1、ACI 437.1R-07Load Tests of Concrete Structures:Methods, Magnitude, Protocols,and Acceptance CriteriaReported by ACI Committee 437American Concrete InstituteAdvancing concrete knowledgeLoad Tests of Concrete Structures:Methods, Magnitude, Protocols, and Acceptance CriteriaFirst PrintingMarch 2007ISBN
2、 978-0-87031-233-5Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This materialmay not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or otherdistribution and storage media, without the written consent of ACI.The tech
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10、crete Practice (MCP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgACI 437.1R-07 was adopted and published March 2007.Copyright 2007, American Concrete Institute.All rights reserved including rights of reproduct
11、ion and use in any form or by anymeans, including the making of copies by any photo process, or by electronic ormechanical device, printed, written, or oral, or recording for sound or visual reproductionor for use in any knowledge or retrieval system or device, unless permission in writingis obtaine
12、d from the copyright proprietors.437.1R-1ACI Committee Reports, Guides, Standard Practices, andCommentaries are intended for guidance in planning,designing, executing, and inspecting construction. Thisdocument is intended for the use of individuals who arecompetent to evaluate the significance and l
13、imitations of itscontent and recommendations and who will acceptresponsibility for the application of the material it contains.The American Concrete Institute disclaims any and allresponsibility for the stated principles. The Institute shall notbe liable for any loss or damage arising therefrom.Refe
14、rence to this document shall not be made in contractdocuments. If items found in this document are desired by theArchitect/Engineer to be a part of the contract documents, theyshall be restated in mandatory language for incorporation bythe Architect/Engineer.Load Tests of Concrete Structures: Method
15、s, Magnitude, Protocols, and Acceptance CriteriaReported by ACI Committee 437ACI 437.1R-07This report provides the recommendations of Committee 437 regardingselection of test load magnitudes, protocol, and acceptance criteria to beused when performing load testing as a means of evaluating safety and
16、serviceability of concrete structural members and systems. The history ofload factors and acceptance criteria as found in the ACI 318 building codeis provided along with a review of other load test practice. Recommendedrevisions to load factors to be used at this time, additions to load testingproto
17、col, and revisions to acceptance criteria used to evaluate the findingsof load testing are provided.Keywords: acceptance criteria; cyclic load test; deflection; deterioration;load test factors; load test protocol; monotonic load test; reinforcedconcrete; strength evaluation.CONTENTSChapter 1Introduc
18、tion, p. 437.1R-21.1Background1.2Introduction1.3LimitationsChapter 2Notation and terminology, p. 437.1R-32.1Notation2.2TerminologyChapter 3History of load test, load factors, and acceptance criteria, p. 437.1R-43.1Scope of historical review3.2Summary and conclusionsChapter 4Load factors, p. 437.1R-5
19、4.1Introduction4.2Load factors for various components of service load4.3Load factors for extreme ratios of live load to totaldead loadTarek Alkhrdaji Ashok M. Kakade Javeed Munshi Thomas Rewerts*Joseph A. Amon*Dov Kaminetzky Thomas E. NehilK. Nam ShiuNicholas J. Carino Andrew T. Krauklis Renato Parr
20、etti Avanti C. ShroffPaolo Casadei Chuck J. Larosche Brian J. Pashina Jay ThomasUfuk Dilek Michael W. Lee Stephen Pessiki Jeffrey A. TravisJohn Frauenhoffer*Daniel J. McCarthy*Predrag L. Popovic Fernando V. UlloaZareh B. Gregorian Patrick R. McCormick Guillermo Ramirez*Paul H. Ziehl*Pawan R. Gupta M
21、atthew A. Mettemeyer*Member of subcommittee that prepared this report.Chair of subcommittee that prepared this report.Antonio Nanni*ChairJeffrey S. WestSecretary437.1R-2 ACI COMMITTEE REPORTChapter 5Load test protocol, p. 437.1R-105.1Introduction5.2Test load configuration5.3Load application method5.
22、4Loading procedures5.5Loading duration5.6Load testing procedureChapter 6Acceptance criteria, p. 437.1R-136.1Criteria for 24-hour monotonic load test6.2Criteria for cyclic load test6.3Considerations of performance assessment at serviceload level6.4Recommendations for acceptance criteria at test loadm
23、agnitude level6.5Strength reserve beyond load test acceptance criteriaChapter 7Summary, p. 437.1R-17Chapter 8References, p. 437.1R-178.1Referenced standards and reports8.2Cited referencesAppendix ADetermination of equivalentpatch load, p. 437.1R-19A.1NotationA.2IntroductionA.3One-way slab systemA.4P
24、rocedure and preliminary calculationsA.5Calculations after calibration cycleA.6ConclusionsAppendix BHistory of load test, load factors, and acceptance criteria, p. 437.1R-23B.1NotationB.2Historical load test practice in the United States andaccording to ACIB.3Other historical load test practicesCHAP
25、TER 1INTRODUCTION1.1BackgroundSignificant revisions were made in Chapter 9 of ACI 318-02to the load factors to be used for determining requiredstrength. The load factor for dead load was reduced from 1.4to 1.2, and the load factor for live load was reduced from 1.7to 1.6; other changes were also mad
26、e as given in equationsfor required strength in Chapter 9. The strength-reductionfactors (-factors) were also modified. The -factor for shearand torsion was reduced from 0.85 to 0.75, while the -factorfor compression-controlled members was reduced from 0.70to 0.65 unless spiral reinforcement is prov
27、ided. The -factorfor tension-controlled members (most flexural members)was not reduced, and remains 0.9.The load factors and load combinations of ACI 318-05match those of ASCE 7-02 (American Society of Civil Engi-neers 2002). The changes were made to unify the load factorsused to design concrete str
28、uctures with those generally usedto design structures constructed of other materials, such asstructural steel. The changes also facilitated the design ofconcrete structures that included members of materials otherthan concrete.Chapter 20 (Strength Evaluation of Existing Structures) of318-02 and 318-
29、05 was not changed from the previous codewith regard to load test procedures. Section 20.3.2 (LoadIntensity) of ACI 318-02 was not changed from the 1999edition; that is, the total test load (including dead loadalready in place) was still defined to be not less than0.85(1.4D + 1.7L), with live load p
30、ermitted to be reduced inaccordance with the applicable building code.The reduction in load factors used for computing requiredstrength without a corresponding reduction in the test loadintensity resulted in two effects. First, the test load was nolonger a fixed percentage of the required strength.
31、Second,the test load was now in the range of 93 to 98% of therequired strength for tension-controlled sections rather than85% of the required strength as was the case in ACI 318-71through 318-99.ACI Committee 318 requested that Committee 437 reviewand report on the load intensity requirements of Cha
32、pter 20.In the process, Committee 437 has undertaken a thoroughreview of the historical background of load testing anddeveloped not only recommendations for revisions to the testload magnitude (TLM), but also to the protocol for loadtesting and the acceptance criteria used to evaluate the results.1.
33、2IntroductionThe provisions of Chapter 20 of ACI 318 have remainedessentially unchanged for an unprecedented period of timesince the publication of ACI 318-71, when the code waschanged from working stress design to ultimate strengthdesign. Before the 1971 code, the test load requirements oracceptanc
34、e criteria were revised with almost every newedition of the code dating back to 1920. Chapter 3 andAppendix B of this report provide a detailed review of thehistory of the load test requirements and acceptance criteriain ACI 318. They also provide a discussion of other interna-tional standards and o
35、f significant research and reporting ofother organizations on the subject of load testing.The changes made in the load factors and load combina-tions of ACI 318-05 require a re-examination of the load testrequirements of Chapter 20 of ACI 318-05. This reportpresents the recommendations of Committee
36、437 for revisionsto the requirements of Chapter 20. Three key areas areaddressed: load factors to be used in defining the TLM; theload test protocol; and acceptance criteria.As will be discussed further in Chapter 4, the purposes ofthe recommended revisions to the TLM definition are twofold.The firs
37、t purpose is to define a test load that will demonstratea consistent safe margin of capacity over code-requiredservice live load levels. Secondly, the definition of the testload primarily in terms of service live load rather than required(ultimate) strength is meant to emphasize the fact that loadte
38、sting is (typically) a proof loading. In the experience of thecommittee members, most structures being load tested passwith small deflections. Load testing does not typically providean indication of the ultimate strength of the structure, and thatindication usually is not the goal of load testing.LO
39、AD TESTS OF CONCRETE STRUCTURES 437.1R-3Since 1920, the acceptance criteria used with load testinghave incorporated a limit on measured maximum deflectionsafter a 24-hour holding period of the total test load. Thecurrent criteria have not changed since ACI 318-63.Currently, the deflection limit is d
40、escribed by the formulamax lt2/20,000h. The theoretical basis for this formula hadits origins in the first decades of the 20th century. Thecommittee has researched the origins of the formula and re-evaluated its appropriateness. The committee recommendsadopting other more meaningful deflection accep
41、tance criteria.Chapters 5 and 6 of the report discuss selection of a loadtest protocol and recommended changes to the acceptancecriteria used in strength evaluation and load testing.Committee 437 in its report 437R-03, “Strength Evaluationof Existing Concrete Buildings,” has discussed a cyclic loadt
42、est method that offers advantages in terms of reliability andunderstanding of structural response to load when comparedwith the conventional static load test. Chapter 6 presentsrecommended acceptance criteria for both the 24-hour statictest and for the cyclic test. Acceptance criteria for service-ab
43、ility are also given.1.3LimitationsProcedures and recommendations provided in this reportare intended for structures and buildings using concretes ofnormal strengths. The methods are not intended for bridges,structures with unusual design concepts, or other specialstructures. The methods are not int
44、ended to be used forproduct development testing where load testing is used forquality control or approval of mass-produced members. Testingfor resistance to wind and seismic loads is not discussed.AASHTO provisions for load testing of bridge structures areoutside the scope of this report. Load testi
45、ng to determineultimate strength is also outside the scope of this report.CHAPTER 2NOTATION AND TERMINOLOGY2.1NotationThe notations reported in this section refer to the symbolsused in the numbered chapters.h = overall thickness of member, in. (mm)lt= span of member under load test; units depend ons
46、tructural member considered (ACI 318)s = average spacing between cracks, in. (mm)D = total dead load: Dw + Ds; units depend onstructural member consideredDs= superimposed dead load; units depend on structuralmember consideredDw= dead load due to self-weight; units depend onstructural member consider
47、edF = loads due to weight and pressure of fluids withwell-defined densities and controllablemaximum heights; units depend on structuralmember consideredIDL= deviation from linearity index, dimensionlessIP= permanency index, dimensionlessIR= repeatability index, dimensionlessL = live loads produced b
48、y use and occupancy of thebuilding not including construction, environ-mental loads, and superimposed dead loads; unitsdepend on structural member consideredLr= roof live loads produced during maintenance byworkers, equipment, and materials or during lifeof structure by moveable objects such as plan
49、tersand people; units depend on structural memberconsideredP=applied load during load test (Fig. 6.1 and 6.2)Pi= load of point i in load-deflection envelope forcomputation of IDLacceptance criterion (Fig. 6.2)Pmin= minimum load to be maintained during load test(typically 10% of total test load) Pref = reference load for computation of IDLacceptancecriterion (Fig. 6.2)R = rain load, or related internal moments and forces;units depend on structural member consideredS = snow load; units depend on structural memberconsideredTL = test load
