Knox Jeff L. LaRue Arthur W. McKinney Colin T. Milberg Peter J. Ruttura Michael J. Schneider Thomas J. Downs Ron Eldridge Michael W. Lee Michael L. Leming William R. Nash Bob L. Payne Bruce A. Suprenant Michael A.
West Specification synopsis: This specification provides standard tolerances for concrete construction and materials. This document is intended to be used by specification writers and ACI committees writing standards as the reference document for establishing tolerances for concrete construction and materials.
Keywords: architectural concrete; concrete; construction; drilled piers; formwork; foundation; mass concrete; pier; precast concrete; prestressed concrete; reinforced concrete; reinforcement; specification; splice; tilt-up concrete; tolerances. ACI Specification and Commentary are presented in a sideby-side column format, with code text placed in the left column and the corresponding commentary text aligned in the right column.
To distinguish the specification from the commentary, the specification has been printed in Helvetica, which is the typeface for this paragraph. ACI Committee Reports, Guides, Manuals, 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 of its content and recommendations and who will accept responsibility for the application of the material it contains. The American Concrete Institute disclaims any and all responsibility 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 contract documents.
The Commentary is printed in Times Roman, which is the typeface for this paragraph. The commentary is not a part of ACI Specification 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, or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.
Section 15—Tilt-up concrete, p. No structure is exactly level, plumb, straight, and true. Tolerances are a means to establish permissible variation in dimension and location, giving both the designer and the contractor limits within which the work is to be performed.
They are the means by which the designer conveys to the contractor the performance expectations upon which the design is based or that the project requires. Such specified tolerances should reflect design assumptions and project needs, being neither overly restrictive nor lenient. Necessity rather than desirability should be the basis of selecting tolerances. They are based on normal needs and common construction techniques and practices. Specified tolerances at variance with the standard values can cause both increases and decreases in the cost of construction.
Economic feasibility—The specified degree of accuracy has a direct impact on the cost of production and the construction method. In general, the higher degree of construction accuracy required, the higher the construction cost, and the lower the degree of construction accuracy, the higher the cost of required repairs.
Relationship of all components—The required degree of accuracy of individual parts can be influenced by adjacent units and materials, joint and connection details, and the possibility of the accumulation of tolerances in critical dimensions.
Construction techniques—The feasibility of a tolerance depends on available craftsmanship, technology, materials, and project management.
Compatibility—Designers are cautioned to use finish and architectural details that are compatible with the type and anticipated method of construction. The finish and architectural details used should be compatible with achievable concrete tolerances. ACI , , , , , , , Special structures ACI , , , , , , Materials Tolerances in this specification are for typical concrete construction and construction procedures and are applicable to exposed concrete and to architectural concrete.
Materials that interface with or connect to concrete elements may have tolerance requirements that are not compatible with those contained in this document. This specification does not apply to specialized structures, such as nuclear reactors and containment vessels, bins, prestressed circular structures, and single-family residential construction.
It also does not apply to precast concrete or to shotcrete. Tolerances for specialized concrete construction that is outside the scope of this specification shall be specified in Contract Documents. The Contractor, subcontractors, material suppliers, and other key parties shall attend. An example of a specific application that uses a multiple of toleranced items that together yield a toleranced result is the location of the face of a concrete wall.
The wall has a tolerance on location Section 4. The application of the location tolerance Section 4. Similarly, the tolerance on member thickness Section 4. If the base of the wall is incorrectly located by the maximum amount allowed by Section 4. Refer to Fig. Tolerances are measured from the points, lines, and surfaces defined in Contract Documents.
If application of tolerances causes the extension of the structure beyond legal boundaries, the tolerance must be reduced. The most restrictive tolerance controls. Individual tolerances are unique to their specific application and should not be combined with other tolerances to form a tolerance envelope. The separately specified tolerances must remain separate and not cumulative. Each tolerance stands alone when evaluating the acceptability of concrete construction.
Minus — tolerance decreases the amount or dimension to which it applies, or lowers a deviation from level. Definitions provided here complement that resource. Contract Documents—a set of documents supplied by the Owner to the Contractor that serve as the basis for construction; these documents contain contract forms, contract conditions, specifications, drawings, addenda, and contract changes.
Contractor—he person, firm, or entity under contract for construction of the Work. Deviation from plane is used to determine the rate of change of adjacent points slope tolerance occurring within the tolerance envelope. In this fashion, the slope and smoothness of surfaces and lines within a tolerance envelope are controlled.
Abrupt changes such as offsets, saw-toothing, and sloping of lines and surfaces properly located within a tolerance envelope may be objectionable for exposed concrete.
The acceptable relative alignment of points on a surface or line is determined by using a slope tolerance. Effective use of a slope tolerance requires that the specific distance over which the slope is to be measured is established, and that the measurement device only contacts the surface at this specific distance.
Project Drawings—graphic presentation of project requirements. Project Specification—the written document that details requirements for the Work in accordance with service parameters and other specific criteria. Work—the entire construction or separately identifiable parts thereof required to be furnished under Contract Documents. Because these documents are revised frequently, the reader is advised to contact the proper sponsoring group if it is desired to refer to the latest version.
Louis, MO www. West Conshohocken, PA www. Schaumburg, IL www. Adams St. For bars No. Figure courtesy of Concrete Reinforcing Steel Institute. For all end-bearing splice assemblies, refer to Fig. For all bar sizes, specified minimum inside radius of bend When member depth or thickness is over 4 in. When member depth or thickness is over 12 in. Before placement of concrete, inspection of reinforcing bars for conformance to specified placement tolerances may involve measurements to formwork or soil.
An absolute limitation on one side of the reinforcement placement is established by the limit on the reduction in cover. In addition, the allowable tolerance on spacing should not cause a reduction in the specified number of reinforcing bars used. Designers are cautioned that selecting a beam width that exactly meets their design requirements may not allow for reinforcement placement tolerance.
This sometimes happens when lapspliced bars take up extra space and cannot accommodate the placement tolerance. Where reinforcement quantities and available space are in conflict with spacing requirements of these sections, the Contractor and designer might consider bundling a portion of the reinforcement.
Bundling of bars requires approval of the designer. Distance between reinforcement shall not be less than the greater of the bar diameter or 1 in. For bundled bars, the distance between bundles shall not be less than the greater of 1 in. Element depth or thickness over 24 in. Slab behavior is relatively insensitive to horizontal location of tendons. Element depth or thickness over 8 in. Element depth or thickness more than 24 in At discontinuous ends of other elements At other locations When element depth is over 8 in.
The total number of dowels shall not be fewer than that specified. Vertical deviation Assembly dimension greater than 12 in. Table 2. Concrete slump should include a tolerance that allows for both plus or minus deviations so that concrete slumps are not underdesigned to avoid rejection.
Specified slump 3 in. Specified slump more than 3 in Where slump is specified as a single value Specified slump 2 in. Specified slump more than 2 in. Specified slump more than 4 in Where slump is specified as a range In addition, it is difficult to measure high slumps accurately.
Consideration should be given to eliminating a maximum slump when a HRWRA is used to achieve flowing concrete. The slump specified should always be evaluated to determine if it is suitable for delivery, placing, and reinforcement clearance. The range should be adequately wide to accommodate the preceding. The allowable deviation for the location of foundations or piers is governed by the dimension of the foundations or piers with an absolute limit, depending on whether the foundations or piers support concrete or masonry.
Horizontal deviation of the as-cast edge: Where dimension is 8 ft or more Where dimension is less than 8 ft Determines the location of any point on the top surface of a footing relative to the specified plane. Refer to Fig R3. Determines the permissible size of a foundation. Specified tolerances apply to the completed concrete element.
Horizontal deviation from plan dimension. Excavation shall be measured before concrete placement. Tolerance shall apply at all locations. Where dimension is 2 ft or less Where dimension is more than 2 ft Between the top of foundation and a height of 83 ft 4 in. The tolerance for the outside corner of exposed corner columns and for contraction joint grooves in exposed concrete is more stringent. For lines, surfaces, corners, and arrises: the lesser of 0.
This section shall not be used to evaluate local departure from a specified plane or form irregularities. Refer to Section 4. For the outside corner of an exposed corner column and grooves in exposed concrete: the lesser of 0.
This specification provides standard tolerances for concrete construction and materials. A Ai Checklist is included as a preface to, but not forming a part of, Standard Specification This that you are always up-to-date and saves you both time and money.
Section 8 — Mass concrete structures other than buildings, p. When member size is over 12 in. Over 40 ft but not over 60 ft. Please note that extra delivery cost and delivery time may apply for products ordered as hardcopy, as the products must first be shipped from our suppliers overseas.
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