Regulatory Guide 1.55
| ML13064A106 | |
| Person / Time | |
|---|---|
| Issue date: | 06/30/1973 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| References | |
| RG-1.055 | |
| Download: ML13064A106 (3) | |
JUNE 1973 U.S. ATOMIC ENERGY COMMISSION
R EG U LATO RY U.U10E
DIRECTORATE OF REGULATORY STANDARDS
'Oft 0 8 HN'
REGULATORY GUIDE 1.55 CONCRETE PLACEMENT IN CATEGORY I STRUCTURES
A. INTRODUCTION
the only method of assuring a quality concrete structure is through good planning and control of the placement General Design Criterion 1, "Quality Standards and of concrete and all items embedded in it.
Records," of Appendix A to 10 CFR Part 50, "General Design Criteria for Nuclear Power Plants," requires that Proper planning and control require that the sturctures, systems, and components important to safety designer and the constructor be familiar with each be designed, fabricated, erected, and tested to quality other's requirements. The designer should be conscious standards commensurate with the importance of the of the practicality of the design from the constructor's safety function to be performed. Appendix B to 10 CFR point of view, while the constructor. should recognize Part 50, "Quality Assurance Criteria for Nuclear Power the consequences of deviating from conditions specified Plants and Fuel Reprocessing Plants," requires that by the designer. It is essential that the two parties meet measures be established to assure design control, at an early stage and discuss how these structures will be material control, special processes control, and constructed. Methods that seem expedient or inspection and test controls. Appendix B also requires economical .aW later turn out to have serious adverse that activities affecting quality be accomplished under consequences.
suitably controlled conditions. This guide describes some acceptable bases for implementing the above To date the standards applied to quality control of requirements with regard to the placement of concrete concrete in nuclear power plants have been based on in Category i structures.1 The Advisory Committee on standards for conventional- building structures. Mass Reactor Safeguards has been consulted concerning this concrete standards have generally been considered guide and has concurred in the regulatory position. inapplicable for nuclear construction because the quality level needed for each cubic yard of concrete placed more nearly approximates the quality level required for
B. DISCUSSION
relatively slender sections of conventional buildings.
Many standards, manuals, codes, and articles exist At the same time, it is necessary to recognize that in which address the proper designing, handling, and placing deep foundation mats and thick-walled placing of concrete. Nevertheless, concrete continues to structures or components in nuclear power plants, there be improperly placed in nuclear power plants, resulting are placement problems (e.g., shrinkage and control of in Iengthly delays and much wasted effort. In particular, heat of hydration during curing) also found in mass the presence of numerous concrete voids which have concrete pours. Consequently, consideration must be been detected at or near the surfaces of nuclear given to the problems and practices of mass concrete containment bulkdings raises concern about the density pours, that are applicable to nuclear power plant of portions of these and other concrete structures that structures.
cannot readily be inspected. For such unaccessible areas, A list of standards, codes, papers, and other references which are generally directed toward the
'Structures, systems, and components of a nuclear power quality placement of concrete is given in Appendix A of plant are designated as Category I if they are designed to withstand the effects of the Safe Shutdown Earthquake (SSE) this guide. These documents, appropriately selected by and remain functional (see Regulatory Guide 1.29, "Seismic the user for the particular application under Design Classification"). consideration, provide useful guidance for the planning USAEC REGULATORY GUIDES Copies of published guides troy be obtained by request indicating the divisions desired to the US. Atomic Energy Commission, Washington, D.C. 20645, Regulatory Quides we issued to describe and maike available to the -public Attention: Director of Regulatory Standerds. Comments and suggestions for methods acceptable to the AEC Regulatory staff of implementing specific parts of improvements in those guides are encouraed and should be sent to the Secretary the Commission's regulations, to delineate techniques used by the staff in of the Commission, US. Atomic Energy Commission, Washington, D.C. 20645, etluating specific problems or postulated accidents, or to provide guidance to Attention: Chief, Public Proceedings Staff.
essplimnts. Regulatory Guides are not substitutes for regulations and compliance with them is not required. Methods and solutions different from those set out in The guides are issued in the following ten broad divisions:
the guides will ta accaptable if they provide e bais for the findings requisite to the issuensc or continuance of a permit or license by the Commission. 1. Power Reactors
6. Products
2. Research and Test Reactors
7. Transportation
& Fuels and Materials Facilities a. Occupetional Health Published guides will be revised periodically, es appropriate, to accommodate 4. Environmental and Siting 9. Antitrust Review comnnts andOto reflect new information or experience. S. Materials and Plant Protection 1
0. General
and coordinating activities prerequisite to concrete considering congestion and interference from other placement. However, the listing of these references in an embedded items and reinforcing as well as the type of appendix to this guide does not constitute a blanket concrete to be placed (slump, aggregate size, whether endorsement of their contents. preplaced appregate is used, etc.).
(3) Locations of construction joints-locations Individual material specifications (ASTM, etc.) are of acceptable construction joints should be noted, as not included in Appendix A of this guide, since this well as any "windows" in congested reinforcing patterns guide addresses only the requirements for proper needed for placing the concrete. Followup coordination planning and coordination in placing concrete so as to and revision with the constructor is essential. Factors for avoid the recurring problems of voids, cracks, and bulges consideration include: type and quantity of concrete to which have been experienced in nuclear power plant be placed; shrinkage and creep; accessibility; cleanout construction. capability before and after placing the concrete; and acceptability from a strength or functional point of
C. REGULATORY POSITION
view. Alternative joint locations should be available to the constructor in the event that concrete placement The regulatory positions given below for the cannot be completed as planned and started.
applicant, the designer, and the constructor together b. In addition to checking the drawings as noted with the guidance from appropriate documents listed in above, the designer should assist the constructor as Appendix A of this guide represent a minimum basis for necessary in preplanning placement of reinforcement, assuring compliance with the Commission's regulations embedded items, and concrete as well as the sequence to in Appendices A and B to Part 50 and should be be followed in placing concrete. The designer should also supplemented as necessary in the appropriate quality follow the construction while it is in progress, including, assurance programs and project specifications. (As an if necessary, occasional site visits, and be available for example, in several areas ACI 301 lists stricter concrete assistance in resolving unanticipated field placement sampling requirements than ACI 318. In such cases, the problems that might affect the structural or functional relevant provisions of ACI 301 should govern in the integrity of the structure. Field generated revisions interest of obtaining the best concrete quality practical should be approved by the designer.
under existing industry practices.)
3. Constructor. In addition-to the coordination noted
1. Applicant. The applicant's quality assurance above, preplanning by the constructor is necessary for:
program should ensure that early and regular a. Cleanness-assuring cleanness of formed area communication is established between the designer and prior to and during concrete placement, including access constructor. Rapid access to the designer should be provisions for inspection and cleanout operations.
possible for the constructor in the event that a field b. Installations-installations of reinforcing bars, condition requires immediate consultation with the splices, embedded items, formwork, and construction designer, such as relocation of a construction joint or an joint barriers should be checked prior to placing embedded item while placing of concrete is in progress. concrete.
Conversely, the designer should have rapid access to the c. Placement layout-practicality of construction constructor in the event that late revisions must be made joint locations, venting of potential air pockets to in the field because of changes in design. Under the prevent voids, access to congested or confined areas, provisions of Appendix B to Part 50, the applicant's sequence of placement.
quality assurance program should also ensure the d. Equipment-availability of proper equipment in implementation of sections C.2. and C.3. below. good operating condition and in sizes and quantities needed (vibrators, chutes, etc.). Sufficient spares (parts
2. Designer or equipment) should be readily available so that loss or a. The designer should check the design and shop breakdown of equipment will not interrupt the placing drawings for practicality of: of concrete and result in unplanned cold joints.
(1) Placement of reinforcing bars-continuity, e. Personnel-sufficient training and experience in congestion, interference, non-planar geometric bending the proper use' of all equipment (especially vibrators)
and placing requirements, splice locations and their involved in the placing of concret
e. Also sufficient
.effect on minimum bar spacing. supervisory knowledge and experience to enable the
(2) Location of embedded items-feasibility of concrete placement to be completed ih accordance with placing concrete completely around the item, specifications.
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APPENDIX
BIBLIOGRAPHY OF USEFUL REFERENCES
1. ACI 318-71 Building Code Requirements for 9. ACI Committee 207 "Mass Concrete for Dams and Reinforced Concrete (and Comraentary)-Chapter Other Structures" ACI Journal April 1970, pp.
5, "Mixing and Placing Concrete". 273-309.
2. ACI 301-72 Specifications for Structural Concrete 10. "Cracking Controlled in Massive, Reinforced for Buildings. Structural Concrete by Application of Mass Concrete Practices." L. H. Tuthill and R. H. Adams,
3. ACI 305 72 Recommended Practice for Hot ACI Journal August 1972, pp. 481-491.
Weather Concreting.
11. ACI/ASME Proposed Standard-Code for Concrete
4. ACI 306-66 Recommended Practice for Cold Reactor Vessels and Containments (ASME Sect. III,
Weather Concreting. Division 2) CB 4200, CC 4200 and CB 4340-4370,
CC 4340-4370.
5. ACI 308-71 Recommended Practice for Curing Concrete. 12. ANSI N45.2.5-1972 (proposed) Supplementary Q.A. Requirements for Installation, Inspection, and Testing of Structural Concrete and Structural Steel
6. ACI 347-68 Recommended Practice for Concrete During the Construction Phase of Nuclear Power Formwork. Plants.
7. ACI 614-(Proposed Revision) Recommended 13. Concrete Manual, U.S. Bureau of Reclamation, Practice for Measuring, Mixing, Transporting and Denver; Seventh Edition, 1966.
Placing Concrete.
14. Standard Practice for Concrete (EM 1110-2-2000);
8. ACI Special Publication No. 4-Formwork for Dept. of the Army, Office of Chief of Engine rs, Concrete. Washington, D.C.; November 1971.
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