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1、ACI 362.2R-00 became effective June 2, 2000. Copyright 2000, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, o
2、r recording for sound or visual reproduc- tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors. ACI Committee Reports, Guides, Standard Practices, and Commentaries are intended for guidance in planning, designing, exe
3、cuting, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept re- sponsibility for the application of the material it contains. The American Concrete Inst
4、itute disclaims any and all re- sponsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom. Reference to this document shall not be made in con- tract documents. If items found in this document are de- sired by the Architect/Engineer to be a pa
5、rt of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer. 362.2R-1 Guide for Structural Maintenance of Parking Structures ACI 362.2R-00 (Reapproved 2005) This guide is intended to assist parking structure owners, operators, and the consul
6、tants who advise them in developing preventive maintenance programs for parking structures. It presents typical maintenance concerns and suggests ways of addressing them. The guide summarizes information regarding structural, operational, aesthetic, and routine maintenance for parking structures. De
7、sign sugges- tions to minimize maintenance are also included. A structural maintenance checklist of specific recommended tasks and references to other publica- tions with information related to the structural maintenance of parking structures is included. See ACI 362.1R for more complete information
8、 regarding design issues related to a parking structures performance. Keywords: concrete durability; condition appraisal; construction joints; contraction joints; corrosion; cracking; expansion joints; isolation joints; leakage; maintenance; membrane; parking structure; post-tensioning; pre- cast; p
9、restressed; ramp; scaling; sealant; sealer; snow removal; spalling. CONTENTS Chapter 1Introduction, p. 362.2R-2 Chapter 2Developing a maintenance program, p. 362.2R-2 2.1The project maintenance manual 2.2Periodic inspections 2.3Preventive maintenance 2.4Conditional appraisals Chapter 3Deterioration
10、problems associated with parking structures, p. 362.2R-3 3.1Concrete-related deterioration 3.1.1Scaling 3.1.2Corrosion 3.1.3Delaminations 3.1.4Spalling 3.1.5Cracking 3.1.6Leaking 3.1.7Leaching 3.2 Sealants and waterproofing 3.2.1Contraction and construction joint sealants 3.2.2Seals for isolation jo
11、ints and expansion joints 3.2.3Concrete sealers 3.2.4Elastomeric, traffic-bearing membranes 3.3Structural elements and related items 3.3.1Concrete deck surface 3.3.2Beams, columns, and walls Reported by ACI Committee 362 James C. Anderson Keith W. Jacobson*Carl A. Peterson* Ralph T. BrownNorman G. J
12、acobson, Jr.Suresh G. Pinjarkar Girdhari L. ChhabraHoward R. MayPredrag L. Popovic Anthony P. Chrest* Gerald J. McGuire H. Carl Walker* Jo CokeMartin B. MikulaSteward C. Watson Thomas J. DArcy* David C. MonroeBertold E. Weinberg Boris DragunskyThomas E. Nehil *Denotes members of subcommittee who pre
13、pared the document. Subcommittee chairman. Thomas G. Weil* Chairman Thomas J. Downs* Secretary 362.2R-2ACI COMMITTEE REPORT 3.3.3Stair and elevator towers 3.3.4Exposed metals Chapter 4General maintenance considerations, p. 362.2R-9 4.1Housekeeping and cleaning requirements 4.2Snow removal and ice co
14、ntrol 4.3Other operational maintenance 4.4Aesthetic-related maintenance 4.5Precast/prestressed concrete 4.6Post-tensioned concrete 4.7Cast-in-place, conventionally reinforced-concrete structures Chapter 5Parking facility structural maintenance tasks and frequencies, p. 362.2R-11 Chapter 6References,
15、 p. 362.2R-11 6.1Referenced standards and reports 6.2Cited references Appendix ASnow removal, p. 362.2R-12 Appendix BDeicing procedures, p. 362.2R-13 Appendix CChecklist for structural inspection of parking structures, p. 362.2R-13 CHAPTER 1INTRODUCTION All parking structures require regular mainten
16、ance to pro- vide a satisfactory level of service and meet service-life ex- pectations without premature deterioration, undue repair expense, interrupted service, inconvenience to patrons, or loss of cash flow. Parking structures can develop more dis- tress and deterioration than most types of build
17、ings because of their direct exposure to traffic, weather, deicing chemi- cals, and snowplows. Poor maintenance increases the likeli- hood of distress and deterioration and is a potential cause for damage to vehicles and personal injury. A maintenance pro- gram includes timely preventive actions to
18、reduce system failure and premature deterioration, which can reduce the need for significant and expensive repairs. This guide is in- tended for owners, operators, and consultants for parking structures who seek advice on developing and implementing a maintenance program. This guide emphasizes the m
19、aintenance of structural com- ponents to reduce risks associated with structural deteriora- tion. The types and frequency of maintenance required for a structure are directly related to the durability features incor- porated into the structure during design and construction. Deterioration problems a
20、ssociated with parking structures are discussed in Chapter 3. Operational maintenance, house- keeping, and aesthetic maintenance are discussed in Chapter 4. Chapter 5 provides a checklist for maintenance tasks and recommended frequencies. Appendices A and B contain in- formation about snowplowing an
21、d deicing procedures. Ap- pendix C also contains a worksheet for making a visual inspection. Different types of structural systems can develop different types of deterioration-related problems. ACI 362.1R contains discussion of durability considerations for parking structures. An understanding of th
22、ese issues will prove helpful in developing an appropriate maintenance pro- gram. Refer also to Sound Maintenance Extends Life Spans of Parking Facilities, by Bhuyan. CHAPTER 2DEVELOPING A MAINTENANCE PROGRAM 2.1The project maintenance manual For many projects, a maintenance manual is developed at t
23、he completion of construction as part of the close-out pro- cess. The manual can contain the project specifications; a set of as-built drawings; product information, including warran- ty and maintenance information from the manufacturers of various components; and specific maintenance require- ments
24、. If a project maintenance manual exists, it is a good idea to become familiar with the manual to develop a com- prehensive maintenance program. 2.2Periodic inspections A walk-through visual inspection should be made at least annually to provide an overview of the structures general condition. Probl
25、ems should be noted in a concise report, rec- ommending further investigation of specific items if required. The inspection should be conducted by an engineer experi- enced in structural condition assessment of parking struc- tures. A visual inspection does not involve physical testing. Maintenance
26、personnel with proper checklists and day-to-day experience of operating the structure can also conduct a visu- al inspection of nonstructural maintenance concerns. Appen- dix C provides a checklist of specific items that should be observed during a visual maintenance inspection. 2.3Preventive mainte
27、nance Preventive maintenance should reduce life-cycle repair expenses and extend the service life of the structure. This is accomplished by ensuring that the structures protective sys- tems are functioning properly to reduce the intrusion of wa- ter and deicing chemicals. Regular cleaning to remove
28、debris, wash-downs with water, sealing cracks, spot repairs of sealants and expansion joints, protective coatings and membranes, and periodic reapplication of sealers are all fea- tures of an active preventive maintenance program. 2.4Condition appraisals A condition appraisal should be performed if
29、extensive de- terioration or unexplained problems are observed during the walk-through visual inspection. The appraisal should evalu- ate and define the extent of deterioration, the associated problems observed, their causes, the causes of the problems observed, and the corrective options available.
30、 Typically, the appraisal focuses on the deterioration of deck slabs and their supporting structural elements that can reduce structural ca- pacity or cause safety hazards. Material samples can be taken and a variety of tests per- formed. The most important tests are those that determine the extent
31、of corrosion and bond loss of the reinforcement and those that quantify the amount and extent of chloride ingress into the concrete. See ACI 201.1R for additional information regarding concrete durability. Testing may include compres- sive strength, chain dragging, and half-cell testing to locate 36
32、2.2R-3GUIDE FOR STRUCTURAL MAINTENANCE OF PARKING STRUCTURES active corrosion and delamination, and chloride-ion content. In addition, petrographic analysis can be done to identify spe- cific concerns regarding the makeup of the concrete. Information gathered from the condition appraisal, along with
33、 resulting lab analyses, should be reviewed by an engi- neer experienced with structural-condition appraisals. If nec- essary, a materials consultant can confirm the causes of deterioration. These experts should provide a report with specific recommendations, including restoration priorities, option
34、s, and repair budgets. The owner should maintain accurate maintenance and in- spection records to provide historical information that can assist in future appraisals of deterioration and identify poten- tial problems observed. CHAPTER 3DETERIORATION PROBLEMS ASSOCIATED WITH PARKING STRUCTURES The im
35、plementation of a proper maintenance program re- quires an understanding of the deterioration mechanisms and their symptoms. Most deterioration involves water intrusion and corrosion of reinforcement. Problems that are left unattended during the early stages of their development can lead to safety h
36、azards for users, in- creased liability for owners, and can require expensive repair programs for correction. Structural maintenance require- ments are those actions necessary to preserve, restore, and enhance structural members and improve or enhance protec- tive functions of various waterproofing
37、and anticorrosion systems. See ACI 201.1R, 222R, and 224R for additional in- formation regarding deterioration mechanisms briefly de- scribed in this guide. 3.1Concrete-related deterioration Concrete-related deterioration is often associated with scaling, spalling, joint failure, or cracking of the
38、concrete members. Delamination of concrete, however, is not a pre- requisite for concrete-related deterioration. Sections 3.1.1 through 3.1.7 discuss various deterioration mechanisms. 3.1.1 ScalingScaling is the disintegration of cement paste at the concrete surface. Commonly associated with cy- cle
39、s of freezing and thawing, it results in progressive deteri- oration. Severe scaling can result in a loss of concrete surface integrity to depths of more than 25 mm (1 in.). Scaling in deck slabs can create depressions that pose tripping hazards and create ponding areas that can lead to further dete
40、riora- tion. See Fig. 3.1. 3.1.2 CorrosionCorrosion is an electrochemical process that results in the deterioration of reinforcement and other metals embedded in the concrete or exposed to the weather. Chloride ions from road salts or other deleterious airborne chemicals accelerate the corrosion pro
41、cess. Moisture and ox- ygen also play a direct role. Corrosion can lead to serious de- terioration and repair problems. As corrosion progresses, the corrosion byproducts occupy a greater volume than the orig- inal metal, creating internal pressure on the concrete that can eventually lead to cracking
42、, delamination, and breaking of the concrete substrate. Corrosion of unbonded post-ten- sioning tendons represent a special case. Post-tensioned tendons can corrode or even fail without cracking or delaminating the surrounding concrete. A post-ten- sioned tendon failure is often accompanied by the e
43、ruption of the tendon either at the tendon end or through the concrete slab. Other post-tensioning problems to look for include exposed tendon sheathing or dislodging of post-tensioning anchors. Mitigating the corrosion process should be a priority of any maintenance program. The most practical way
44、of con- trolling corrosion is to incorporate corrosion-protection sys- tems into the original construction and then to reduce or eliminate moisture penetration into the structure (Fig. 3.2). See ACI 222.R for a more complete discussion of the corro- sion process and its causes, and ACI 423.4R on cor
45、rosion and repair of unbonded single-strand tendons. Fig. 3.1Scaling is deterioration of concrete surfaces usu- ally caused by exposure to freeze-thaw cycles. Fig. 3.2Corrosion of reinforcement can lead to deteriora- tion of concrete surfaces. 362.2R-4ACI COMMITTEE REPORT 3.1.3 DelaminationsDelamina
46、tions are fractures of the concrete, parallel to the surface, usually resulting from cor- rosion of the reinforcing steel parallel to the surface in the concrete. Extensive concrete delaminations (5 to 10% of the surface area visually deteriorated) are an indication of ad- vanced deterioration. 3.1.
47、4 SpallingSpalling is the fracturing of the outer sur- face of concrete. It can be caused by corrosion of embedded reinforcement, which can produce internal pressures exceed- ing the tensile strength of the concrete. It can also be caused by impact. Spalling typically creates cavities 25 mm (1 in.)
48、or more in depth with rough surfaces. Spalling tends to create conditions conducive to progressive deterioration of the structural concrete. Spalling on the top surfaces of the deck can lead to rapid deterioration due to the ponding of water combined with the reduced concrete cover over the reinforc
49、- ing steel. Fig. 3.3 shows how corrosion-induced stresses can lead to concrete spalling and deterioration. 3.1.5 CrackingThere are many possible causes of crack- ing in concrete (Fig. 3.4). For most nonprestressed deck sys- tems, well-distributed fine cracks are considered normal and no treatment is required. Refer to ACI 224R for discussions of crack width. Fig. 3.3Corrosion-induced spalling process. Corrosion-induced stress has multiple effects on structural integrity affecting maintenance and serviceability: surface spalling
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