms of the same α-factors used to determine the limiting characteristic bond stress. Two sets of α req values are provided for determining the anchor category, each associated with specific job-site inspection and testing requirements. For anchors that are assessed under the more relaxed threshold values for the determination of the anchor category, more stringent requirements for job-site inspection and testing are required. For anchors that do not meet the threshold values for the lowest anchor category, a further reduction in the limiting characteristic bond stress is taken. 10.4.6.1 Assign an anchor category to the tested anchor system in accordance with Table 10.5 or 10.6, depending on the installation conditions specified for the anchor and the results of the reliability tests. The minimum value of α and αadh shall control for the determination of the anchor category. 10.4.6.2 Where the controlling value of α or αadh is less than the value of αreq corresponding to Anchor Category 3 in Table 10.5 or 10.6, the anchor shall be assigned to Anchor Category 3 and an additional reduction factor αcat3 for the determination of τk(cr,uncr) in accordance with Eq. (10-12) shall be determined in accordance with Eq. (10-15). For all other cases, αcat3 shall be taken as 1.0.


α adh α α cat3 = min min -------------------- ; min ------------------- ≤ 1.0 (10-15) α req, cat3 α req, cat3 where αreq,cat3 = αreq corresponding to Anchor Category 3 for corresponding reliability test in accordance with Table 10.5 or 10.6. 10.4.6.3 The anchor category shall be reported in Table 11.1 or 11.2. 10.4.7 Adjustment for reduced load in crack width cycling, freezing-and-thawing, and sustained load tests is permissible if the limiting characteristic bond stress is reduced (10.9, 10.10, and 10.11). R10.4.7 Sustained loads are required for the crack width cycling test, the freezing-and-thawing test, the standard temperature creep tests, and the maximum long-term temperature creep tests. If the sustained load used in the test is less than required, a reduction on the limiting characteristic bond stress is taken. 10.4.7.1 Where a reduced sustained load is required to meet the displacement requirements in the crack width cycling or freezing-and-thawing tests, the reduction factor αρ shall be evaluated in accordance with Eq. (10-16). N red α ρ = min ---------- ≤ 1.0 N req

(10-16)

where Nred = reduced sustained load in a reliability test series as required to satisfy displacement criteria, N; and Nreq = required sustained load for a reliability test series—Nw for tests in accordance with Eq. (7-1), and Nsust,ft for tests in accordance with Eq. (7-2), N. 10.4.7.2 Where a reduced sustained load is required to meet the displacement requirements in the sustained load test, the reduction factor αρ,sust shall be evaluated in accordance with Eq. (10-17). N red - ≤ 1.0 α ρ, sust = min --------------N sust, lt

(10-17)

where Nred = reduced sustained load applied in the sustained load test as required to satisfy displacement criteria, N; and Nsust,lt = sustained load in accordance with Eq. (7-3), N. 10.4.8 Determination of effectiveness factors 10.4.8.1 It shall be permitted to evaluate the effectiveness factors kcr and kuncr for adhesive anchors in accordance with ACI 355.2. Unconfined tension tests shall be conducted at the smallest, middle, and largest diameters in low- and highstrength concrete with five replicates per test series. The tests shall be conducted at the greatest embedment depth for which concrete cone failure is anticipated to occur and may be approximated using Eq. (10-18). The assessment of the effectiveness factor shall fulfill the requirements of ACI 355.2 for all test series.

h ef where τu,fc,uncr = km,uncr

=

τ u, fc, uncr πd a 2 ----------------------------k m, uncr = ---------------------------------f c′

mm

45

(10-18)

mean bond strength evaluated from unconfined tests in uncracked concrete normalized to fc′ , MPa; and 17 for recognition of kuncr = 13, and 15 for recognition of kuncr = 11.

10.5—Assessment of steel tension capacity R10.5 Where the strength of the anchor element is addressed by other standards, for example, all-thread rods by ASTM, separate tension tests to determine the tension strength of the rod/nut assembly are not required. 10.5.1 Evaluate the steel tension capacity in accordance with D.5.1.2 of ACI 318M. 10.5.2 Where the steel anchor element carrying tension load has a variable cross section, Ase,N shall be taken as the minimum cross-sectional area over the load-bearing length of the anchor. 10.6—Assessment of steel shear capacity (8.11) 10.6.1 For anchors without a reduced cross section within five diameters of the shear plane, the steel shear capacity shall be evaluated in accordance with D.6.1.2 of ACI 318M. R10.6.1 In no case shall the shear strength of an anchor element exceed the value given in ACI 318M, Appendix D. 10.6.1.1 For anchors without threads in the critical shear plane, Ase,V shall be taken as the gross anchor cross-sectional area. 10.6.1.2 For anchors with threads in the shear plane but without a reduced cross section, Ase,V shall be taken in accordance with Eq. (10-19). π 0.9743 2 A se, V = ---  d a – ---------------- mm2 nt  4

(10-19)

where nt is the number of threads per millimeter. 10.6.1.3 For anchors that exhibit pullout failure in unconfined tension tests at hef = hef,min , determine the characteristic shear capacity Vs by test as prescribed in 8.11, but Vs shall not exceed the value determined in accordance with D.6.1.2 of ACI 318M, where Ase is as defined in 10.6.1.1 or 10.6.1.2. 10.6.2 For anchors with a reduced cross section within five diameters of the shear plane, the characteristic shear capacity Vs shall be determined by test as prescribed in 8.11, but shall not exceed the value determined in accordance with D.6.1.2 of ACI 318M, assuming an unreduced cross section. 10.6.3 Further modify the characteristic shear capacity Vs for seismic load cases in accordance with Eq. (10-20) Vs,seis = VsαV,seis N

(10-20)

46

where αV,seis


reduction factor for seismic shear loading, refer to Eq. (10-31); = characteristic steel shear capacity determined Vs in accordance with 10.6.1 or 10.6.2; and = seismic shear capacity of the anchor as Vs,seis governed by steel failure. 10.6.4 For anchor diameters not tested in shear, the minimum values of αV,seis determined for the tested anchor diameters closest to the untested diameters shall be used in Eq. (10-20). 10.6.5 Report shear capacities obtained in Table 11.1 or 11.2. 10.7—Assessment of minimum member thickness (9.2) R10.7 When anchors are to be installed with small backside cover distance, which is the distance from the end of the drilled hole to the remote concrete face, the impact energy of the drilling system is decisive for preventing spalling of the concrete at the remote face. 10.7.1 In those test series where the minimum member thickness hmin is required to be used, conduct tests in members having the minimum member thicknesses specified for each anchor type, diameter, and embedment. The minimum member thickness hmin shall not be less than the value given by Eq. (10-21). hmin = hef + Δh ≥ 50 mm

(10-21)

where Δh ≥ 2do ≥ 30 mm applies to all anchor types without restriction and Δh ≥ 2do ≥ 15 mm applies to all anchor types in cases where the remote face of the concrete member can be inspected. If concrete breakthrough occurs during drilling, take measures to ensure that the effective anchor embedment has not been compromised and that adhesive material losses are prevented (Δh = 0 applies to injection anchor systems in cases where the effective anchor embedment is adjusted for spalling on the backside of the concrete member and measures are taken to ensure that adhesive material losses are prevented). 10.8—Assessment of maximum tightening torque (7.19) R10.8 Because the relationship between torque and tension in a bolted connection is highly dependent on the condition of the threads, fraying surfaces, and the presence of lubricants or contaminants, the specific conditions associated with the reported torque value should be stated. 10.8.1 The torque test shall achieve a torque resistance of at least 1.3Tinst. The anchor shall not turn in the anchor hole prior to reaching a torque resistance of 1.3Tinst. In addition, Eq. (10-22) shall be fulfilled. If this requirement is not met, reduce the installation torque Tinst as required to fulfill the requirement. N95% ≤ min[Fy ; 0.8Nk,test] where

95 percent fractile (90 percent confidence) of the induced tension force corresponding to 1.3Tinst; = characteristic tension capacity evaluated Nk,test from reference tension tests in low-strength concrete (Table 3.1, Test 1a; Table 3.2, Test 1a; and Table 3.3, Test 1a), N; and = Ase,N fya for bolts with a defined yield stress Fy and Fy = Ase,N ⋅ 0.8futa for bolts without a well-defined yield stress, MPa. 10.8.2 It shall be permitted to satisfy the requirement of Eq. (10-22) using a calculated value for N95% in accordance with Eq. (10-23). N95%

=

(10-22)

=

1.3T inst N 95% = ----------------kf da

(10-23)

where kf is the friction factor of threads. The friction factor shall be taken as a lower-bound value. For normal threaded rods without lubricants or friction-reducing coatings, k = 0.2 may be assumed. 10.9—Assessment of behavior under crack cycling (7.15) R10.9 Compare Fig. 7.1 to Fig. 8.1 in ACI 355.2. Unlike expansion and undercut anchors, adhesive anchors do not develop wedging forces in the crack during the conduct of the crack movement test. As such, changes in the lower crack width with increasing crack cycling are likely to be due to other causes, for example, changes in the bond relationship of the embedded reinforcement in the test specimen. 10.9.1 In each test in cracks whose opening width is cycled, the cumulative recorded anchor displacement shall not exceed 2 mm following the initial 20 cycles of crack opening and closing, nor 3 mm following 1000 cycles. 10.9.2 If the anchor displacement exceeds these limits during the crack-cycling portion of the test, it shall be permitted to increase the number of replicates. For a sample size of 10 to 20 replicates, one of the tested anchors shall be permitted to exhibit a maximum displacement of 3 mm after the initial 20 cycles and 4 mm after 1000 cycles. For sample sizes larger than 20, 5 percent of the tested anchors shall be permitted to exhibit these increased displacements. If the requirements are not met, repeat the tests with a reduced sustained load until the requirements are met and evaluate the reduction factor αρ in accordance with 10.4.7. For anchors evaluated in accordance with Table 3.3, reduction of the sustained load is not permitted and anchors that fail to satisfy the displacement requirements of this section are not qualified for use in cracked concrete in accordance with this standard. 10.9.3 The value of αreq for the residual tension capacity is 0.90. 10.9.3.1 For assessment under Table 3.3, the reference value for cracked concrete used to determine α shall be 0.25 times the reference value in uncracked concrete, normalized to 17 MPa.


10.10—Assessment of freezing-and-thawing behavior (7.16) 10.10.1 The change in displacement as a function of time in the freezing-and-thawing tests (7.16) shall continually decrease with an increasing number of freezing-and-thawing cycles and shall approach zero. 10.10.2 If the requirement on displacement is not met, reduce the sustained load until the requirement is met and evaluate the reduction factor αρ in accordance with 10.4.7. 10.10.3 The value of αreq for the residual tension capacity shall be 0.90. 10.11—Assessment of sustained load behavior (7.17) R10.11 Equation (10-24) provides a conservative estimate of anchor displacement over long periods of sustained loading. The determination of the coefficients a and b is sensitive to the number of data points evaluated and should be approached with care. 10.11.1 The total displacement over the anchor intended service life, which includes the initial elastic displacement plus the creep displacement, is determined for each specimen by projecting a logarithmic trend line forward over the intended anchor service life. The trend line shall be determined by calculating a least-squares fit through the data points using Eq. (10-24) and shall be constructed with data from the last 20 days, with a minimum of 20 data points, of the creep test. Δ(t) = Δt=0 + at b where Δ(t)

(10-24)

=

total displacement recorded in the test at time t, mm; Δt=0 = initial displacement under sustained load, mm; t = time corresponding to the total recorded displacement, in hours; and a,b = constants evaluated by regression analysis. 10.11.2 Calculate the estimated displacement corresponding to the anchor intended service life for each test using Eq. (10-25). Δservice = Δt=0 + a(tservice)b where Δservice

=

(10-25)

extrapolated estimate of the total displacement over the anchor intended service life, mm; = initial displacement recorded under sustained Δt=0 load, mm; tservice = intended anchor service life, in hours, at 50 years (standard temperature conditions) and 10 years (elevated temperature conditions); and a,b = constants evaluated by regression analysis in accordance with 10.11.1. 10.11.3 The mean values of the extrapolated estimates of the total displacement over the anchor intended service life Δservice at standard temperature and at the long-term elevated temperature shall not exceed Δlim, where Δlim is the mean displacement corresponding to loss of adhesion Nadh for adhesive anchors (10.4.4, Fig. 10.1(a) through (d)) as

47

measured in the corresponding reference tests at standard temperature or maximum long-term elevated temperature, respectively. It shall be permitted to omit the sustained load tests at standard temperature, however, if the displacements measured in the sustained load tests at long-term temperature are extrapolated to 50 years and the mean value Δservice does not exceed Δlim as defined in 10.11.3. 10.11.4 The calculated estimated displacement Δservice for any one test shall not exceed 1.2Δlim with Δlim as defined in 10.11.3. 10.11.5 If the requirement on displacement is not met, reduce the sustained load until the requirement is met and evaluate the reduction factor αρ,sust in accordance with 10.4.7. The applied sustained load shall not be less than 40 percent of Nsust,lt as determined in accordance with Eq. (7-3). 10.11.6 The value of αreq for the residual tension capacity shall be 0.90. 10.12—Assessment of performance associated with installation direction (7.18) R10.12 While many injectable adhesives are formulated as gels with a viscosity that is suitable to permit their use in other than down-hole applications, the injection of adhesive and positioning of the anchor element for orientations where gravity works against the installation may require special techniques and equipment. Temperature extremes can also affect the installation process, whereby hotter ambient temperatures will simultaneously decrease the adhesive viscosity and accelerate the curing process and colder temperatures will generally increase viscosity and retard curing. The use of a clear polycarbonate tube to simulate blind injection conditions, as shown in Fig. 10.2, can be particularly effective for establishing the effectiveness of installation procedures, especially for deeper holes. 10.12.1 When installed horizontally and overhead in accordance with the MPII, the annular gap around the anchor element shall remain completely filled with adhesive and the anchor element shall not displace downward more than da/20 or 2.5 mm during the cure time. Include the following criteria in the assessment: 1. The adequacy of the MPII for the installation orientation being evaluated. 2. For overhead installations, the adequacy of measures, as required, to prevent sag of the anchor element prior to adhesive cure (Fig. 10.2(a)). 3. For overhead and horizontal installations, the adequacy of measures, as required, to capture excess adhesive during installation of the anchor element, to protect the unbonded portion of the anchor element from adhesive, and to ensure that the annular gap around the anchor element is completely filled with adhesive over the bonded length (Fig. 10.2(b) and (c)). 4. The adequacy of installation procedures to prevent formation of gaps and/or trapped air in the adhesive along bonded length of the anchor (Fig. 10.2(d)). 10.12.2 The value of αreq for the tension capacity shall be 0.90.

48


Fig. 10.2—Assessment criteria for evaluation of effectiveness of installation procedures for overhead installations. 10.12.3 Where testing and assessment to address sensitivity to installation direction in accordance with this standard is not conducted, the product shall be limited to down-hole installation only and the product labeling will include the notification shown in Fig. 7.2. 10.13—Assessment of performance at elevated temperature (8.5) R10.13 The assessment for performance at the long- and short-term elevated temperature permits a 20 percent decrease in strength for the short-term event. Short-term elevated temperatures are those associated with diurnal cycles or other transient phenomena. Long-term elevated temperatures are those that occur over extended periods of time. 10.13.1 Calculate αlt from the tension test results at the long-term test temperature using Eq. (10-26). N N k, lt α lt = min ------lt ; ---------≤ 1.0 N o N k, o

(10-26)

10.13.2 Calculate αst from the tension test results at the short-term test temperature using Eq. (10-27). α st

N k, st N st = min ------------- ; ----------------- ≤ 1.0 0.8N lt 0.8N k, lt

10.14—Assessment of performance with decreased installation temperature (8.6) R10.14 A distinction is made for systems that are intended for installation at 10°C or above and those intended for installation at temperatures below 10°C. At low temperatures, curing of the adhesive may be retarded to the degree that the bond is developed in part through freezing of the adhesive. This bond mechanism may not be reliable if the concrete temperature should rise. 10.14.1 For anchors recommended for installation in concrete temperatures below 10°C, the mean and the 5 percent fractile of the failure loads associated with the reduced temperature installation shall equal or exceed the mean and the 5 percent fractile of the corresponding reference tests. Alternatively, it shall be shown that the two data sets are statistically equivalent. 10.14.1.1 Omit comparison of the 5 percent fractile values if either of the following conditions are met: • For both test series, the COV of the failure loads is v ≤ 10%. • The difference in the number of tests in each series Δn ≤ 5 and the COV of the temperature test series is equal to or less than the COV of the reference test series. 10.14.2 For anchors recommended for installation in concrete temperatures below 5°C, the conditions of 10.14.1 shall be fulfilled. In addition, the displacement of the anchor under sustained load just prior to tension testing to failure shall stabilize to the degree that an assessment can be made that failure is unlikely to occur. 10.14.3 Retest anchors that do not fulfill the requirements for a given target temperature at a temperature at which the requirements are fulfilled. Report the temperature at which the requirements are fulfilled as the minimum concrete temperature at the time of installation. 10.15—Assessment for cure time at standard temperature (8.7) R10.15 Manufacturers usually provide cure times for a variety of temperatures, typically in the MPII. Tests for the cure time at standard temperature represent a spot check of the validity of the data provided by the manufacturer. 10.15.1 Assess the results of the tests for curing at standard temperature in accordance with Eq. (10-28). N k, cure N cure min --------------------- ; ------------------------- ≥ 0.9 N N cure+24h k, cure+24h

(10-28)

(10-27)

10.13.3 Omit comparison of the 5 percent fractile values if either of the following conditions is met: • For both test series, the COV of the failure loads v ≤ 10%. • The difference in the number of tests in each series Δn ≤ 5 and the COV of the temperature test series is equal to or less than the COV of the reference test series. 10.13.4 Refer to Section 10.4.4 for requirements on displacement.

where Ncure

=

Ncure+24h =

Nk,cure

=

mean tension capacity corresponding to the manufacturer’s published minimum cure time, N; mean tension capacity corresponding to the manufacturer’s published minimum cure time plus 24 hours, N; characteristic tension capacity corresponding to the manufacturer’s published minimum cure time, N; and


Nk,cure+24h =

characteristic tension capacity corresponding to the manufacturer’s published minimum cure time plus 24 hours, N. 10.15.2 Omit comparison of the 5 percent fractile values if either of the following conditions is met. • For both test series, the COV of the failure loads is v ≥ 10 percent; or • The difference in the number of tests in each series is Δn ≤ 5 and the COV of the temperature test series is equal to or less than the COV of the reference test series. 10.15.3 If the conditions of Eq. (10-28) are not fulfilled, increase the cure time and repeat the test until Eq. (10-28) is fulfilled. 10.16—Assessment of durability requirement (8.8) R10.16 Durability is assessed on the basis of the mean of the punch tests. 10.16.1 Requirement—Calculate the reduction factor αdur , lower of αalk , and αsulf , when punch tests are performed, using Eq. (10-29). minτ dur, i α dur = ---------------------- ≤ 1.0 0.95τ o, i where τdur,i

=

τo,i

=

(10-29)

mean bond stress corresponding to durability tests with test member i or concrete batch i stored in different media calculated according to Eq. (8-1); and mean reference bond stress corresponding to durability tests with test member i or concrete batch i calculated according to Eq. (8-1).

10.17—Assessment of performance in corner test (8.9) 10.17.1 The tension capacity of the anchor positioned in the corner of a test member with edge distances cac and minimum member thickness hmin shall be statistically equivalent to the tension capacity from reference tests performed away from the edges. Report the critical edge distance cac and the corresponding minimum member thickness in Table 11.1 or 11.2. R10.17.1 Several combinations of critical edge distance and member thickness may be reported, depending on the extent of testing performed. 10.18—Assessment of performance in minimum spacing and edge distance test (8.10) R10.18 Several combinations of minimum edge distance, spacing, and member thickness may be reported, depending on the extent of testing performed. 10.18.1 Requirement for torque tests—The 5 percent fractile of the maximum recorded torque calculated according to 10.3 and normalized to fc = 17 MPa according to 10.23 shall be: • Greater than the lesser of 1.7Tinst and 1.0Tinst + 135 N-m for anchors to be designed assuming uncracked concrete conditions.

49

Greater than the lesser of 1.3Tinst and 1.0Tinst + 40 N-m for anchors that are qualified for cracked concrete and are to be designed assuming cracked concrete conditions where the crack width is restrained by reinforcement in the concrete. 10.18.2 If these requirements are not met, determine cmin and smin by either: 1. Holding cmin constant and increase smin until the requirements are fulfilled. 2. Holding smin constant and increase cmin until the requirements are fulfilled. 3. Increasing cmin and smin until the requirements are fulfilled. 10.18.3 Requirements for load tests—The concrete shall not crack during anchor installation. The mean failure load shall equal or exceed 90 percent of the expected load calculated on the basis of the service-condition tests in uncracked concrete, taking into account the effects of reduced spacing and edge distances. 10.18.4 Report the minimum edge and spacing distances and the associated minimum member thickness. •

10.19—Assessment of performance under seismic tension (8.12) R10.19 The assignment of specific anchor bond strength reductions corresponding to seismic loading may be made for specific anchor diameters. 10.19.1 All anchors in a test series shall complete the simulated seismic-tension load history specified in Table 8.2 and Fig. 8.3. Failure of an anchor to develop the required tension resistance in any cycle prior to completing the loading history specified in Table 8.2 and Fig. 8.3 shall be recorded as an unsuccessful test. The mean residual capacity of the anchors in the test series shall be equal to or greater than 160 percent of Neq as given in Eq. (8-2). 10.19.1.1 Successful completion of the cyclic loading history and fulfillment of the residual tension capacity requirement of this section shall be noted in Table 11.2. 10.19.1.2 If the anchor does not fulfill the aforementioned requirements at Neq, it shall be permitted to conduct the test with reduced cyclic loads conforming to the loading history specified in Table 8.2 and Fig. 8.3 whereby Neq,reduced , Ni,reduced , and Nm,reduced are substituted for Neq , Ni , and Nm , respectively. All anchors in a test series shall complete the simulated seismic-tension load history. Failure of an anchor to develop the required tension resistance in any cycle prior to completing the loading history given in Table 8.2 and Fig. 8.3 shall be recorded as an unsuccessful test. The mean residual capacity of the anchors in the test series in the tension test shall be at least 160 percent of the reduced peak load Neq,reduced. Report successful completion of the reduced cyclic loading history and fulfillment of the residual tension capacity requirement of this section together with the reduction factor αNeq as given by Eq. (10-30). N eq, reduced α N, seis = ------------------------N eq

(10-30)

50


Table 10.7—Limitations on installation conditions for adhesive anchors installed under periodic special inspection only*† Table 3.1, Table 3.2, or Table 3.3 optional reliability tests performed Installation conditions permitted

2c

2d

Installation in interior and exterior locations shall be permitted

—

—

Installation in water-filled holes shall be permitted

X

—

Installation in submerged concrete shall be permitted

—

X

*

Refer to Chapter 13 for quality control requirements. to Table 10.9 for limitations of use.

†Refer

Table 10.8—Limitations on installation conditions for adhesive anchors installed under continuous special inspection and an on-site proof loading program*†‡ Installation conditions permitted

Table 3.1, Table 3.2, or Table 3.3 optional reliability tests performed 2c

2d

2g

2h

Installation in interior and exterior locations shall be permitted

—

—

—

—

Installation in water-filled holes shall be permitted

X

—

X

—

Installation in submerged concrete shall be permitted

—

X

—

X

*

Refer to Chapter 13 for quality control requirements. to Table 10.9 for limitations. ‡Omission of less severe tests is permitted in specific cases.

with reduced cyclic loads conforming to the loading history specified in Table 8.3 and Fig. 8.4 whereby Veq,reduced, Vi,reduced, and Vm,reduced are substituted for Veq, Vi, and Vm, respectively. All anchors in a test series shall complete the simulated seismic-shear load history. Failure of an anchor to develop the required shear resistance in any cycle prior to completing the loading history given Table 8.3 and Fig. 8.4 shall be recorded as an unsuccessful test. The mean residual capacity of the anchors in the test series in the tension test shall be at least 160 percent of the reduced peak load Veq,reduced. Report successful completion of the reduced cyclic loading history and fulfillment of the residual shear capacity requirement of this section together with a reduction factor αV,seis as given by Eq. (10-31). V eq, reduced α V, seis = -----------------------V eq

(10-31)

10.20.2 The reduction factor αV,seis shall be used to determine Vs,seis in accordance with 10.6.3. Report this value in Table 11.2 for load combinations that include seismic loads. 10.20.3 For a given anchor diameter, all embedment depths greater than the tested embedment depth shall be qualified at the value of Vs determined in accordance with 10.6. Use linear interpolation for the evaluation of Vs for embedment depths between the tested embedment depths.

†Refer

10.19.1.3 The reduction factor αN,seis shall be used to determine τk,seis(cr,uncr) in accordance with 10.4.5.5. Report these values in Table 11.2 for load combinations that include seismic loading. 10.20—Assessment of performance under seismic shear (8.13) R10.20 The assignment of specific anchor shear strength reductions corresponding to seismic loading may be made for specific anchor diameters. 10.20.1 All anchors in a test series shall complete the simulated seismic-shear load history specified in Table 8.3 and Fig. 8.4. Failure of an anchor to develop the required shear resistance in any cycle prior to completing the specified loading history in Table 8.3 and Fig. 8.4 shall be recorded as an unsuccessful test. The mean residual capacity of the anchors in the test series shall be at least 160 percent of Veq , as given by Eq. (8-5) or (8-8). 10.20.1.1 Report successful completion of the cyclic loading history and fulfillment of the residual shear capacity requirement of this section together with an anchor capacity Vs,seis, equal to the characteristic value Vst, determined from the static shear test results to be reported in Table 11.2 for use in cases that include seismic loading. 10.20.1.2 If the anchor fails to fulfill the aforementioned requirements at Veq, it shall be permitted to conduct the test

10.21—Establishment of hole-cleaning procedures R10.21 Hole-cleaning procedures are critical to the performance of most adhesive anchor systems. It is therefore critical that the hole-cleaning procedures used in the test program correspond to those given in the MPII. The ITEA should receive no supplemental instruction regarding the installation of the adhesive anchor system beyond what is contained in the MPII. It is recognized that each laboratory may have varying levels of experience with respect to anchor installations. Nevertheless, the evaluation of the adhesive anchor system should include a critical evaluation of the effectiveness of the MPII as an instrument for ensuring correct anchor installation and the MPII should be viewed as a component of the adhesive anchor system, subject to quality control requirements and specifically linked to the test data generated as part of the qualification under this standard. 10.21.1 Hole-cleaning procedures given in the MPII shall correspond to the procedures used in the test program. If no hole cleaning is used in the testing program, it shall be permitted to specify installation of the anchor without hole cleaning. 10.21.2 Report hole-cleaning procedures (refer to 7.5.3). 10.22—Establishment of on-site quality control and installation conditions R10.22 Installation quality control is a critical component in ensuring achievement of the predicted design strengths. Two levels of quality control are provided. 10.22.1 For restrictions on installation conditions based on the level of on-site quality control and reliability tests


51

Table 10.9—Limitations on use of adhesive anchors based on environmental conditions Reliability and service-condition tests performed Table 3.1

Table 3.2

Table 3.3

Permitted use conditions

3

9a

9b

6

13a

13b

4

10a

10b

Applications limited to dry interior environments without aggressive atmospheric conditions

—

X

—

—

X

—

—

X

—

Without aggressive atmospheric conditions†

X

X

—

X

X

—

X

X

—

With aggressive atmospheric conditions‡

X

X

X

X

X

X

X

X

X

Applications in interior or exterior environments* *

Use in exterior or aggressive exposure conditions is predicated on the appropriate steel type or coating. Classification predicated on exposure to alkaline environment but no exposure to sulfuric atmosphere. ‡ Classification predicated on exposure to alkaline environment and sulfuric atmosphere. †

performed, refer to Tables 10.7 and 10.8. For the determination of the anchor category, refer to 10.4.6. 10.22.2 Report the required installation conditions.

•

10.23—Assessment based on installation and environmental conditions 10.23.1 For use restrictions based on installation conditions and environmental tests performed within the anchor assessment program, refer to Table 10.9. Report any use restrictions. R10.23.1 The response of the adhesive anchor system to other environmental aggressors may be assessed.

• • •

10.24—Assessment for fire exposure 10.24.1 Assessment of resistance to fire exposure shall be based on a recognized national standard for the testing and assessment of structural components under fire conditions. R10.24.1 Anchor testing under fire exposure conditions typically consists of placing a static weight on the anchor in a burn chamber and measuring the time to failure for a specific time-temperature curve. While standards have been issued for the testing and assessment of anchors for exposure to fire, little guidance exists for the use of the resulting resistance values in design. CHAPTER 11—DATA PRESENTATION 11.1—General requirements Report the following information. 11.1.1 Presentation of the anchor evaluation shall include the reporting requirements of ASTM E488 and sufficient information for product identification, design, installation, and quality control. 11.2—Contents of the evaluation report R11.2 It is important that all of the restrictions on use and special inspection requirements be included in the report, as well as a true facsimile of the MPII used for the evaluation program. 11.2.1 The report shall include, but not be limited to, the following:

•

• • •

Description of adhesive anchor system components including constituent materials and markings. The MPII as used in the testing and evaluation of the adhesive anchor system, reproduced in full. Special inspection requirements. Anchor performance data in accordance with 10.3. Limitations on installation conditions in accordance with Table 10.7 or Table 10.8. Limitations on use based on environmental conditions in accordance with Table 10.9. Service temperature range. Restrictions on use with respect to concrete cracking as follows. ° This version applies where the anchor has been qualified in accordance with Table 3.1. Anchors are limited to installation in concrete that is uncracked and may be expected to remain uncracked for the service life of the anchor. ° This version applies where the anchor has been qualified in accordance with Table 3.2 or Table 3.3. Anchors are permitted to be installed in concrete that is cracked and may be expected to crack during the service life of the anchor.

11.3—Data presentation R11.3 Tables 11.1 and 11.2 are intended to express one option for conveying the results of the assessment in tabular form. Other table configurations are permissible. The adjustments on bond stress for temperature, environmental exposure, and sustained tension loading may be expressed by listing the adjusted bond stress or including a properly designated factor. In the sample tables, the symbol κ is used for this purpose. 11.3.1 Report the data required by ACI 355.4M in the format shown in Table 11.1 or Table 11.2. The format may be modified as appropriate provided that the basic intent of the content of these tables is met. R11.3.1 The format provided is suggested. Other formats are permissible.

52


Table 11.1—Sample format for reporting adhesive anchor data for anchors qualified for use in uncracked concrete only Anchor qualified per Table 3.1—Test program for evaluating adhesive anchor systems for use in uncracked concrete Anchor manufacturer

Anchor name*

Criteria and code(s) Symbol

Criteria section of reference standard†

Units‡

Anchor outside diameter

da

mm

Hole diameter

do

mm

Installation torque

§

Maximum permissible

torque||

Effective cross-sectional area of anchor element

Anchor bolt

Anchor sleeve

Tinst

N-m

Tmax

N-m

Ase

mm2

Minimum specified yield strength

fy

ASTM F606

MPa

Minimum specified ultimate strength

fut

ASTM F606

MPa

Bolt steel elongation at break

—

ASTM F606

%

Bolt steel cross section reduction at break

—

ASTM F606

%


fy,sl

ASTM E8

MPa


fut,sl

ASTM E8

MPa

Nominal steel tension strength of single anchor

Ns

N

Strength reduction factor for tension steel failure modes

φ

—

Nominal steel shear strength of a single anchor

Vs

N

Strength reduction factor for shear steel failure modes

φ

—

Effective embedment depth(s)

hef

mm

inspection#

—

—

—

—

Characteristic limiting bond resistance in uncracked concrete

τk,uncr

MPa

Adjustment for Temperature Category B

κtemp B

—

Adjustment for exposure to sulfur

κsulfur

—

Anchor category for continuous special

Anchor category for periodic special inspection

Adjustment for sustained tension loading

κsust

—

Minimum member thickness

hmin

mm

Minimum anchor spacing

smin

mm

Minimum edge distance

cmin

mm

Critical edge distance

cac

mm

Special reporting requirements *

Trade name. For anchors distributed under multiple trade names, list all. ASTM or ISO standards. units shown. § Manufacturer’s recommended torque as applicable for adhesive anchors. || Limit on torque as governed by bolt stress. # Includes proof load program. †

‡Fractional

Anchor nominal diameters


53

Table 11.2—Sample format for reporting adhesive anchor data for anchors qualified for use in both cracked and uncracked concrete Anchor qualified per Table 3.2 or Table 3.3—Test program for evaluating adhesive anchor systems for use in cracked and uncracked concrete Anchor manufacturer

Anchor name*

Criteria and code(s) Symbol

Criteria section of reference standard†

Units‡

Anchor outside diameter

da

mm

Hole diameter

do

mm

Installation torque

§

Maximum permissible

torque||

Effective bolt tension area

Tinst

N-m

Tmax

N-m

Ase

mm2

fy

ASTM F606

MPa


fut

ASTM F606

MPa

Bolt steel elongation at break

—

ASTM F606

%

Bolt steel cross section reduction at break

—

ASTM F606

%


fy,sl

ASTM E8

MPa


fut,sl

ASTM E8

MPa

Minimum specified yield strength Anchor bolt

Anchor sleeve

Nominal steel tension strength of single anchor

Ns

Strength reduction factor for tension steel failure modes

φ

Nominal steel shear strength of a single anchor

Vs

Strength reduction factor for shear steel failure modes

φ

Effective embedment depth(s)

hef

Anchor category for continuous special inspection#

—

—

Anchor category for periodic special inspection

—

—

Characteristic limiting bond resistance in uncracked concrete τk,uncr

N N mm

MPa

τk,cr

MPa

Adjustment for Temperature Category B

κtemp B

—

Adjustment for exposure to sulfur

κsulfur

—

Adjustment for sustained tension loading

κsust

—

Minimum member thickness

hmin

mm

Minimum anchor spacing

smin

mm

Minimum edge distance

cmin

mm

cac

mm

Characteristic limiting bond resistance in cracked concrete

Critical edge distance

Anchor nominal diameters

Optional simulated seismic tests (Table 3.2 only) Adjustment for seismic tension loading

κseismic

—

Nominal strength of a single anchor for seismic shear loading

Vk,seis

N

Special reporting requirements *

Trade name. For anchors distributed under multiple trade names, list all. ASTM or ISO standards. ‡Fractional units shown. §Manufacturer’s recommended torque as applicable for adhesive anchors. || Limit on torque as governed by bolt stress. # Includes proof load program. †

CHAPTER 12—INDEPENDENT TESTING AND EVALUATION AGENCY REQUIREMENTS 12.1—General requirements The testing and evaluation of anchors under ACI 355.4M shall be performed or witnessed by an independent testing and evaluation agency (ITEA) or agencies accredited under ISO/IEC 17025 by a recognized accreditation body conforming to the requirements of ISO/IEC 17011. In addition to these standards, listing of the ITEA shall be predicated on documented experience in the testing and evaluation of anchors according to ASTM E488, ASTM E1512, and ACI 355.2, including

demonstrated competence to perform the tests described in ACI 355.4M. The ITEA shall verify that all elements of the test program and analysis are in compliance with ACI 355.4M and shall conduct or directly verify all procedures. 12.2—Certification The test reports and evaluation reports shall be certified by a licensed design professional (or equivalent technical competency where licensing provisions do not exist) and is employed or retained by the ITEA.

54


CHAPTER 13—QUALITY CONTROL REQUIREMENTS 13.1—Quality assurance program Anchors shall be manufactured under an approved quality assurance program with follow-up inspections by an inspection agency under ISO/IEC 17020 by a recognized accreditation body conforming to the requirements of ISO/IEC 17011. 13.2—Quality control manuals 13.2.1 For each product assessed in accordance with ACI 355.4M, include a quality control manual complying with a nationally accredited criteria for quality control systems for each manufacturing facility supplying anchors for the marketplace. 13.2.2 Inspections of the manufacturing facility shall be unannounced and shall be conducted quarterly. 13.3.3 Inspections shall assess conformance of ongoing production with the quality control manual on file. 13.3—Special inspection 13.3.1 Special inspection shall be provided in accordance with the building code and ACI 355.4M. For each type of anchoring system, the manufacturer shall submit inspection procedures to verify proper usage. R13.3.1 Special inspection is defined in ACI 318M as a function performed by qualified special inspectors in the employ of the owner or the owner’s agent. A distinction is made between continuous special inspection and periodic special inspection. In the context of anchor installation, continuous special inspection is generally understood to mean that the inspector is present for each anchor installation. 13.3.2 Continuous special inspection—Where required, a program for continuous special inspection shall conform to the following additional requirements. 13.3.2.1 The special inspector shall observe all aspects of the anchor installation with the exception of holes drilled in the absence of the special inspector, provided the special inspector examines the drill bits used for the drilling and verifies the hole sizes. 13.3.2.2 As a minimum, verify the following items: 1. Hole drilling method in accordance with the MPII. 2. Anchor edge distance and spacing. 3. Hole diameter and depth. 4. Hole cleaning in accordance with the MPII. 5. Anchor element type, material, diameter, and length. 6. Adhesive identification and expiration date. 7. Adhesive installation in accordance with the MPII. 13.3.3 Periodic special inspection—Where required, a program for periodic special inspection shall conform to the following additional requirements. The special inspector shall verify the initial installations of each type and size of adhesive anchor by construction personnel on site in accordance with 13.3.2.2. Subsequent installations of the same anchor type and size by the same construction personnel shall be permitted to be performed in the absence of the special inspector. Any change in the anchor product being installed or the personnel performing the installation shall require an initial inspection in accordance with 13.3.2.2. For ongoing installations over an extended period, the special

inspector shall make regular inspections to confirm correct handling and installation of the product. R13.3.3 Periodic special inspection refers to a more intermittent form of inspection with special emphasis on the initial installations. 13.3.4 Proof loading program—Where required, a program for on-site proof loading, that is, proof loading program, to be conducted as part of the special inspection shall be established by the engineer or design professional of record and shall conform to the following minimum requirements. 1. Frequency of proof loading based on anchor type, diameter, and embedment. 2. Proof loads by anchor type, diameter, embedment, and location. 3. Acceptable displacements at proof load. 4. Remedial action in the event of failure to achieve proof load or excessive displacement. Unless otherwise directed by the engineer or design professional of record, proof loads shall be applied as confined tension tests (4.7.3.2). Proof load levels shall not exceed the lesser of 50 percent of the expected peak load based on adhesive bond strength or 80 percent of the anchor yield strength. Maintain the proof load at the required load level for a minimum of 10 seconds. R13.3.4 Proof loading programs are traditionally included in the contract documents to enhance the quality control for safety-related anchor installations. Significant latitude is given to the engineer of record in determining the parameters of the proof load program, which will depend in large part on the type, size, and quantity of anchors being installed. CHAPTER 14—REFERENCES 14.1—Referenced standards and reports The standards and reports listed below were the latest editions at the time this document was prepared. Because these documents are revised frequently, the reader is advised to contact the proper sponsoring group if it is desired to refer to the latest version. American Concrete Institute 318M Building Code Requirements for Structural Concrete and Commentary 355.2 Qualification of Post-Installed Mechanical Anchors in Concrete and Commentary American National Standards Institute B212.15-94 American National Standard for Cutting Tools—Carbide-Tipped Masonry Drills and Blanks for Carbide-Tipped Masonry Drills ASTM International A193/A193M Standard Specification for Alloy Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications C31/C31M Standard Practice for Making and Curing Concrete Test Specimens in the Field


C33/C33M C39/C39M C42/C42M

C150/C150M C618

C881/C881M C882/C882M

D1875 D2556

E488/E488M E1252

E1512 F1080

Standard Specification for Concrete Aggregates Standard Test Method for Compression Strength of Cylindrical Concrete Specimens Standard Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete Standard Specification for Portland Cement Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete Standard Specification for Epoxy Resin Base Bonding Systems for Concrete Standard Test Method for Bond Strength of Epoxy Resin Systems Used with Concrete by Slant Shear Standard Test Method for Density of Adhesives in Fluid Form Standard Test Method for Apparent Viscosity of Adhesives Having Shear Rate Dependent Flow Properties Standard Test Methods for Strength of Anchors in Concrete Elements Standard Practice for General Techniques for Obtaining Infrared Spectra for Qualitative Analysis Standard Test Methods for Testing Bond Performance of Bonded Anchors Standard Test Method for Determining the Consistency of Viscous Liquids Using a Consistometer

International Organization for Standardization (ISO) EN ISO 6988 Metallic and Other Nonorganic Coatings— Sulfur Dioxide Test with General Condensation of Moisture ISO 17011 Conformity Assessment—General Requirements for Accreditation Bodies Accrediting Conformity Assessment Bodies

ISO 17020 ISO 17025

55

General Criteria for the Operation of Various Types of Bodies Performing Inspection General Requirements for the Competence of Testing and Calibration Laboratories

14.2—Cited references ACI Committee 355, 2007, “Qualification of PostInstalled Mechanical Anchors in Concrete (ACI 355.2-07) and Commentary,” American Concrete Institute, Farmington Hills, MI, 31 pp. ACI Committee 318, 2008, “Building Code Requirements for Structural Concrete (ACI 318M-08) and Commentary,” American Concrete Institute, Farmington Hills, MI, 473 pp. ANSI/ASME B1.1, 1989, “Unified Inch Screw Threads (UN and UNR Thread Form),” ASME, Fairfield, NJ, 188 pp. Cook, R. A., and Konz, R. C., 2001, “Factors Influencing Bond Strength of Adhesive Anchors,” ACI Structural Journal, V. 98, No. 1, Jan.-Feb., pp. 76-86. Eligehausen, R.; Cook, R.; and Appl, J., 2006, “Behavior and Design of Adhesive Bonded Anchors,” ACI Structural Journal, V. 103, No. 6, Nov.-Dec., pp. 822-831. Eligehausen, R.; Mattis, L.; Wollmershauser, R.; and Hoehler, M., 2004, “Testing Anchors in Cracked Concrete,” Concrete International, V. 26, No. 7, July, pp. 66-71. Fuchs, W.; Eligehausen, R.; and Breen, J., 1995, “Concrete Capacity Design (CCD) Approach for Fastening to Concrete,” ACI Structural Journal, V. 92, No. 1, Jan.Feb., pp. 73-94. Spieth, H.; Ozbolt, J.; Eligehausen, R; and Appl, J., 2001, “Numerical and Experimental Analysis of Post-Installed Rebars Spliced with Cast-in-Place Rebars,” Proceedings of International Symposium on Connections between Steel and Concrete, Stuttgart, Germany, 1448 pp. Zamora, N. A.; Cook, R. A.; Konz, R. C.; and Consolazio, G. R., 2003, “Behavior and Design of Single, Headed, and Unheaded Grouted Anchors under Tensile Load,” ACI Structural Journal, V. 100, No. 2, Mar.-Apr., pp. 222-230.

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Qualification of Post-Installed Adhesive Anchors in Concrete (ACI 355.4M-11) and Commentary

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ACI 355.4M-11 - Qualification of Post-Installed Adhesive Anchors in Concrete and Commentary (Metric)

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