ACI-364.1R-07-9780870312458-CivilEA.com

ACI 364.1R-07 Guide for Evaluation of Concrete Structures before Rehabilitation Reported by ACI Committee 364 First Printing May 2007 ® American Concrete Institute Advancing concrete knowledge Guide for Evaluation of Concrete Structures before Rehabilitation 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 occa- sionally 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. 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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 regula- tions, including but not limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards. 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). American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 U.S.A. Phone: 248-848-3700 Fax: 248-848-3701 www.concrete.org ISBN 978-0-87031-245-8 or oral. condition survey. or for use in any knowledge or retrieval system or device.2—Design information 1. or recording for sound or visual reproduction the Architect/Engineer. Spencer Michael L. This 4. evaluation. detailed investigation. Shewmaker David W. p. McGovern David A. printed.1—Introduction 3. and inspecting construction. Brown Robert L. and Chapter 4—Field investigation.9—Report CONTENTS Chapter 1—Introduction. distress.4—Condition survey and visual inspection responsibility for the application of the material it contains. Reference to this document shall not be made in contract ACI 364.3—Preliminary investigation investigation. Von Fay Boris Dragunsky Lawrence F. including the making of copies by any photo process. Heffron Pritpal S. Kahn Mark A. Whitmore Timothy R. unless permission in writing is obtained from the copyright proprietors.3—Field verification of as-built construction content and recommendations and who will accept 4.1—General 3. The American Concrete Institute disclaims any and all 4.4—Construction information Chapter 2—Preliminary and detailed investigation. Hookham William R. documents. 4. Evaluation to identify seismic deficiencies is beyond the scope of 2. Kesner K. Vaysburd Chair Secretary Sam Bhuyan Zareh B. Scott Patrick M.1R-07 Guide for Evaluation of Concrete Structures before Rehabilitation Reported by ACI Committee 364 Fred R. Gregorian Erick N. Standard Practices.8—Evaluation 2. deterioration. 364. Shroff Benoit Bissonnette Pawan R. p. rehabilitation. Postma James Warner Peter H. 2. ACI 364. they means. Goodwin Alexander M. or by electronic or shall be restated in mandatory language for incorporation by mechanical device. 364. sampling.2—Definitions 3.1R-7 1.4—Detailed investigation report.1R-2 Chapter 3—Document review.5—Unsafe or potentially hazardous conditions responsibility for the stated principles.5—Service history 2. Gillespie Keith E.3—Materials information 3. Nash Kurt F. McDonald Valery Tokar Douglas Burke Kal R. Among the subjects covered are: preliminary 2. VanOcker Ashok K.1R-94 and was adopted and published May 2007. 364. documentation.6—Project documents ACI Committee Reports.1R-8 Commentaries are intended for guidance in planning.1—Introduction designing. American Concrete Institute. Tanner Christopher D.1R-3 3. sampling and material testing. Nam Shiu This guide presents general procedures for evaluation of concrete structures 2. 2.1R-07 supersedes ACI 364. field observation and condition survey.3—Purpose and scope 3.6—Field investigation 2. Guides.1R-1 . Gupta James L. Gaudette Dov Kaminetzky Robert E. If items found in this document are desired by the Copyright © 2007. Loper Thomas E. and final 2. 364.7—Sampling and material testing Keywords: concrete. Emmons Ashok M. testing. evaluation. The Institute shall not be liable for any loss or damage arising therefrom.5—Document review this report. Henry James E.1—Introduction 1. Kakade David W. p. Hindo Martin S. Mangat John A. written.2—Investigation: overview before rehabilitation. 364. p. All rights reserved including rights of reproduction and use in any form or by any Architect/Engineer to be a part of the contract documents.2—Preparation and planning document is intended for the use of individuals who are competent to evaluate the significance and limitations of its 4. Larson Avanti C. Dhingra Charles J. W. investigation. executing. Watson Paul E. Brainerd Ronald E. 1—Introduction observed in rehabilitation projects due to erroneous reha- 7. 364. unusual loadings. form. and other forces. (a) To assess deterioration due to exposure conditions. 7. (e) To enlarge a structure or change the appearance of the The following terms are defined herein for the purpose of structure. such as interference with normal operations or a 5. including gravity (g) To verify the structural adequacy and integrity of a frames. structure or selected elements within a structure. weathering. (d) To assess the capacity of a structure to accommodate strength—the ability of a material to resist strain or larger loads. or inadequate restoration—the process of re-establishing the materials. moment-resisting frames. can easily exceed those of 5. walls.2—Dimensions and geometry or that have been damaged by a physical event.1R-11 with items. The agencies performing tests of the materials should be experienced in the testing and testing Chapter 8—References.1R-14 existing structure. rupture induced by external forces. 364. to proceed with the rehabilitation work. poor construction. 364. it may established record in completing similar rehabilitation projects.1—Introduction deteriorated due to prolonged exposure to the environment. however.6—Evaluation work and possessing necessary registration with the applicable 7. The technicians 8.2—Cited references is equally important to retain services of an experienced specialty contractor to provide better cost estimates. fatigue effects.3—Testing and evaluation often be planned and executed with minimal interference 5. as applicable to the tests. flood.1—General work. It 8.5—Sampling and material testing results such as design professionals. costs for various levels of interference during the evaluation condition assessment—conclusions based on engineering process so that an informed decision can be made as to how judgment about the condition of a structure. p. p. Although rehabilitation can 5.2—Purpose and scope of investigation bilitation procedure and or improper judgment. 364. If competitive bidding is used. fire. These procedures are intended to be 1. Guidance for 6.5—Cost evaluation Engineering judgment and close consultation with the owner 6. slabs. rehabilitation—the process of repairing or modifying a (b) To evaluate structural damage or distress resulting from structure to a desired useful condition. it is essential to retain the services of consultants. improper design. and the difficulty of 1. particularly in structures that have 6. and diaphragms.2—Definitions used as a guide to assist the architect/engineer responsible The following definitions are defined herein as in ACI 116R: for the evaluation.3—Documentation recovered to support evaluation Due to the many unknowns inherent in evaluating existing 7. also be useful for evaluation of structures even if rehabilitation is not contemplated.2—Determination of testing requirements the actual rehabilitation work. . ties.1R-15 7. foundation settlement. repair—to replace or correct deteriorated.6—Evaluation of rehabilitation alternatives regarding the intended use of the structure are required in the evaluation of structures. experienced in this type of 7. it is usually more cost effective to 5.364. faulty materials. a structure. is provided in ACI 318. or elements of a structure. including beams. clarification and used throughout the balance of this report: (f) To determine the feasibility of modifying an existing assembly—components of a structure that act together to structure to conform to current codes and standards. and resist gravity.4—Field observations and condition survey structures. Many repair failures have been Chapter 7—Final report. The objective and extent of the rehabilitation effort should component—the basic structural members that constitute be clearly defined. abrasion. There is no absolute measurement of structural safety in an Chapter 6—Evaluation. Strength Evaluation of Existing Structures. shearwalls. 7. 6. braced frames. p. 6.4—Test methods with normal operations. and appearance of a structure to those of a particular (c) To determine the feasibility of changing the use of a era of the structure. 6. columns.5—Sampling techniques cease normal operations during rehabilitation work.1R-16 procedures and accredited. maintenance.1—Introduction complete shutdown of a structure.4—Structural evaluation Chapter 20.1R-2 ACI COMMITTEE REPORT Chapter 5—Sampling and material testing. The cost associated p. if applicable. lateral.1—Referenced standards and reports should be certified in their field. however. evaluate CHAPTER 1—INTRODUCTION the level of disturbance to the users. chemical attack.7—Findings and recommendations state licensing board. or overloads. The evaluation work is generally preservation—the process of maintaining a structure in its performed for one or more of the following purposes: present condition and arresting further deterioration.3—Materials evaluation the strength evaluation. thereby providing focus for the evaluation. components. consideration should be This report outlines procedures for the evaluation of given to limiting bidding to prequalified contractors with an concrete structures before rehabilitation. damaged. and The owner should be consulted and provided with relative piers. structure. Chapter 3 a structure’s behavior. the owner’s needs and 1. drawn from publications. identifiable part of a structure. and nondestructive tests. or strengthening. Guidelines for preparing laboratory tests to determine material or structural properties the final report are presented in Chapter 7. and investigation may be needed. dams. either in the field or laboratory. the preliminary to rehabilitate an existing structure. or INVESTIGATION other structural system. Evaluation of specialty structure properly evaluate the concrete structure. tests. stating the objectives and the This guide presents recommendations based on experience scope of work. though the the owner and design professional contracted to perform the concepts are similar. Reporting. testing. EVALUATION OF CONCRETE STRUCTURES BEFORE REHABILITATION 364. nuclear power plants. interpretation of data interviews with persons knowledgeable of the structure. and a more detailed types. or intended function. evaluation is recommended. The first and the most important rehabilitation alternative. considered to be concrete in this 2. condition. Due to rehabilitation. are beyond the scope of this report. Document review. identification and evaluation of components from the structure for the purpose of conducting rehabilitation alternatives. Preliminary and detailed investigations often contain Investigations generally involve three major tasks: locating varying levels of some or all of the following items: and reviewing pertinent documents.1 identifies methodology and major tasks that are 4. Sampling and material testing. but specific will directly influence the final outcome of the evaluation enough for use as a model evaluation procedure for a structure. the experience and judgment of the design professional. and the need for identifies those documents and sources of information that preservation. 1. feasibility of performing the intended rehabilitation. principally by visual inspection and in those cases.1R-3 condition survey—quantitatively defining the physical In some cases. past investigations. information regarding a structure’s behavior. As a result. The nondestructive or destructive. performing field 1. hidden or unexpected is a substantial difference between the complexity of design conditions may be discovered. Field investigation. and references are or to further quantify physical condition. acceptance criteria for material sampling—identifying and removing materials or and structural evaluations. Before beginning the investigation. CHAPTER 2—PRELIMINARY AND DETAILED structure—the building. evaluation and analysis can be completed and a final report prepared. The goal of an investigation is to provide information testing—quantifying material or physical properties of the regarding the existing condition of a structure. condition of a structure. The flowchart 3. before rehabilitation. the estimated cost associated with each would normally be conducted. integrity. and field and laboratory destructive strength. rehabilitation. The findings of the preliminary and detailed investigations The guidelines provided are general in character. the selection of the single effort in evaluation before rehabilitation is the appropriate rehabilitation method. compared with the investigation may not provide enough information to design of a new structure. in Fig. and ultimately. Evaluation. damage. or distress present. surveys. element—a separate. Chapter 5 provides information on practices and procedures investigation—collecting and assembling data and detailed for sampling and material testing. and other means. destructive testing often investigation should also allow the owner to evaluate the requires follow-up repair. and costs. including review of observations and tests. and commonly undertaken in an investigation. strengthening—increasing the load-resistance capacity of a structure or portion thereof. included in Chapter 8. preliminary investigation. such as bridges. components of a building. Chapter 2 of this report defines the attributes and uses of evaluation—using the results from investigations and both preliminary and detailed investigations in the evaluation structural engineering principles to derive conclusions regarding process and provides an overview of the report. A written agreement between tunnels. Chapter 6 discusses the evaluation. condition. and extent of deterioration. performance. obtained from investigations. such as conducting the accumulated information and data. the pertinent documentation is not available. After completion of the preliminary investigation. the choices of various rehabilitation methods to This report is presented in the order in which an evaluation be considered.3—Purpose and scope The purpose of this guide is to provide general procedures expectations should be evaluated to determine whether a for the evaluation of concrete building structures before preliminary or detailed investigation is appropriate. and sampling and material 2. Testing may be the structure’s behavior. and evaluations. observations and condition surveys. acquired from analyses of documents. restoration. This is of particular importance because there the nature of any investigation. including visual inspection. From the investigation results. as described in Chapter 2. 5. process. The inspection—the process of using aided and unaided visual efforts required in performing field observations to verify techniques to ascertain the physical condition of a structure and survey the structural condition are described in Chapter 4. would normally be reviewed during the evaluation. the detailed 2.1—Introduction guide unless otherwise noted.2—Investigation: overview investigation can proceed if deemed desirable or necessary. It should identify structure through the use of testing procedures and calibrated the type and seriousness of any apparent conditions affecting equipment. . the success of the evaluation is dependent on supplemented by nondestructive tests. 3—Preliminary investigation A preliminary investigation should. at a minimum. field observation.4—Detailed investigation of severe damage where the structural integrity cannot be A detailed investigation is performed when the initial site economically restored or where it becomes obvious that the visit or preliminary investigation has identified a need for a owner’s objectives cannot be satisfactorily met. If a preliminary investigation was to more thoroughly evaluate the concrete structure. temporary shoring or where minimal distress or unusual conditions exist. Preliminary investigations cation of the investigation strategy.1—Evaluation methodology. conducted that led to the need for a detailed investigation. and existing and known sources. preliminary investigation may determine that it is undesirable to proceed with a further detailed investigation. modifi- the established objective. it is .1R-4 ACI COMMITTEE REPORT Fig. where extensive documentation indicate severe distress. A preliminary investigation documents. Preliminary investigations are general and rehabilitation objectives. and supplemental technical commonly recommend the need for a detailed investigation and economic analyses. the owner should be immediately on the construction and maintenance of the structure exist. In the event that the observations the same or similar loadings. The detailed investigation may in nature. more in-depth assessment of the concrete structure’s A preliminary investigation is not intended to be a behavior or condition to meet the owner’s goals for the work comprehensive study. as in the case 2. condition. and measurements of performance based on an established objective or reason for the structure to survey for condition and conformance to performing the rehabilitation. as a minimum. and may not be comprehensive enough to achieve include additional assessment of concrete structure. The preliminary investigation develops an initial assessment include acquisition of available documents from the owner of the concrete structure’s behavior.364. The stabilization of the observed component experiencing distress. 1. 2. or contacted to provide. and local sampling or testing if found needed may be sufficient when the proposed usage changes involve (Chapters 3 through 5). information. Initial impressions often accurately system and its condition. photographic record of this condition is essential. or other records includes checking of critical design details. and exploratory openings. material sampling and testing. a resources for obtaining construction documents. columns. should use experienced structural engineers for further previous investigation reports.7—Sampling and material testing during the field investigation. needed for various types of structures and where such Frequency. specifications. Universities. implications to changing load paths or the behavior of the and objectives before beginning the detailed investigation. extent. physical properties can be guidelines for field observation and condition survey are determined from sampling and testing. As the document review progresses. Field survey record drawings In addition to field observation. Where turers. owner should be notified immediately. support regions. ACI 207. documentation may be obtained. attention should be Especially when older structures are involved. A thorough review of the the structure may be adequate to establish the project scope available documentation will save both time and cost for any and to define the project needs. characterize the nature of a problem. it may be necessary to provide essential information on structural features such as employ nondestructive tests on components of the structure perimeter boundaries.1 Nondestructive testing—Nondestructive testing each floor. 2. information on the conditions and problems observed in the cies. In such a case. construction materials. field observation is required to verify reliability Critical data. or other related information. or large subcontracting companies are other possible unusually severe deterioration or distress is observed. beams. or possible changes in structure use since information for decisions regarding further testing and its original construction should be developed during the evaluation (ACI 228. and need for follow-up and appropriate remedial actions should making detailed documentation of the existing structural be documented in a report. Testing agen. one record document sheet may be developed for 2. load paths. such as loading requirements. the study should begin with special steps to throughout the structure should be recorded. are suspected. A walk-through of documents relating to the structure. specifications. construction records. If structural problems. and designers. Subsequent monitoring of movements. investigation and evaluation. precast concrete manufac. construction records. building management firms. The from the available documentation. and state preservation offices may When serious distress or deficiencies are discovered that have design documents. cracks. Field notes. the design professional plans. original concentrations occur.2R). For rehabilitation projects. and the loads to which it is subjected. The owner’s files. For example. alterations. A list of items or questions concerning as-built supplements visual observations. Field observations should serviceability. and other construction temporary evacuation. can be used to locate reinforcement as an alternative to Alterations to in-service structures are commonly made. field (ACI 201. If such information is not available its environment. should be reviewed. shop drawings. Sometimes it is necessary to search many sources to obtain such as distress. structure. and can yield valuable status. libraries. historic societies. These can be compared with Even with complete documentation and construction current applicable codes and standards to determine margins. supplemental written agreement stating the objectives and the scope of the detailed investigation is recommended. and original contractors are generally the best videos are valuable aids in classifying and communicating sources to search for documents and records. Nondestructive tests. Applicable code requirements at the time of the design should be checked. Buchanan 1983). In general. but also the present condition of the structure. owner. city or library archives. It is often necessary to not only address the as-built geometry and materials of determine the in-place physical properties of the existing construction. When original documents deterioration. and photographs may result in unsafe or potentially hazardous conditions. field survey drawings should be developed for recording information obtained 2. A review of the plans. evaluation and follow-up rehabilitation project. A entire structural system. however. capacity. more detailed checks of various items and close provides further guidance on the type of documentation examination of representative or typical areas are warranted. photographic records. and severity of problems (for example. and wall locations or in-place materials to investigate their condition and and dimensions. and elements. compensate for the missing information. should should be carefully noted and evaluated for potential be correlated with testing of samples or exploratory openings . and the presence of any unusual progressive distress may be needed. distress. areas of abrupt documents can consume far more time than the actual geometric change. expectations. EVALUATION OF CONCRETE STRUCTURES BEFORE REHABILITATION 364.1R-5 important to re-evaluate the owner’s needs. given in Chapter 4. temporary shoring measures. and areas in the structure where load review.1R. obtain. Chapter 3 however. Steps may include Assessment of the observed conditions and identifying the nondestructive testing.3R. and review the pertinent and the related components or elements. obtaining given to connections. nondestructive tests record review process then cross-checked in the field. or nonconformity to documentation) are unavailable.6—Field investigation An investigation generally documents the nature and 2. If the structure being examined is a multifloor strength or to take samples for laboratory tests. features. the of historic structures.7.5—Document review extent of observed conditions and identifies any problems It is important to locate. and and accuracy of these documents. and emergency safety measures should be recommended to the understanding the arrangement of critical components. the identified structural problems and to determine whether hardness. In such cases. or the use of inspection openings are often deferred to the 4. to conduct a more detailed investigations. of the construction materials can be obtained through 2. alkali-aggregate reaction). and structural load testing (in-place). to proceed and destructive testing are required as part of detailed with the rehabilitation project. 2. material sampling and 4. accepted engineering principles. field 3. Exploratory openings help to determine 2. and prestressing steel (preten. The structural capacity check generally 2. procedures is included in Chapter 5 of this report and in ACI and engineering assumptions (such as those illustrated in 228. usually only select areas of a structure are ening requirements. impulse. or other readily obtainable samples frequently identifies conditions that may be in marginal for compressive strength testing (ASTM C 42/C 42M). The structure or individual components are adequate for existing as-built features and to gain reliable information the existing service loads. should be notified of mechanical properties (for example. if not identified in the on technical and cost considerations should determine whether construction documents or by observations. small sawed specimens. When structural or material problems are identified. Sound testing (hammer testing or chain-drag) to locate shallow delaminations.8. Some of the most the methods of sampling that may be performed during the common techniques used during preliminary investigation are: investigation. ACI 437R). tested.1 Structural capacity check—A structural capacity response. impact-echo. Selective inspection openings are also used to verify the results of 3. Rebound hammer to estimate compressive strength. and may be the structural problem and the corrective actions required. but are not adequate for intended use.2R. When needed soil or foundation include the expected effectiveness of the rehabilitation.7. the Material testing is often required to determine the existing owner. identification of structural distress. A description of available nondestructive test methods and results of the investigation. The check is inconclusive. During the preliminary investigation. radiography. 1.8. The investigation is subsequently required to identify the extent of testing may be destructive or nondestructive. or possibly the local authorities. life-cycle cost. During a preliminary structural capacity check. The status of reinforcing steel. and others.2 Feasibility of rehabilitation—An assessment based sampling and laboratory testing. and observations and condition survey. information is missing. material deterioration. verification of physical be considered in reaching a conclusion regarding feasibility properties is recommended. Steps should be taken to verify the significance of taken and tested to determine properties such as yield strength. determination should be made regarding the adequacy of the 2. Reinforcing steel samples may be ration. about the nature and extent of existing problems. Detailed investigations may use more extensive investigation. or to choose an alternative plan. check is based on the construction documents obtained. testing.7. and needs for further investigation. compliance with or in violation of current building codes. and maintenance require- may also be necessary. in a structure. Chapter 5 describes the types of testing and condition affecting occupant safety or stability of the structure. test methods such as pulse velocity.8—Evaluation 2. especially for older structures. Measuring of half-cell potentials to determine corrosion testing) are considered in the evaluation of the structure. It performed either in the field with portable equipment or in may be necessary to propose immediate action to deal with a the laboratory. 2. and determination of chloride-ion content as a function of along with the steps required to remedy the distress or deterio- sample depth from surface. Even when a proposed rehabilitation option is feasible. Based on the results. In many cases.1R-6 ACI COMMITTEE REPORT to confirm their reliability (ACI 437R). strength- investigation. When operation of the facility should also be considered. . excavation and testing of soil properties estimated service life.2 Exploratory removal and openings—Exploratory produces one of four conclusions: removal of material and creating openings are useful to 1. sampling generally consists of extracting a 2.364. The effects of the rehabilitation on the structural system Extensive sampling and laboratory testing is usually not and the anticipated functional and economic impact on the performed during the preliminary investigation. evaluation should address the need for rehabilitation and It is unlikely that all of these methods will be used during feasibility of options. problems that require immediate action.8. a single preliminary investigation. petrographic examination (ASTM C 856). Points that should construction documents are available. immediate action is required to ensure the safety or protection sioned strands or bars or unbonded post-tensioning tendons) of the structural system. ments.3 Structural distress or material deterioration— representative number of concrete cores (ASTM C 42/C 42M). The results of an investigation (document review. It is not unusual to encounter may be carefully removed to assess mechanical properties. a detailed condition (for example. loads or serving the intended use. they Powder samples may also be extracted for chemical analysis should be described in terms of their seriousness and extent. strength) and physical the immediate actions needed. Preliminary investigation. and carbon content. and analysis—Physical properties structure and actions to be taken. Cover meters to locate reinforcing steel. a detailed investigation phase. The structure or its individual components are adequate determine as-built conditions and to expose hidden conditions for the intended use. performed. The structure is not adequate for resisting expected nondestructive tests. The results of this testing often help identify locations Chapter 6 identifies elements that should be evaluated to within a structure where more comprehensive nondestructive reach a conclusion to leave the structure as-is.3 Sampling. should be clearly stated. individual. report may also include an action plan.2. structure is a structure that is at least 50 years old and is HABS (U. Local building departments’ records may be valuable in locating alteration plans and other related 2. investigation. An historic 4. Department of Interior 2007) has drawings associated to a significant historic event or significant and reports on many historic buildings (McKee 1970).2. 3. Guidelines for preparing the final report are relate the structural system used in the project to the design included in Chapter 7. submittals. Often. Frequently.1 Nonhistoric structures—Documents that may requirements are not fully addressed in a preliminary contain useful information include: investigation. information. In some cases. The final report should include the design historic structures on multiple levels—federal. patents. Before performing an evaluation of a concrete structure.S. For the purposes of this guide. State and local historical society records. specifications. and repair reports. strengthening 3. the (j) Design and applicable age-appropriate building codes. options. addenda. 2. field and test data. cost estimates.2 Historic structures—Buildings may be designated as methodology. The nature (c) Placing drawings of concrete reinforcement. the subcontractors. (h) Textbooks written at the time of design. but the preliminary or detailed investigation. various strengthening (a) Design drawings. required to satisfy these objectives. and tentative design and construction When working on historic structures. if required. and correspondence. If required. rehabilitation rigid rules need to be carefully studied and followed. (d) Alteration plans. and change orders.9—Report records (such as inspection reports or violation notices).8.5 Further investigation—The need for a further (i) Previous maintenance. The the extent of required preservation and rehabilitation.8. Documents that may contain useful information for historical itated will dictate the nature and quantity of information structures are similar to those noted previously for nonhistoric that should be reviewed. each strengthening method considered should be compared. or professional’s conclusions and any recommendations to the local—with each entity establishing their own restrictions on owner on how to proceed with rehabilitation. of the strengthening. As a result. 1. rehabilitation project and the type of structure being rehabil. Actions taken to strengthen existing (e) As-built drawings. cost and time anticipated for the detailed for the governmental entity in which the structure is located. strengthening the existing structural components or (g) Manufacturer’s technical information. Both capital cost and future maintenance costs for construction materials. and as nonhistoric structures and historic structures. including the it is extremely important for completion of the evaluation listing of available existing documentation for the structure. along with the following additional documents: found and a detailed investigation will be necessary. The The final report should include the results of all phases of assembly of all this information can be time-consuming. Not only were design calculations often presented in tabular uation of concrete structures before rehabilitation. field observations. or design. state. Historic photographs. end product of a preliminary investigation is the determination Information regarding original construction or alteration that a detailed investigation is required. practices existing at the time of construction. research of all pertinent information should be performed. local building departments or regulatory agencies objectives. The investigation should also (f) Applicable building code(s) at the time of original consider the cost effectiveness of repairing. on many older structural designs. addenda. there is a substantial amount CHAPTER 3—DOCUMENT REVIEW of available information. the architect or addressed in planning the next phase of the work include the engineer. and subsequent success of the rehabilitation project. methods should be considered to satisfy the intended loading (b) Shop drawings.2—Design information 2. This review form. and (detailed) investigation should be identified. operation of the facility. the structures are categorized 3. Issues that can be plans may be obtained from the owner. Historic American Building Survey (HABS) (U. Fortunately. Details of the planning for the preservation of historic structures. HABS publishes an index of all drawings that are stored in . photographs.S. descriptions of elements. requirements and applicable code requirements. the fabricators. no documentation is structures. and test data. whether temporary or long-term. sources of information that should be reviewed during the eval. Reinforced concrete designs were 3. and evaluation 3.1—Introduction often developed in a competitive commercial atmosphere. replacing.4 Strengthening requirements—Usually. there were many reinforcement systems. job field records. Department of Interior 2007) documents. and the suppliers.1R-7 2. and calculations. Newspaper clippings The conditions observed during the document review should and old photographs may be helpful during the process of be verified during the evaluation of the structure. the structure before performing the evaluation and minimizes Early textbooks and handbooks also included much of this the assumptions required to properly evaluate the structure. it is important to schedules. EVALUATION OF CONCRETE STRUCTURES BEFORE REHABILITATION 364. however. test structures should consider the current and possible future data. Archives for the architect and structural engineer. inspection. but often the strength of the system was validated by process allows the design professional to become familiar with load tests. and are especially helpful. including many reinforcing bar deformation patterns that The purpose of this chapter is to identify the documents and were protected by patents and were illustrated in catalogs. and the additional data or information the general contractor. and the results of tests included in the catalogs. and personnel (for example. 2. 3. the as-built construction. Material specifications and drawings. or by direct inspection after cover removal. the next step is to perform a field the rehabilitation or whenever foundation settlements have investigation. or fatigue. design team. and CHAPTER 4—FIELD INVESTIGATION • Location of the water table during construction. The following records may be sought: inspection reports and reports of violations. coverage of the original construction. The soils and foundation records may be information.364. and service history of the structure have been useful when foundation loadings are to be increased during collected and reviewed. including those (f) Interviews with operation and maintenance personnel. (l) Local newspapers and trade publications. reinforcing and prestressing (b) Maintenance. . overloads. included. wind. Various original construction documents may have been (i) Information on operation. and load limits. mation that may be beneficial to the rehabilitation project (j) Material test reports for all structural materials used. 4. including investigation process. 3. including: should compensate for the missing information. this information should be listed in the final report (h) Reports filed by building inspectors. repair. k) Information concerning the foundation and soil-bearing When original documents are not available. especially for deterioration. Other possible sources of information regarding recently The field investigation can be divided into the following constructed structures may be the construction superintendent three major tasks: and the owner’s representative. Mill test reports on cement. All pertinent infor- modifications and change orders. materials may be helpful. Much of the general information on early concrete systems can be found in the History of Concrete (ACI Committee 120 3. more recently constructed structures. damage. and remodeling records. Condition survey of the structure. steel. This information is valuable in the rehabilitation or departments of licenses and inspection. More information can often 1. and subsequent repairs that have occurred. Local 3. 4. methods.5—Service history 1982) and in CRSI EDR48. use in placing their products in the original construction. Copies of all documents should be made avail- (i) Drawings and specifications kept on the job. (f) As-built drawings. should be made available to the contractor selected for the and rehabilitation project. from the following: The types of information that may be available include: 1. and test results. • Soil and foundation work. bibliography. recording of accurate dimensions for structural components • Allowable pressures and foundation type used in the and presence of reinforcing steel through use of pachometers design. The files should identify the origin of the documents. (b) Results of tests on fresh and hardened concrete. Ready-mix supplier historical data on specific mixtures (d) Reports maintained by owners of adjacent structures. (c) Quality control data and field inspection reports. The state historic preservation newspaper and trade publications may also have provided office may also have drawings and reports. earthquake. (a) Records of current and former owners. files. (c) Reports from past consultant inspections. materials. All documents obtained should be organized into a set of (e) Job progress photographs. Preparation and planning. snow. Information on materials may be available. the survey capacity. including backfill and compaction conducted during construction. and team. the concrete superintendent). Verification of as-built construction.3—Materials information maintenance of the building and any distress.4—Construction information by fire. Local geotechnical engineers may be aware of verify the accuracy of previously obtained information along geotechnical and groundwater information for recently built with a condition survey to assess the physical condition of and adjacent structures. and any problems encountered during (j) Records from government or local building departments construction. Submittals delineating concrete mixture components. and the range of dates for the documents (g) Survey notes and records. The investigation includes observations to been noted. (h) Insurance reports and records of damage to the structure 3. or users of the proportions. instances of over- retained and are helpful in documenting the construction loading. occupancy. the data obtained. including able to the owner for their information. used. and (e) Weather records. and owner or developer. prepared by design professionals and material suppliers for (g) Logs of seismic activity or geologic activity.1R-8 ACI COMMITTEE REPORT the Library of Congress.6—Project documents (d) Diaries or journals kept by the construction team. (a) Correspondence between members of the construction (k) Photographs. be obtained through a personal interview with involved 2. construction records. structure. such as by • Geotechnical reports prepared before construction.1—Introduction Pile-driving records and pile cap modification drawings Once the available design. Documents that relate to the structure’s service history should be reviewed to learn as much as possible about the 3. access to the facility. and the scope of the rehabilitation project.1 Geometry and structural materials—Spans and 4. dictated required when nondestructive tests indicate an internal void by the availability of funds and time. or In particular. type. Removal and replacement of portions of a Before a detailed field observation and survey is undertaken.1R-9 The extent of each of these tasks should be based on the 5.3. procedures During the course of the field survey. To confirm the testing. Impact echo (ASTM C 1383). Variations encountered may components (for example. When original shop drawing impact of the observation and survey on the structure as well details are unavailable. Results of nondestructive tests are valid critical areas should be made during the field observations to when supplemented by a limited number of destructive test assist in planning of equipment access and inspection procedures to verify their accuracy. depend on occupancy use. change in density and moisture be due to subsequent design modifications or field changes. access equipment or permits are required. tion should be reviewed to determine the type and extent of and environmental conditions acting on a structure may be information that needs to be obtained or verified during field different from those assumed during the original design. the survey and those stated on record documents. of the structure. methodology. particularly at critical locations. use and modification of the structure. The tive testing methods can be used: imposed loads acting at the time of the field observation 1. Vehicular traffic may have to be rerouted and/or parking such as reinforcing steel size and spacing at critical sections. Code requirements for wind. complexity. A comparison can be made between loadings present during ment should be used to supplement visual observations. so the field 4. or addition of nonstructural elements or measured and recorded. it may be necessary to and appropriate forms should be developed to document determine the structure’s load history. a full description of current and To supplement field observations. content of the construction materials can affect stiffness). and for documentation reasons. structure. testing can also estimate the concrete strength and overall are required. unrecorded alterations may be the cause of deformation. a reliable estimate (ASTM E 122).3—Field verification of as-built construction capacity of the structure. observation (see 3. Exploratory removal of portions of a structure may be The scope of the field observation task is. Nondestructive inspection services. should be documented. snow. observation should also note conditions that can affect . soil pressures. structure may necessitate the installation of temporary the conclusions of any preliminary investigation should be shoring. the available documenta.2. Corrosion potential (ASTM C 876).2. information at several random locations (ACI 228.3. such as the reduced strength of the structure. recladding or changes in façade size of openings in structures and holes through components be construction. or cracking. Alteration of architectural aspects. The survey should note any changes that can affect the load-carrying 4. In addition. and 7.2R) and measurement equip. be removed for access. from because as-built conditions can vary considerably from those load transfer resulting from physical changes in structural shown on available drawings. such as rigging or underwater inspection. Ground-penetrating radar (extrapolation of ASTM D designed. and intended future use of the 6. maintenance concerns.2R. size.3. 4. Preliminary planning should also include a review of the site the results should be verified with field measurements by to establish general site conditions and determine if special removal of concrete cover at selected locations. schedule and scope of the survey. on the surface. if any finishes have to Nondestructive testing can identify existing conditions. Ultrasonic pulse velocity (ASTM C 597). or if specialized the presence of delamination. reviewed thoroughly. Various methods of available documents such as those for previous renovations. 4. both requiring the services of a subcontractor. known conditions. Both static and dynamic effects of the imposed 6432). the nondestructive testing with a meeting with owner’s representatives to discuss methods can be used to verify original construction or repair building history. Recommendations for further penetrations. and the expectations of the owner. Carino and Malhotra 2004). 4.2—Preparation and planning If the original construction reinforcing details or original Planning for the preliminary investigation usually begins shop drawings are available. and seismic loads may have increased since the structure was 3. Reinforcing steel cover meter (pachometer). if services of subcontractors are required such as the potential for embedded reinforcing steel corrosion. Sounding or chain drag (ASTM D 4580).3. Penetration resistance (ASTM C 803/C 803M and C 805). proposed uses should be obtained from the owner. in part. can also affect the dead loads. spaces may have to be cordoned off temporarily in garage An adequate number of tests at selected locations establishes structures to accommodate survey and testing operations.2 Imposed loads—Because the imposed loads understand any changes to the original design of the structure. In planning these tasks. EVALUATION OF CONCRETE STRUCTURES BEFORE REHABILITATION 364. photography or video-recording of concrete quality.2 Loadings and environment—The loads.6). the following nondestruc. Additionally. 2. relying upon any information obtained in the field. loads should be considered in the evaluation. It is essential that location and addition of partition walls. nondestructive testing methods may as the users of the facility.1 Dead loads—Differences between design and cross sections of the structural components and elements actual dead loads may arise from variations in the dimensions should be measured. nondestructive testing (ACI 228. have to be used extensively to establish existing conditions. but should be sufficient or region of honeycombing that may not be visibly evident to include relevant information consistent with project goals. to provide the appropriate means of access. investigation and subsequent repair may be required to fully 4. age. and separations of structural elements and be plotted and a determination of whether the crack is cracks that result from differential settlements should be actively moving or dormant should be made. 4. Equipment and machinery operating loads. in the vicinity. If signs of differential settlement elements or cladding. types of soils. and is acceptable in one circumstance may not be acceptable in another. 224. a slope exceeding L/50 (1/4 in. For recorded using the guidelines in ACI 201. as well as avoiding unnecessary effort to locate Sketches. Photographs and videos can be valuable orated areas with respect to the entire structure being in this regard. whether structural or nonstructural). as would a (a) Measure and record crack width. distress or corrosion of embedded reinforcing steel. including effects of drifting. surveyed should be noted. The shear. videos. corroded. The survey records should be supplemented with location and size should be measured and recorded.5—Unsafe or potentially hazardous conditions distress. and videos. photographs. without prejudging the cause and type of any deterioration identified. investigation. Moreover./ft) would be noticeable. the owner should be immediately notified of . Continuous observed conditions. or ties to architectural storm sewers. (f) Signs of foundation settlement or heave and related 4. and 224. Before commencing the field ACI 224R. and the addition (d) Loose. the existing foundation (b) Surface defects such as spalling or delamination due to design drawings should be reviewed for type of foundations. such as leakage and areas of poor hazardous are discovered at any point during the field drainage or ponding. Therefore. it may be necessary to carry out a more detailed (e) Permanent or transient deformations.4. Impulse/impact loads (for example. 32.2R for further information. For horizontal components. should include a survey of any foundation settlements. and adjacent structures. but rather. or unspalled regions. durability. The extent and severity of deteri- evaluated objectively. especially and extent of the spall and the condition of the beam in that which could adversely affect the strength. Unsafe or potentially hazardous. intended as an example of additional loadings to be considered: (i) Erosion of concrete matrix (washing out of cement and 1.1 Visible deterioration—It is generally difficult to 5. The experience of the design professional in 3. site scaling. chemical or environmental attack. service life of the structure. it is important to note the location extent and severity of any distress or deterioration. Time-related change to prestressing steel tension. Crack patterns should movements. conditions.3 Foundation settlement—The field investigation Structural cracks should be further identified as flexure. or otherwise defective connectors for of structures or other construction. drainage. lished before surveying begins for a consistent representation and understanding of the significance of the damage. quantify the visible deterioration because it depends on 6. if known. depth. and other misalignments. surrounding terrain. monitoring may be appropriate. Refer to measured and recorded. 4. out-of-plumb geotechnical investigation to fully consider the impact of the columns. length. this list is not comprehensive.4. When conditions that appear to be unsafe or potentially (g) Water problems. fine aggregate). measurements.2 Visible deviations and deformations—Visible portions of the structure should also be included in the deviations of components or elements from the intended survey. and or adjacent structures or components or elements thereof. 1989. 2001): represents the span length. Previously repaired or modified 4. Survey 4. effects of traveling subjective criteria and experience. including the extent and The field investigation should note any changes in the amount of reduced cross section.4—Condition survey and visual inspection descriptions such as the following may be used: ACI 201.364. Thermal loads and differential thermal effect. (c) Corrosion of reinforcement. tilts. 4. are present. Therefore. design water table. gate reaction or scaling. if spalling of a The condition survey should document the approximate concrete beam is recorded. and 54 (Concrete approximately L/240 are likely to be noticed where L Society 1992. the survey descriptions should supplement the condition survey using should describe the conditions adequately so they can be the preceding descriptions. A partial list of imposed loads is offered for (h) Evidence of physical or chemical deterioration due to consideration. or direct tension. of the concrete. Acceptable or good condition. deflection-length ratio of more than approximately L/240. 22. assessing a broad range of concrete distress/deterioration 4. (j) Other concrete material problems.1R and the Concrete example.1R-10 ACI COMMITTEE REPORT dynamic response. Appraisals appropriate sketches. measured. such as. honeycombing. location. Seismic loads. and 2. deterioration that cranes). Snow and ice loads. such as underground precast concrete elements. and brief deterioration that may not be present. photographs.1R should be followed in surveying the condition 1.1R. investigation of foundation settlement. alkali-aggre- 3. Minor distress or deterioration. deviations from the vertical or horizontal in excess of Society technical standards No. The condition of a structure should be surveyed 2. Conditions of deviations are often guided by comparisons with neighboring listed as follows should be identified.4. Severe distress or deterioration. Moderate distress or deterioration. Warehouse and storage loads. guideline descriptions should be estab- 7. and type (that is. any signs of erosion and scour. or minimizes the potential for missing or misdiagnosing 5. For example. and efflorescence. water table. 1R. For example.1R. concrete property. 5. may allow analysis to confirm suitability for limitations (Thornton and Alexander 1987.1). ACI 228. 5. properties of interest are presented observed to be in sound condition and without defects. or and no change of usage is planned. There may be no need for the acceptability of the embedded steel reinforcement.2—Determination of testing requirements 5. exhibiting a wide range of distress or deterioration over . elastic ments indicate the average wave speed through the entire modulus. In the first case. its elements. load testing). EVALUATION OF CONCRETE STRUCTURES BEFORE REHABILITATION 364. These practices and (adopted from ACI 228. Variation in material properties within the structure. for example. Appropriate experience is necessary so that the concrete in the structure or to characterize some unusual or required tests are performed properly and interpreted extreme conditions in specific portions. locations will depend on: The results of the preliminary investigation should be 1. In some circumstances. as and locate flaws/defects in concrete structures (ACI 228. Variations in exposure. ASCE 11). The number and size of samples depend on the The selection of the suitable test methods (ACI 228. Carino and Malhotra 2004. whereas testing on a core sample determined in accordance with ASTM E 122 and C 42/42M measures only the condition of the material in the core. loading. safety measures may be recommended until an investigation deformation. core methods and locations where investigation into the strength samples. with each region sampled and analyzed separately. Extent of the structure over which a property is For tests intended to measure the average value of a measured. It is essential that the samples be ACI 228. Proper assessment and subsequent 5. from field tests or laboratory tests on samples removed (ACI 228.3. Alternatively.1 structure (for example. the investigator should be familiar with the test method and the accuracy and limitations of the test method. such as compressive strength.1R-11 the potential consequences of these conditions. 5.3—Testing and evaluation evacuation. Critical locations.3R. 1988.2 Evaluation procedures for steel reinforcement—The The requirements for testing will depend on the findings of properties and physical conditions of steel reinforcement. identified (labeled).4—Test methods In Tables 5. 2. a structure components are needed. Where a property is believed to be uniform. nondestructive tests. sampling locations should be distributed randomly throughout the area of interest. Otherwise. A structure that is 5. NRMCA 1999.2R) shows a summary of test methods include visual inspection. the structure. 3. ACI 437R. and record documents. advantages. number of laboratory tests to be run and the degree of ACI 228. Hookham 1994). if any. the study of available documents.2. temporary shoring measures.5—Sampling techniques deterioration or deleterious materials are suspected. Samples are usually taken to with strength test results from nondestructive testing obtain overall statistical information about the properties of methods.5. tabulated in Table 5. as the preliminary investigation. Mathey and Clifton its use without a sampling and material testing program. or air content. handled. structural materials that characterize the behavior of the 5.1R. the study area transfer points. ultrasonic-pulse-velocity measure. and use. a large structure with little or ACI 437R provides insight on the selection of test no distress or deterioration may warrant few.1 Concrete—Concrete samples can be tested to determine Tests can both evaluate the strength of existing concrete strength as well as physical and chemical properties. such as connections and lateral load- and all data treated as one group. should be considered in evaluating and the proposed rehabilitation.1 and 5.2. Temporary 5. test.1 Evaluation procedures for concrete—Table 5. CHAPTER 5—SAMPLING AND MATERIAL TESTING Concrete Society 1989). especially where design documents are available and deformation properties of a structure.2R.3. should be subdivided into regions believed to be relatively 4. discussed previously. or other emergency Evaluation of existing concrete should be based on strength. correctly.4R. uniform. ASCE 11) and the number of tests and their confidence desired. methods used to evaluate concrete properties. considered before a detailed sampling plan is prepared. ACI 214. testing where the available documentation is sufficient to complete the evaluation with confidence. and ACI 214. Guidance on developing an appropriate sampling program Strength testing of core samples will be needed to correlate is provided by ASTM C 823. Probable error in a test result.1—Introduction evaluation should provide an understanding of the structure’s This chapter contains information on practices and ability to sustain the loads and environmental conditions to procedures to investigate the condition and properties of which it is subjected (Mather 1985.2R. The selection of appropriate test methods obtained. which include field and laboratory should be used as a guide by the investigator. This table and destructive tests. Before using a procedures.2R). the number of samples should be depth of a component. the cost of testing can be so sample locations should be randomly distributed throughout high as to obviate rehabilitation as an economical solution. Requirements for testing arise where there is inadequate information about the materials in a structure or where 5. and one with test methods (primary and secondary) presented along where the dimensions measured in the field are consistent with with an explanation of their requirements. and stored properly to requires an assessment of the size and number of tests needed prevent damage or contamination (Stowe and Thornton 1984). to produce a statistically valid sample size (see Table 5. and quality properties of the structure as derived can be completed. pH Phenolphthalein (qualitative indication). UPV. compressive strength tests SASW. and aggregate Petrographic examination of concrete Assist in determination of cause(s) of distress. and location of core . properties (alkali. determine effectiveness (ASTM C 1202) of chemical sealers. split tensile strength impulse-response useful in determining the tensile strength tests (ASTM C 496/C 496M) capacity of concrete Acid-soluble (ASTM C 1152/C 1152M) Chloride ingress increases susceptibility of Chloride-ion content and water-soluble (ASTM C 1218/C 1218M) Specific ion probe (SHRP S-328) steel reinforcement to corrosion SHRP surface airflow method (SHRP S-329). these situations. and bleeding. and deep beams because concrete properties will vary with elevation decrease in the risk that the error is exceeded. (15 mm). cracking in concrete.364. (ASTM C 856 and C 457). as well as void geometry infrared thermography. Measures in-place permeability index of the near- Air permeability Figg Technique surface concrete 0. size. (ASTM C 856). delaminations impulse response impact-echo. walls. UPV. drilled in pullout test not standardized by ASTM Relative compressive Rebound number (ASTM C 805). Similarly. pullout testing (drilled in) strength in different locations.60 in.2R and ASCE 11) Possible test methods Property Primary Secondary Comment Cores for compression testing (ASTM C Penetration resistance (ASTM C 803/ Strength of in-place concrete. samples removed from structure — degree of damage. UPV gives average result through the thickness Tensile strength Splitting tensile strength of cores — Determine approximate tensile strength of (ASTM C 496/C 496M) concrete Flexural strength Break-off test (Carino and Malhotra 2004) Sampling and testing of sawed beams Limitations posed by aggregate size and (ASTM C 42/C 42M) nonhomogeneity Density Specific gravity of samples — Special technique requiring calibration curve (ASTM C 642) Moisture content Moisture meters (ASTM D 3017) — — Static modulus of Compression test of cores (ASTM C 469) — — elasticity Dynamic modulus of Resonant frequency testing of sawed Ultrasonic pulse velocity (ASTM C 597). increasing the sample size results in only a minimal components or elements. compressive strength tests SASW.1 Core sampling—The procedures for properly sampling and testing can occur through use of lower-bound removing concrete samples by core drilling are given in default material properties (FEMA 356-357). and overlays Air content. Rebound number influenced by near-surface strength sonic pulse velocity (UPV) (ASTM C 597) — properties. quality of concrete when silica reactivity. additional sampling and testing would not be justified under segregation. results vary depending on the moisture content of concrete AC resistance useful for evaluating Electrical resistance AC resistance using effectiveness of admixtures and cementitious SHRP surface resistance test (SHRP S-327) additions. such as columns. reduction or elimination of the 5. of concrete four-probe resistance meter SHRP method useful for evaluating effectiveness of sealers Internal voids.1. split tensile strength is thawing damage (ASTM C 39/C 39M). The cost of due to differences in placing and compaction procedures. Requires knowledge of density and Poisson’s elasticity specimens (ASTM C 215) impact-echo. cement content. UPV. impact-echo. radar different parts of the structure may warrant numerous Concrete is not an isotropic material and properties will samples to adequately diagnose the conditions. In some Particular attention should be given to vertical concrete cases. originally cast and current freezing-and-thawing cement content (ASTM C 1084) susceptibility) Alkali-silica Petrographic examination of concrete Establish in field if observed deterioration is reactivity (ASR) samples removed from structure Cornell/SHRP rapid test (SHRP C-315) due to ASR (ASTM C 856 and C 457) Assess corrosion protection value of concrete Carbonation.1—Test methods to evaluate hardened concrete in existing structures (adopted from ACI 228. membranes. comparison of Compressive strength 42/C 42M and C 39/C 39M. split tensile strength impulse-response of damaged surface tests (ASTM C 496/C 496M) Petrographic examination of cores Freezing and thawing can cause internal Freezing-and. Acoustic impact (ASTM D 4580). ASTM C 42/C 42M. depth of carbonation Petrographic examination of cores Fire damage (ASTM C 856).3R) C 803M). also be considered in the selection of sample sizes. impact echo. dynamic modulus waves (SASW) is typically greater than static elastic modulus Shrinkage/ Length change of drilled or sawed expansion specimens (ASTM C 341/C 341M) — Measure of incremental potential length change Resistance to Electrical indication of concrete’s ability Establish relative susceptibility of concrete to chloride penetration 90-day ponding test (AASHTO T 259) to resist chloride-ion penetration chloride-ion intrusion.1R-12 ACI COMMITTEE REPORT Table 5. pH indicators with depth and susceptibility of steel reinforce- pH meter (for example.5. ACI 214. spectral analysis of surface ratio (except ASTM C 215). Gamma radiography and personnel. ultra. Petrographic examination. equipment. litmus paper) ment to corrosion. The number. Success dependant on test procedure. Rebound number permits demarcation (ASTM C 39/C 39M). Cost should vary depending on the direction that samples are taken. For longer spans or larger areas. but is testing should be undertaken with extreme care. 5. Newer nonprestressed reinforcing steel typically accordance with the applicable ASTM standard. rate (SHRP S-324 and S-330) influenced by environmental conditions Tensile testing Tension testing of metallic materials — Tension testing of removed samples (ASTM A 370 and E 8) Chemical analysis Lab test on sample (ASTM A 751) — Needed for determining weldability or to confirm bar grade Protective coating Remaining coating thickness on exposed — Requires calibrated test equipment thickness surfaces (ASTM E 376. Coupons for testing may beam samples. more specimens should strength value should be taken as the average of the three be taken from locations well distributed through the portion cores.1. (100 mm) in length. 5. Also. it is recommended that 3. tendons are accessible. verify reduction (requires direct contact with steel) location and extent of deterioration. exhibits low variability in material properties across a structure. The minimum gauge length for testing mechanical in-place strength and that recorded by tests on retrieved properties should be in accordance with ASTM A 370. samples may be encountered when using cores and sawed Shorter samples may still be useful. was used. Sampling and testing of related to nonprestressed reinforcement are: prestressed reinforcement should be done by experienced 1. strength test. using frequently used when evaluating chemical or physical proven safety procedures. less sampling may be needed to gain reasonable appropriate. slippage of the center wire in a stress in the reinforcement. square. selection.5. is feasible on one core. at least three cores reinforcement (not stirrups or ties) (ACI 437R). for variations in core test strengths. Not more than one specimen seven-wire strand can influence measured properties. recommended unless the presence of corrosion. observe cross-sectional area diameter. location pachometer. EVALUATION OF CONCRETE STRUCTURES BEFORE REHABILITATION 364. the diameter of the core should be in 6. jaws. and preparation of samples are loss of prestress is identified. provide more certainty in structural capacity calculations Corrosion potentials Half-cell potential (ASTM C 876) — Identification of active reinforcement corrosion Corrosion rate Linear polarization Electrochemical impedance Corrosion rate of embedded steel. ground-penetrating radar X-ray and γ-ray radiography Steel location and distribution.2R and ASCE 11) Possible test method Property/condition Primary Secondary Comment Reinforcement Expose reinforcement for measurement. Information from grade marks and mill marks from reinforcing bars should be collected when possible and used For determining compressive strength or static or dynamic as appropriate in guiding sample collection.5. Sampling of broken concrete generally should not be used Sampling of prestressed reinforcement for laboratory where a strength property of concrete is in question. G 14. Even though more than one test. or iron-based reinforcement core sampling. 5. G 20) Note: Other mechanical property testing of metal components. where smooth. the visual examination and lift-off tests can be conducted to measure the prestress force. should be removed from the same cross section of a structural special end chucks may be required to prevent slippage in the component or element.2—Test methods to determine structural properties and determine condition of reinforcing steel (partially adopted from ACI 228. ultrasonic thickness gauge Intrusive probing. Refer to ACI 214. The 4. G 12. Some general considerations generally locks up in bond. at least will be no influence from previous tests. For structural elements having a span of less than 25 ft separate core samples be used for different tests so that there (7.5 m) or a loaded area of less than 625 ft2 (60 m2). cracking. or The characteristics. radiography corrosion of embedded post-tensioning components. For older ASTM C 42/C 42M may be used as an alternative to drilled structures. A single core should not be used to evaluate or diagnose being investigated to determine whether or not the same a particular strength problem (ACI 318).4R strength of steel was used throughout the structure.4R and ASCE 11).3 Random sampling of broken concrete— which will provide some information on physical properties. The strand should not be allowed to rotate during testing. Bonded prestressed reinforcement discussed in ASTM A 370. should be removed at each location in the structure. additional sampling may be needed. For example. 5. . and however.2 Sampling of concrete with sawed beams—Where As a result.1. Specimen locations should be separated by at least the laboratory tests. sampling by sawing beams in accordance with confidence in in-place mechanical properties.2 Steel reinforcement—Samples of steel reinforcement Sampling of bonded tendons and wires is generally not can be tested to determine its physical or chemical properties. such as hardness and impact. concrete cover (GPR) (ASTM D 4748) Reinforcement Expose reinforcement and measure Observe and measure rust and reduction in steel. such as development length of the reinforcement to avoid excessive nondestructive pulse velocity testing followed by compressive weakening of the component. Research (including ACI 214.5. samples should be carefully selected to permit all necessary 2. modulus of elasticity. Specimens should be removed at locations of minimum personnel.1R-13 Table 5. be obtained from samples even 4 in. are described in ASTM A 370 and E 8 and their references. Where cores are one specimen should be taken from the main longitudinal taken to determine a strength property. When the anchorages of unbonded deterioration by petrographic or other laboratory analyses. has shown that significant variations between 7. Various design standards (for example. testing of full. and compatibility with existing Sometimes it may be impractical to conduct a full-scale materials (ACI 546R). Rehabilitation of historic structures often requires repair Another reason for a load test is uncertainty of behavior due concrete mixtures to match the color and texture of the to deterioration or complexity of the system. ACI 318) with attention given to the rehabilitation alternatives should be identified along with fact that the calculation is for an existing structure. used to determine the strength and ductility of critical Common concrete protection measures include sealers. The capacities of the critical structural scope thresholds beyond which the structure needs to be components should be determined by an appropriate method upgraded. might not techniques should be based on the exposure conditions for be valid if the behavior of the structure beyond the elastic both installation and service. (889 mm) sample lengths should condition. installation constraints.1—Introduction identified for evaluation. and loads to which the structure has been and Many building codes contain change-in-use and rehabilitation will be subjected. The tolerance of structural components and strengthening methods and techniques should be determined. the most common method. deterioration introduces significant uncertainties about the parameters required to perform a meaningful analysis using generally accepted engineering principles. The initial and long. The reasons for. is the strength of all critical elements of the structure and the recommended when sufficient information is available about structure as a whole. Variability their advantages and disadvantages. of the available design and construction documents. the and the amount of information known about its existing type and physical condition of the structure. The effect of nonstructural survey. elements to deterioration and distress is highly variable and Architectural and historic requirements. appropriate (ACI 437R). Evaluation by full-scale load testing is recommended 6. by analysis and structural modeling. analyze the structural behavior of the components. The ability of the structure to meet the physical characteristics. should be evaluated (Brown 1992). Where code requirements are not met. portions of the structure. This investigative process of components on the overall performance of the structure evaluation cannot be standardized into a series of well. The architectural layout methods unreliable. or when the 6. when the nature of existing distress and should be evaluated for use. elements being evaluated cannot be readily determined. and connections should be 6.or reduced-scale models can be for future repair may be desirable in certain situations. should also be considered. such as changes situation-specific (Hookham 1994). . Dead and live loads. Structural evaluations should be performed to determine Evaluation by analysis. structural current code loading requirements should be considered. configuration. in materials. The final selection of materials and using full-scale load-testing procedures. load test of the component under consideration. equipment and Evaluation is a process to determine the adequacy of a piping loads. the completeness condition. material properties. minimum gauge length for the sample is 24 in. condition prescribed loads and deformations. and the evaluation by analysis and physical load testing. structural limit cannot be reliably predicted. dimension and geometry measurements. the strength of the structure or portion of the structure being evaluated should be determined.1R-14 ACI COMMITTEE REPORT Testing of samples for mechanical properties is addressed in 6. so at least 35 in. In such protection measures to reduce further deterioration and need situations. components. material evaluations. It may and implications of. The choice of the evaluation defined steps because the number and type of steps will vary method (ACI 437R) is dependent on the nature of the structure depending on the specific purpose of the investigation. and be recovered. or evaluation strength and quality of the existing construction materials. Evaluation existing concrete. Analysis of components in architectural layout or modifications to the façades of the and elements should be based on proven principles and structure. In addition to the repair or replacement. nonstructural components should also be analyzing the information and data assembled from reviews evaluated to determine if they are capable of resisting the of existing documentation. should be considered. It is generally necessary to model coatings. and needed space. term costs of alternatives should be estimated. structure or component for its intended use by systematically Where applicable. Using the information obtained from the field survey of (610 mm). however.2—Dimensions and geometry when an insufficient amount of information is available to The actual dimensions of the structural components should be determined for use in evaluation.3—Materials evaluation Candidate materials and techniques for strengthening geometry and the material characteristics of the structural repair or replacement should be identified and evaluated. accounted for in strength-reduction factors. The typical choices are evaluation by analysis.4—Structural evaluation ASTM A 370. architectural requirements. such as in the case of a performance requirements. the behavior of the structure to get reliable results. and cathodic protection (impressed current and all of the structural features that significantly contribute to sacrificial anodes). field inspection. and material testing. service-life requirements. CHAPTER 6—EVALUATION Critical elements. access.364. and wind requirements should be considered. severely deteriorated structure. discrepancies between the field-measured also be necessary to conduct a full-scale load test when the dimensions of the critical structural components and those complexity of the design concept and lack of experience with indicated on available drawings should be understood and the structural system make evaluation solely by analytical properly considered in the evaluation. results of as-built verification efforts including all deviations. 1. and intent regarding funds available and the long-term plans for other costs such as falsework/rigging. construction likely be influenced by first-hand knowledge of the client’s administration. documentation review should be summarized and supple- tenance and repair history. ongoing safety) to complete demolition and replacement. both initial and long-term. and identify their advantages not available. drawings. foundations. acceptable rehabilitation alternatives. The prediction of the structure’s service life. size. present and future. reflects the time value of money. The life. and unknowns regarding future A cost evaluation of each repair. in the influences of adjoining structures should be included.6—Evaluation of rehabilitation alternatives With any rehabilitation project. predicted from the maintenance and repair records of the owner and from contractors who specialize in concrete repair 7. strengthening. and architectural and structural case histories and data from similar projects. reinforcing steel layout) made throughout the structure. and replacement alternative should be prepared. Findings and recommendations. This report generally during the selected evaluation period. there are usually several 7. The results of the inspection and condition survey for the ening. 5. Degree of disruption to ongoing operations. the costs of engineering and other technical services. the facility. The results of the and chemistry expertise. including any modifications made during the course of the Analyses can be performed for a range of rates to evaluate evaluation. It should include 5. and other pertinent information prepared during the inspection 3. including location.5—Cost evaluation 4. LCC is expressed in equivalent 2. . Between these extremes are usually several rehabilitation major deficiencies. history. and The costs for future maintenance and repair can often be 6. EVALUATION OF CONCRETE STRUCTURES BEFORE REHABILITATION 364.1R-15 6. is monitored to ensure report should briefly describe methods and equipment used. Sampling and material testing results. legal costs. Purpose and scope of investigation. copies of drawings. The case of a deteriorating structure. and the salvage value at 1. A summary of information on the existing structure life prediction requires engineering judgment. the rehabilitation alternatives or loss of income. service life) along with valid escalation and discount rates. Clients should provide input on the desired This section of the report should describe the purpose and repaired life of the structure (which may be different than scope of the investigation as agreed upon with the owner. Documentation recovered to support evaluation. including its façade. The design professional’s final recommendations will construction materials. refer to ACI 365. Alternatives can range structure. and deterioration or distress that require alternatives. Salvage value. the various as preliminary or detailed. 6. materials science details should be included in this section. evaluation provides a rational basis upon which a selection For projects with rehabilitation alternatives that have can be made. Costs will include includes a brief description of the following basic areas those listed in the preceding paragraph as well as estimated addressed during the evaluation process: future maintenance and repair costs. remedial work. construction management if appropriate. estimated inflation rate and a selected discount rate that 4. and all portions of the structure that are to be The design professional should propose technically rehabilitated or altered for change of use or appearance. and the extent and frequency of future repair and protection work is crucial to a 7. Risks. meaningful service. terms (often present value) by adjusting future costs with an 3. should be clearly stated. repair and protection alternatives.1—Introduction cycle cost (LCC) method is a commonly used procedure. labor and equipment. with the guidance of the design professional. the following: assumptions on dimensions and configuration (for example. sketches. Magnitude of costs. Evaluation process and results. uncertainties. the report should describe methods used to size and disadvantages. or replacement. and input from the client on main. and from doing nothing (as long as the structure is safe and. The 2. The results of the entire investigation and evaluation LCC is the sum of all costs. and applicable building upper. but are not necessarily limited to. significant assumptions. or performance and future maintenance and repair needs. codes and standards.and lower-bound LCC values. A list of all the documents reviewed or referenced and their sources should be included. achieved. experience.3—Documentation recovered to support meaningful LLC analysis. pertinent information as applicable. Advantages and disadvantages may and quantify structural components. For more detail on economic mented by photographs. such as the rehabilitation of a deteriorating structure. rehabilitation alternatives should CHAPTER 7—FINAL REPORT be evaluated using economic evaluation methods. soils. traffic control.2—Purpose and scope of investigation and protection. Field observations and condition survey results. 7. evaluate their costs When drawing documentation (such as design or as-built) is (both initial and long-term). the end of the evaluation period.4—Field observations and condition survey alternatives for accomplishing the necessary repair. strength. that occur should be summarized in a final report. and any other evaluation and service life models. differing and significant future costs.1R. Available service-life prediction evaluation models are in their infancy. this should include such include. and field survey operations. The level of investigation undertaken. In any event. and protection. Degree to which the rehabilitation objectives are report should also include photographs. Consequently. the effects on ongoing operations. users. The evaluation results should also identify determined by the urgency of the rehabilitation needs. future performance of all structural and architectural materials 7. Recommendations to improve building performance for and mobilization. Project planning meetings are identify an appropriate course of action for the structure or often helpful in determining the most appropriate way of components of the structure. and results of the nondestructive Effective plans should address what action should be taken and destructive testing performed during the detailed and how it should best be accomplished. The around existing operations and structure use. or provide suitable protection against failure such The standards and reports listed below were the latest as shoring. Additional testing or analysis that could be used to the optimal construction conditions. along with sketches the life expectancy of various systems and alternate rehabil- or drawings showing typical details.7.364. or in this section of the report. 6. If required.1—Referenced standards and reports 5. alternate or strengthening method studied.1 Action plan—The recommendation should clearly should also be considered. rehabilitation procedures for 7. should be included. It is of critical importance to 1. the any follow-up recommendations for the structure. and permitting. or involve hazardous constraints and feasibility. methods.6—Evaluation exert a major influence. and the life expectancy and life-cycle costs impact of the rehabilitation method on the structure and its of the entire structure. If rehabilitation work is confirm report conclusions. The report should also clearly indicate the extent to which strengthening or rehabilitation is The total cost estimate should also include cost of the necessitated by code-mandated provisions along with any engineering services. Conduct additional testing or evaluation. mance concerns) identified.7. materials. testing services. while not necessarily controlling the final recommendations. Any immediate remedial actions needed from a safety suitable or temporary protection measures may have to be or serviceability perspective. and an appropriate and cost.7. and 1. Long-range maintenance suggestions to reduce the engineering. it may be practical to assign priorities to supplemented with photographs and copies of laboratory test rehabilitation and to stage the program accordingly over reports as appropriate. and of action should be identified. discussion of the current condition and expected future 7. Feasible alternatives to the recommended plan of the structure in terms of physical condition. such as: availability of funds. noise. Phase out of service.7. considered.7—Findings and recommendations are found during rehabilitation. or editions available at the time this document was prepared. 8. work may be delayed until the weather is 2. . The results should indicate adequacy several years. association if it is desired to refer to the latest version. usually 7. Where unknown conditions exist. The results may be constraints exist. aspect of a recommended rehabilitation plan and. Special consid- recommendations should address the following topics: erations are warranted for construction operations that action plan. a brief description of each rehabilitation impact of a deferment on a rehabilitation program. Close. CHAPTER 8—REFERENCES 4. sufficient seismic events. required outdoors. Because these standards and references are revised frequently. distress. Site access and materials-handling problems 7. and the itation schemes. should be presented (ACI 365. Adequate delivery time for The findings from each preceding task should be summarized special materials. and contingencies. special conditions (for example. considered and incorporated into the rehabilitation plan. and their rates should both be taken into account when evaluating the results. scheduling. including estimated costs. and the feasibility of the tion often involves the constraints associated with working rehabilitation under various scenarios and options. cost estimates.3 Scheduling—The project schedule is usually historic buildings). and determining produce dust.1R). and Sufficient time should be allowed for contractor selection 4. Where budget investigation should be summarized. Change the use. Inflation rates and interest based analyses that were prepared and executed.1R-16 ACI COMMITTEE REPORT 7. Correct deficiencies (deterioration. Additionally. cost estimates. ensure that any constraints mandated by the owner be 2.5—Sampling and material testing results effective solution for the rehabilitation should be developed. 3. preparing construction documents. odor. Cost estimates should address the The report should summarize the results of the strength owner’s requirements and consider the effects of interruptions and deformation evaluation of the structure and components of normal operations. The schedule should consider the lead time for 3. the influence that deferring of a particular phase would have including the structural model created and any computer- on future rehabilitation costs.4 Constraints and feasibility determination—Rehabilita- performance of the structure.2 Cost estimates—Project costs often influence every and components tested. Accept as is. such as: handling these constraints. possibility for deterioration. All assumptions made and methods possible phasing (or staging) of the project and to identify used in the evaluation process should be clearly documented. Finally. new or replacement equipment. it is helpful to study and elements thereof. The findings should include a prefabricated components should be considered. vibrations. or perfor. The course of action that will best satisfy the owner’s the reader is advised to contact the proper sponsoring group or objectives should be considered. time should be allowed for possible modifications and additional engineering services if newly discovered deficiencies 7. strength. The locations. and Terminology Investigation for Chemical Analysis of Steel Products E8 Test Methods for Tension Testing of C39/C 39M Test Method for Compressive Strength of Metallic Materials Cylindrical Concrete Specimens E 122 Practice for Calculating Sample Size to C 42/C 42M Test Method for Obtaining and Testing Estimate. with a Specified Tolerable Error.4R Guide for Obtaining Cores and Interpreting C 1084 Test Method for Portland-Cement Content Compressive Strength Results of Hardened Hydraulic-Cement Concrete 224R Control of Cracking in Concrete Structures C1152/C 1152M Test Method for Acid-Soluble Chloride in 224. or Sawed Specimens of Hydraulic- G 12-83(1998) Test Method for Nondestructive Measure- Cement Mortar and Concrete ment of Film Thickness of Pipeline Coatings C 457 Test Method for Microscopical Determi- on Steel nation of Parameters of the Air-Void System in Hardened Concrete G 14 Test Method for Impact Resistance of C 469 Test Method for Static Modulus of Elasticity Pipeline Coatings (Falling Weight Test) and Poisson’s Ratio of Concrete in G 20 Test Method for Chemical Resistance of Compression Pipeline Coatings C 496/C 496M Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens Concrete Reinforcing Steel Institute (CRSI) C 597 Test Method for Pulse Velocity through EDR48 Engineering Data Report.1R Service-Life Prediction Plates Using the Impact-Echo Method 437R Strength Evaluation of Existing Concrete Buildings D 3017 Test Method for Water Content of Soil 546R Concrete Repair Guide and Rock in Place by Nuclear Methods (Shallow Depth) American Society of Civil Engineers (ASCE) D 4580 Practice for Measuring Delaminations in ASCE 11 Guideline for Structural Condition Assessment of Concrete Bridge Decks by Sounding Existing Buildings D 4748 Test Method for Determining the Thick- ness of Bound Pavement Layers Using ASTM International Short Pulse Radar A 370 Test Methods and Definitions for D 6432 Guide for Using the Surface Ground Mechanical Testing of Steel Products Penetrating Radar Method for Subsurface A 751 Test Methods. Process Longitudinal. Evaluation and Repair of Cracks in Mortar and Concrete Concrete Structures C 1202 Test Method for Electrical Indication of 224. and Torsional Frequencies E 376 Practice for Measuring Coating Thickness of Concrete Specimens by Magnetic-Field or Eddy-Current (Elec- C 341/C 341M Practice for Length Change of Cast.1R Guide for Making a Condition Survey of Concrete Hardened Concrete in Constructions in Service C 856 Practice for Petrographic Examination of 207.1R Causes.3R Practices for Evaluation of Concrete in Existing Hardened Concrete Massive Structures for Service Conditions C 876 Test Method for Half-Cell Potentials of 214. Drilled Cores and Sawed Beams of Concrete the Average for Characteristic of a Lot or C 215 Test Method for Fundamental Transverse. EVALUATION OF CONCRETE STRUCTURES BEFORE REHABILITATION 364. tromagnetic) Examination Methods Drilled. Practices.1R-17 American Association of State Highway and Transportation C 642 Test Method for Density.3R Simplified Version of the Recommended Practice Uncoated Reinforcing Steel in Concrete for Evaluation of Strength Test Results of Concrete 214.1R In-Place Methods to Estimate Concrete Strength Penetration 228. Absorption. Evaluation of Concrete Reinforcing Bars in Old Structures .2R Nondestructive Test Methods for Evaluation of C 1218/C 1218M Test Method for Water-Soluble Chloride Concrete in Structures in Mortar and Concrete 318 Building Code Requirements for Structural C 1383 Test Method for Measuring the P-Wave Concrete and Commentary Speed and the Thickness of Concrete 365. and Officials (AASHTO) Voids in Hardened Concrete T 259 Method of Test for Resistance of Concrete to C 803/C 803M Test Method for Penetration Resistance of Chloride Ion Penetration Hardened Concrete C 805 Test Method for Rebound Number of American Concrete Institute (ACI) Hardened Concrete 116R Cement and Concrete Technology C 823 Practice for Examination and Sampling of 201.2R Cracking of Concrete Members in Direct Tension Concrete’s Ability to Resist Chloride Ion 228. Washington. 122 pp.. Reston. National Academy of Sciences) 8. C.usace. Army Corps of Engineers.” Proceedings. NRMCA.cr. 1984. 1987. Mich. 2001. M..org Stowe. 1992. 22. Surrey. and Thornton. Vicksburg. M.S. www. R. 54. 32. J. Washington DC 20472 Thornton. “Damage Tolerance Analysis in www. The preceding references are available from: Concrete Society. G. London WCIV 614B). J. and Malhotra. 49 High S-329 Condition Evaluation of Concrete Bridges Relative Holborn. Preser- for Evaluating Effectiveness of Penetrating Sealers vation Assistance Division. ASTM International Mather.” U. “Engineering Condition Survey of Concrete in Service.astm. Farmington Hills MI 48333-9094 Hookham. Md. Jr.1R-18 ACI COMMITTEE REPORT Federal Emergency Management Agency (FEMA) U. Department of the to Reinforcement Corrosion.C. H..gov “Development of Nondestructive Testing Systems for In Situ Evaluation of Concrete Structures.364. Army Corps of Engineers. 1988.C. Handbook on for Field Measurement of Concrete Permeability Nondestructive Testing of Concrete. Surrey. UK. Washington DC 20418 “Historic American Building Survey (HABS). T.” for Field Determination of Total Chloride Content (Available from Her Majesty’s Stationery Office. Va. Army Corps of Engineers 356-357 Prestandard and Commentary for the Seismic Waterways Experiment Station Rehabilitation of Buildings Vicksburg MS 39180-6199 www. American Concrete Institute Concrete Society. UK.. Volume 2: Method Brown.” Technical Report Federal Emergency Management Agency REMR-CS-1.fema. National Schaumberg IL 60173 Ready Mixed Concrete Association. ACI Reactivity in Highway Structures Bibliography No.htm D.. Volume 7: Method Carino.2—Cited references C-315 Handbook for the Identification of Alkali-Silica ACI Committee 120.. Concrete Aggregates Concrete Society.org Structural Rehabilitation. 1970.” Technical Report No.” NBS Technical Note 1247. V. Department of Interior. “Photographing Historic Buildings to Reinforcement Corrosion. UK. 1994. K. “Recording Historic Buildings. Farm- S-324 Condition Evaluation of Concrete Bridges Relative ington Hills. West Conshohocken PA 19428 Oct. 110 pp.org Mathey.” Concrete International. 7. and Clifton.. 1999. “Review of Nondestructive Evaluation Methods Applicable to Construc- American Society of Civil Engineers tion Materials and Structures..S. 1801 Alexander Bell Dr U.. National Park Service. 2nd Edition.tfhrc. N. Waterways National Academy of Sciences Experiment Station. L. “Preservation Technology: Evaluating 100 Barr Harbor Dr Concrete in Structures.mil/ Strategic Highway Research Program (SHRP) (Transporta- tion Research Board. National Park Service. American Concrete Institute.crsi. www. to Reinforcement Corrosion. 2004. Surrey. A. 1983. T.. H.S. http://www.. T. “The Secretary of the Interior’s for Measuring Corrosion Rate of Reinforcing Steel Standards for Rehabilitation & Illustrated Guidelines for S-327 Condition Evaluation of Concrete Bridges Relative Rehabilitating Historic Buildings. R.S. Cultural Resources. 10. Auerbach S-330 A Guide to Determining Optimal Gradation of Publishing. H. and Alexander.. ASCE Structures Congress. U. D. History of Concrete. Volume 6: Method (London: Royal Commission on Historical Monuments).army.” Washington. Silver Spring. pp.gov/habshaer/habs/ . No. 1992.. “Analysis of Hardened Concrete. www. Volume 52: Method Interior. Waterways 500 C Street SW Experiment Station. R. 14.” Committee on Research Engi- 933 North Plum Grove Rd neering and Standards. 1982. “Nonstructural Cracks in Concrete. Publication No. Miss. 392 pp.” Technical Report No.. Department of Commerce. 33-41. www.” Technical Report Strategic Highway Research Program (SHRP) REMR-CS-10..” Technical Report No. 2101 Constitution Ave NW U.S..org Historic American Buildings Survey. 2007.gov/pubrds/marapr98/shrp... Reston VA 20191-4400 McKee. U. S-328 Condition Evaluation of Concrete Bridges Relative Buchanan. V. Washington. Miss.concrete.nps.C. 1985. “Diagnosis of Deterioration of PO Box 9094 Concrete Structures. to Reinforcement Corrosion. W. Vicksburg. D. 1989. “In-Place Concrete Strength Evaluation—A Concrete Reinforcing Steel Institute Recommended Practice. 133-99.” www.asce.S. including documents. its original chartered purpose remains “to provide a comradeship in finding the best ways to do concrete work of all kinds and in spreading knowledge.S. · Sponsoring and co-sponsoring international conferences and symposia. you join thousands of practitioners and professionals worldwide who share a commitment to maintain the highest industry standards for concrete technology. In addition. specifications.A. Benefits of membership include a subscription to Concrete International and to an ACI Journal. ACI chapters provide opportunities for interaction of professionals and practitioners at a local level. seminars and convention registration fees.org . ® American Concrete Institute Advancing concrete knowledge As ACI begins its second century of advancing concrete knowledge. · Formal coordination with several international concrete related societies. · Educational seminars that disseminate reliable information on concrete. guides.concrete. · Spring and fall conventions to facilitate the work of its committees.” In keeping with this purpose. · Student programs such as scholarships. MI 48331 U. and competitions. · Periodicals: the ACI Structural Journal and the ACI Materials Journal. · Certification programs for personnel employed within the concrete industry. As a member of ACI. construction. Phone: 248-848-3700 Fax: 248-848-3701 www. and Concrete International. and practices. and codes. ACI members receive discounts of up to 40% on all ACI products and services. internships. American Concrete Institute 38800 Country Club Drive Farmington Hills. ACI supports the following activities: · Technical committees that produce consensus reports. For more information. www. analysis of research and development results. The committees. ACI’s membership is composed of engineers.concrete. and education. educators. There are no educational or employment requirements. as well as ACI as a whole. Guide for Evaluation of Concrete Structures before Rehabilitation The AMERICAN CONCRETE INSTITUTE was founded in 1904 as a nonprofit membership organization dedicated to public service and representing the user interest in the field of concrete. scientists. contractors. which assures all participants the right to have their views considered. Individuals interested in the activities of ACI are encouraged to become a member. construction and maintenance of concrete products and structures. ACI gathers and distributes information on the improvement of design. contact ACI. and representatives from a variety of companies and organizations. presentation of construction and repair techniques. operate under a consensus format. architects. The work of ACI is conducted by individual ACI members and through volunteer committees composed of both members and non-members.org . Committee activities include the development of building codes and specifications. Members are encouraged to participate in committee activities that relate to their specific areas of interest.