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1、R! 0bb2949 0552923 494 AC1 362.2R-00 Guide for Structural Maintenance of Parking Structures Reported by AC1 Committee 362 B ational“ american concrete institute P.0, BOX 9094 FARMINGTON HILLS, MICHIGAN 48333-9094 Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=I
2、HS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 01:20:06 MSTNo reproduction or networking permitted without license from IHS -,-,- I Obb2949 0552724 320 M First Printing, July 2000 Guide for Structural Maintenance of Parking Structures Most AC1 Standards and committee repor
3、ts are gathered together in the annually revised AC1 Manual of Concrete Practice. The several volumes are arranged to group related material together and may be purchased individually or in setS.The AC1 Manual of Concrete Practice is also available on CD-ROM. reports in the general areas of material
4、s and properties of concrete, construction practices and inspection, pavements and slabs, struc- tural design and analysis, structural specifica- tions, and special products and processes. A complete catalog of all AC1 publications is AC1 Committees prepare standards and available without charge. Am
5、erican Concrete Institute P.O. Box 9094 Farmington Hills, MI 48333-9094 AC1 Certification Programs The final quality of a concrete structure depends on qualified people to construct it. AC1 certification pro- grams identify craftsmen, technicians, and inspectors who have demonstrated their qualifica
6、tions. The follow- ing programs are administered by AC1 to fulfill the grow- ing demand in the industry for certified workers: Concrete Flatwork Finisher Concrete Flatwork Technician Concrete Field Testing Technician-Grade I Concrete Strength Testing Technician Concrete Laboratory Testing Technician
7、-Grade I Concrete Laboratory Testing Technician-Grade II Concrete Construction lnspector-ln-Training Concrete Construction Inspector Concrete Transportation Construction Inspector-ln- Training Concrete Transportation Construction Inspector This document may already contain reference to these AC1 cer
8、tification programs, which can be incorporated into project specifications or quality control procedures. If not, suggested guide specifications are available on request from the AC1 Certification Department. Enhancement of AC1 Documents The technical committees responsible for AC1 committee reports
9、 and standards strive to avoid ambiguities, omis- sions, and errors in these documents. In spite of these efforts, the users of AC1 documents occasionally find information or requirements that may be subject to more than one interpretation or may be incomplete or incor- rect. To assist in the effort
10、 for accuracy and clarity, the Technical Activities Committee solicits the help of indi- viduals using AC1 reports and standards in identifying and eliminating problems that may be associated with their use. Users who have suggestions for the improvement of AC1 documents are requested to contact the
11、 AC1 Engi- neering Department in writing, with the following infor- mation: 1. Title and number of the document containing the problem and specific section in the document; 2. Concise description of the problem: 3. If possible, suggested revisions for mitigating the problem. The Institutes Engineeri
12、ng Staff will review and take appropriate action on all comments and suggestions received. Members as well as nonmembers of the insti- tute are encouraged to assist in enhancing the accuracy and usefulness of AC1 documents. Copyright American Concrete Institute Provided by IHS under license with ACI
13、 Licensee=IHS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 01:20:06 MSTNo reproduction or networking permitted without license from IHS -,-,- Obb2949 0552925 2b7 AC1 362.2R-O0 Guide for Structural Maintenance of Parking Structures Reported by AC1 Committee 362 Thomas G. Wei
14、l Thomas J. Downs* Chairman Secretary James C. Anderson Keith W. Jacobson* car1 A. Peterson* Ralph T. Brown Norman G. Jacobson, Jr. Suresh G. Pinjarkar Girdhari L. Chhabra Howard R. May Predrag L. Popovic Anthony P. Chrest Gerald J. McGuire H. Carl Walke? JO Coke Martin B. Mikula Steward C. Watson T
15、homas J. D Arcy* David C. Monroet Bertold E. Weinberg Bons Dragunsky Thomas E. Nehil *Denotes members of subcommittee who prepared the document. Subcommittee chairman. This guide is intended IO assist parking structure owners, operators, and the consultants who advise them in developing preventive m
16、aintenance pro- grams for parking structures. It presents tjpical maintenance concerns and suggests ways of addressing them. The guide summarizes information regarding structural, operational. aesthetic, and routine maintenance for parking structures. Design sugges- rions to minimize maintenance are
17、 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 AC1 362.IR for more complete information regarding design issues related to a parking
18、structure I s 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; prestressed; ramp; scaling; sealant; sealer;
19、 snow removal; spalling. AC1 Committee Reports, Guides, Standard Practices, and Commentaries are intended for guidance in planning, designing, executing, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limitations o
20、f its content and recommendations and who will accept re- sponsibility for the application of the material it contains. The American Concrete Institute disclaims any and all re- sponsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom. Refere
21、nce to this document shall not be made in con- tract documents. If items found in this document are de- sired by the ArchitectEngineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the ArchitectEngineer. CONTENTS Chapter 1-Introduction, p.
22、362.2R-2 Chapter 2-Developing a maintenance program, p. 362.2R-2 2.1-The project maintenance manual 2.2-Periodic inspections 2.3-Preventive maintenance 2.4-Conditional appraisals Chapter 3-Deterioration problems associated with parking structures, p. 362.2R-3 3.1-Concrete-related deterioration 3.1.1
23、-Scaling 3.1.2-Corrosion 3.1.3-Delaminations 3.1.4-Spalling 3.1 S-Cracking 3.1 . 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. If a project maintenance manual ex
24、ists, it is a good idea to become familiar with the manual to develop a com- prehensive maintenance program. 2.2-Periodic inspections A walk-through visual inspection should be made at least annually to provide an overview of the structures general condition. Problems should be noted in a concise re
25、port, rec- ommending further investigation of specific items if re- quired. The inspection should be conducted by an engineer experienced in structural condition assessment of parking structures. A visual inspection does not involve physical test- ing. Maintenance personnel with proper checklists an
26、d day- to-day experience of operating the structure can also conduct a visual inspection of nonstructural maintenance concerns. Appendix C provides a checklist of specific items that should be observed during a visual maintenance inspection. 2.3-Preventive maintenance Preventive maintenance should r
27、educe 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 debris, wash-downs with water, sealin
28、g 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.Aondition appraisals A condition appraisal should be performed if extensive de- terioration or unexplain
29、ed 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. Typically, the appraisal focuses on t
30、he 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 of corrosion and bond loss of the rein
31、forcement and those that quantify the amount and extent of chloride in- gress into the concrete. See AC1 201.1R for additional infor- mation regarding concrete durability. Testing may include Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=IHS Employees/11111110
32、01, User=listmgr, listmgr Not for Resale, 03/05/2007 01:20:06 MSTNo reproduction or networking permitted without license from IHS -,-,- Obb2Li 0552927 03T M GUIDE FOR STRUCTURAL MAINTENANCE OF PARKING STRUCTURES 362.2R-3 compressive strength, chain dragging, and half-cell testing to locate active co
33、rrosion and delamination, and chloride-ion content. In addition, petrographic analysis can be done to identify specific concerns regarding the makeup of the con- crete. Information gathered from the condition appraisal, along with resulting lab analyses, should be reviewed by an engi- neer experienc
34、ed with structural-condition appraisals. If necessary, a materials consultant can confirm the causes of deterioration. These experts should provide a report with specific recommendations, including restoration priorities, options, and repair budgets. The owner should maintain accurate maintenance an
35、d in- spection records to provide historical information that can assist in future appraisals of deterioration and identify poten- tial problems observed. CHAPTER 3-DETERIORATION PROBLEMS ASSOCIATED WITH PARKING STRUCTURES The implementation of a proper maintenance program re- quires an understandin
36、g of the deterioration mechanisms and their symptoms. Most deterioration involves water in- trusion and corrosion of reinforcement. Problems that are left unattended during the early stages of their development can lead to safety hazards for users, in- creased liability for owners, and can require e
37、xpensive re- pair programs for correction. Structural maintenance requirements are those actions necessary to preserve, re- store, and enhance structural members and improve or en- hance protective functions of various waterproofing and anticorrosion systems. See AC1 201.1R, 222R, and 224R for addit
38、ional information regarding deterioration mechanisms briefly described in this guide. 3.1 -Concrete-related deterioration Concrete-related deterioration is often associated with scaling, spalling, joint failure, or cracking of the concrete members. Delamination of concrete, however, is not a pre- re
39、quisite for concrete-related deterioration. Sections 3.1.1 through 3.1.7 discuss various deterioration mechanisms. 3.1.1 Scaling-Scaling is the disintegration of cement paste at the concrete surface. Commonly associated with cy- cles of freezing and thawing, it results in progressive deteri- oration
40、. Severe scaling can result in a loss of concrete surface integrity to depths of more than 25 mm (1 in.). Scal- ing in deck slabs can create depressions that pose tripping hazards and create ponding areas that can lead to further de- terioration. See Fig. 3.1. 3 . 1 . 2 Corrosionrorrosion is an elec
41、trochemical 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 process. Moisture and oxygen also play a direct role. Corrosion c
42、an lead to serious deterioration and repair problems. As corrosion progresses, the corrosion byproducts occupy a greater volume than the original metal, creating internal pressure on the concrete that can eventually lead to cracking, delamination, and breaking Fig. 3.1-Scaling is deterioration of co
43、ncrete sulfaces usu- ally caused by exposure to freeze-thaw cycles. Fig. 3.2-Corrosion o f reinforcement can lead to deteriora- tion o f concrete surjces. of the concrete substrate. Corrosion of unbonded post-ten- sioning tendons represent a special case. Post-tensioned tendons can corrode or even f
44、ail without cracking or delaminating the surrounding concrete. A post- tensioned tendon failure is often accompanied by the erup- tion of the tendon either at the tendon end or through the con- crete slab. Other post-tensioning problems to look for include exposed tendon sheathing or dislodging of p
45、ost-tensioning anchors. Mitigating the corrosion process should be a priority of any maintenance program. The most practical way 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 st
46、ructure (Fig. 3.2). Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=IHS Employees/1111111001, User=listmgr, listmgr Not for Resale, 03/05/2007 01:20:06 MSTNo reproduction or networking permitted without license from IHS -,-,- 362.2R-4 I I Obb2949 0552928 T7b = A
47、C1 COMMITTEE REPORT 2. RU- BUUDS U? AROUND STEEL CAUSING BICE STRESS OR ?RESURE. CRAClaNGOCCURS M D MIGRATES i0 SURFACE UNDER INFLUENCE OF TRAFFIC ACI1OWANDFRCEZCIHAW CYCLING DLLAMMATION OR FRAcnnu CAUSING ?RESSuRE 3- CON- B m M AWAY LUyINC OPEN SPAU OR ?MAOLE. FULL CIR. mFXCNcl! CORROSION rROCEEDS
48、UNYU comum DEBONDING O? ReMmRcwc o c - : SECTTON LOSS ACcELER4IED. SALT WAEJt CON“U0US CORROSION Fig. 3.3-Corrosion-induced spalling process. Corrosion-induced stress has multiple effects on structural integrity affecting maintenance and serviceability: suace spalling can occur; reinforcement loses
49、cross section affecting stress distribution; reinforcement loses bond, causing loss o f monolithic interaction; and concrete cross section loss impairs load-carrying capaciq. See AC1 222.R for a more complete discussion of the corro- sion process and its causes, and AC1 423.4R on corrosion and repair of unbonded single-strand tendons. 3.1.3 Delaminations-Delaminations are fractures of the concrete, parallel