The Specifier should refer to the Mandatory Requirements Checklist. Class D Surface The two surface characteristics thought to be of greatest importance for concrete floors are flatness and levelness. Flatness can be described as bumpiness of the floor, and is the degree to which a floor surface is smooth or plane. Levelness is the degree to which a floor surface parallels the slope established on the project drawings.

Two methods are identified for use in the evaluation of floor surface finish tolerances. The F-Number System uses data taken at regular intervals along lines located in random locations on the test surface. The described methods use different criteria to evaluate the asconstructed data. Therefore, it is important that the Specifier select the method most applicable to the end user of the floor.

The Waviness Index may be used instead of the two methods identified in Sections 4. Before contracting to build to any floor tolerance specification, it is suggested the constructor evaluate data from tests of its own floors. Data should be processed using the proposed floor tolerance specification to confirm an understanding of the specific approach and its implications on proposed construction means and methods.

Specifiers may require the constructor to demonstrate proven ability by testing an existing floor slab installed by the constructor.

Each of the methods described herein will yield a slightly different result. Each of the described approaches uses a different method to evaluate flatness.

The manual straightedge and computerized simulation of the manual straightedge methods both use maximum offsets from chords of varying lengths up to 10 ft. To develop an understanding of the relationship among these approaches, the committee undertook a study of six groups of individual profiles each total. The profiles included all quality levels likely to be produced using current construction techniques; each of the profiles was ft long.

Table R4. Evaluation of the results resulted in the tolerance values contained in Sections 4. Floor surface classifications shown in Sections 4. Although there is no direct correlation among the described tolerancing methods, similarly classified floors in Sections 4. Floor surfaces in the conventional category can be routinely produced using strikeoff and finishing techniques that include no restraightening operations after initial strikeoff.

This classification of floor surface is generally not compatible with floor coverings such as carpeting and vinyl flooring. Conventional floor surface tolerances are appropriately applied to areas such as mechanical rooms, nonpublic areas, or surfaces under raised computer flooring or thick-set tile. The moderately flat classification of surface tolerances will routinely require the use of float dish attachments to the power float machines or some restraightening of the concrete surface during finishing operations to consistently achieve flatness requirements.

The moderately flat surface can routinely be produced by using a wide bull float 8 to 10 ft to smooth the concrete and a modified highway straightedge Table R4. Conventional 20 0. The use of a rider with float dishes attached to the trowel blades can reduce the amount of restraightening required by the modified highway straightedge.

An appropriate use of floor surfaces with this classification would be carpeted areas of commercial office buildings or industrial buildings with low-speed vehicular traffic. Flat floor tolerances are appropriate for concrete floors under thin-set ceramic, vinyl tile, or similar coverings. Flat floor tolerances are also appropriate for use in warehouses employing conventional lift trucks and racks.

The flat classification requires restraightening after floating and is the highest feasible tolerance level for suspended slabs. Very flat floor tolerances are generally restricted to high-end industrial applications, such as might be required for successful operation of high-speed lift trucks, air pallets, or similar equipment.

Multiple restraightenings in multiple directions following both the floating and initial finishing phases are required to produce floors conforming to very flat tolerances. The use of a laser screed or rigid edge forms up to 30 ft apart can achieve the required degree of levelness.

The super-flat category is the highest quality random traffic floor surface classification that can be routinely produced using current technology. Only skilled contractors, using sophisticated equipment, will be able to achieve this level of quality. Restraightening operations for this floor category are more rigorous than that described for the very flat category.

The super-flat random traffic category is only appropriate for limited applications, such as TV production studios. Another type of super-flat floor surface, one that falls outside the scope of random traffic specifications, is that which is required for defined traffic applications, such as narrow aisle industrial warehouse floors. The aisle width in these installations is typically about 5 ft wide, and the narrow clearance between the vehicles and racks requires construction of an extremely smooth and level surface.

The tolerance requirements normally dictate strip placement of concrete using closely spaced rigid forms approximately 15 ft on center , but they can occasionally be achieved without narrow strip placement by skilled contractors using sophisticated equipment.

The evaluation of the super-flat defined traffic surface classification requires specialized techniques that should be agreed on by all parties before construction. The test method should measure: 1. The maximum transverse elevation difference between wheel tracks; The maximum elevation difference between front and rear axle; and The maximum rate of change per foot for 1 and 2 as the vehicle travels down the aisle.

The remedy for noncompliance with specified defined flatness tolerances should be included in specification language. For random traffic slabs-on-grade, the remedy can range from liquidated damages, to localized grinding, to application of a topping, to removal and replacement, depending on the purpose for which the slab is being installed.

The remedy for defined traffic installations is generally grinding of high spots. All slabs will shrink; joints and cracks in slabs-on-ground will curl with time, resulting in a surface that is less flat with the passage of time. If the needs of the user are such that a delay in testing is necessary to allow successful installation of subsequent Work, this requirement for delayed testing should be clearly stated in the specifications.

Survey lines should be parallel to the direction of slope. In instances where the Specifier chooses to provide a tolerance at construction joints, specific provisions for data collection should be included in the Project Specifications.

The system evaluates the levelness of a floor surface by measuring elevation changes relative to a horizontal plane and between points separated by a distance of 10 ft. Higher numbers indicate better quality in the surface characteristic being reported. Consequently, after the entire floor has been installed, the system permits the immediate calculation of liquidated damages based on the final aggregate areas defective relative to either SOFF or SOFL whichever yields the larger penalty.

These variations can be caused by normal occurrences, such as inconsistent setting time of concrete, changes in ambient conditions, or delays in delivery or placement of the concrete. Acceptance or rejection of a minimum local area requires that data collection within the minimum local area in question meet the requirements of ASTM E Smaller gaps between the straightedge and supporting surface are indicative of higher flatness quality.

This method is not sufficiently precise to evaluate very flat and super-flat categories. Table 4. A sample is a single placement of the straightedge. The Specifier may provide alternative procedures as long as specific testing requirements and acceptance criteria are established.

Test results should be reported in a manner that will allow the data to be verified or the test to be replicated. When using this approach to evaluate floor surfaces, levelness is subject to the provisions of Section 4. Data collection procedures and evaluation of data shall comply with the requirements established in the Contract Documents or Section 4.

Data are taken using an instrument other than a straightedge and processed using a computer to produce results similar to that achieved using a manual straightedge. The flatness is evaluated by moving a simulated 10 ft long straightedge along each data line at 1 ft intervals. No ASTM standard has been developed to govern evaluation of a floor surface using this procedure, so the Specifier should provide specific testing requirements and acceptance criteria as described in the Mandatory Requirements Checklist.

Results should be reproducible. The Specifier is advised that current available software for computerized simulation of a freestanding 10 ft straightedge does not meet the requirements of Section 4. Each survey line used in the RMS levelness calculation shall be parallel with the others and all lines shall be in the direction of the pitch or tilt.

Tolerances in this standard apply to cast-in-place concrete elements that interface with precast concrete elements. Tolerances for tilt-up concrete are specified in Section More than 36 in. Greater than 12 in Refer to ACI Heights greater than ft Edges of openings, sleeves, and embedments greater than 12 in More than ft Horizontal deviation Concealed surfaces Refer to commentary Sections R4. Concealed flatwork and formed surfaces Decrease thickness: greater of 2. On highway plans, dimensions are usually given in hundredths of a foot.

Inches are used here to conform to the rest of this document. Other exposed surfaces Greater than 18 in. In any 10 ft of height, the geometric center of the chimney or cooling tower element shall not change more than For pipe with an internal diameter greater than 42 in.

For pipe with an internal diameter greater than 72 in. For pipe with an internal diameter from 42 in. Each additional 10 ft or part thereof Not to exceed Each additional 6 ft or part thereof The lesser of 0. Top of non-exposed individual panel Difference at top of adjacent exposed panels.. Difference at top of adjacent non-exposed panels Base of erected panel Bearing plates or seats Inserts, bolts, sleeves Flashing reglets Lifting inserts Weld plates From building grid datum, measured at base of panel Bearing plates and seats Edge of panel from centerline of panel Per 10 ft Corners, exposed and non-exposed Variation in joint width over length of panel The Specifier, however, must select the items and include them separately in the Project Specifications.

General notes G1. ACI Specification is intended to be used by reference or incorporation in its entirety in the Project Specification. Do not copy individual Sections, Parts, Articles, or Paragraphs into the Project Specification, because taking them out of context may change their meaning. If Sections or Parts of ACI Specification are copied into the Project Specification or any other document, do not refer to them as an ACI specification because the specification has been altered.

Each technical section of ACI Specification in this Standard associated with items in the Mandatory Requirements Checklist are accompanied by text indicating an item in the section is specified in the Contract Documents. ACI Specification is written to the Contractor. This Foreword is included for explanatory purposes only; it does not form a part of ACI Specification ACI Specification may be referenced by the Specifier in the Project Specification for any building project, together with supplementary requirements for the specific project.

Responsibilities for project participants must be defined in the Project Specifications. ACI Specification cannot and does not address responsibilities for any project participant other than the Contractor. The Optional Requirements Checklist identifies Specifier choices and alternatives. The Checklist identifies the Sections, Parts, and Articles of the Reference Specification and the action required or available to the Specifier. The Specifier should review each of the items in the Checklist and make adjustments to the needs of a particular project by including those selected alternatives as mandatory requirements in the Project Specifications.

Checklists do not form a part of ACI Specification Checklists assist the Specifier in selecting and specifying project requirements in the Project Specifications.

Building codes set minimum requirements necessary to protect the public. ACI Specification may stipulate requirements more restrictive than the minimum. The Specifier shall make adjustments to the needs of a particular project by reviewing each of the items in the checklists and including those the Specifier selects as mandatory requirements in the Project Specifications. Orientation that can be met with standard shop equipment.

These standard of reinforcing steel in two-way symmetrical columns shall be tolerances are shown in Fig. Where more restrictive tolerances are required than those shown in the referenced figures, they shall be indi- 1. The effects of tolerances on 1. Drawings must show 2. For bridge design, the Hooks and bends are specified to standardize the fab- AREMA design manual and the AASHTO bridge specifica- rication procedure and to limit the concrete stresses in the tions require a minimum spacing equal to 1.

See Table 1 and Fig. For buildings, Splice arrangements shall be shown. For eter at mechanical splices and for access to welding. Special cast-in-place bridges, required clear space is the larger of 1. Other tables in the supporting reference data section simi- 2. The slope of the in- in a position to determine whether bars should be permitted clined portion providing the offset shall not exceed one in to be placed in more than a single layer.

These types include open stirrups and closed stirrups from the point of the bend. For practical purposes, three or stirrup-ties Fig. Stirrups are most closely spaced ties are usually used, one of which may be often fabricated from reinforcing bars, but may also be fab- part of the regularly spaced ties, plus two extra ties.

General ricated from welded-wire fabric. Table 1. Where stirrup support bars are required, they must 2. In designing the anchorage, allow- bar arrangement is changed at a floor, the bars may extend ance must be made to ensure that the ends of the stirrup hook through, terminate, or require separate dowels.

Reinforcing are fully encased in concrete, as when hooks turn outward into shallow slabs. Vertical closure may consist of overlapped, standard 90 degree end bars from the column below, terminated for any reason, are hooks of one- or two-piece stirrups, or properly spliced pairs of U-stirrups. Where the design requires closed ties for tor- cut off within 3 in. At least one longitudinal bar shall be located inside each tinued column verticals is required for adequate embedment, corner of the stirrups or ties, the diameter of this bar to be and show this information on the structural drawings.

According to ACI M , from bar or tendon curvature shall be anchored adequately. A bundle is defined as a group of parallel bars bun- Minimum diameters to which standard spirals can be dled in contact to act as a unit. Not more than four bars can formed and minimum diameters that are considered collaps- be grouped into one bundle. Butt splices or separate splice ible are shown below for various sizes of spiral bars.

Plain or bars should be used. Bundled bars must be tied, wired, or otherwise fastened to ensure that they remain in position. All bundles of column verticals must be held by additional ties above and below the Spiral bar Minimum outside Minimum outside diameter, in.

Ties smaller than No. Spirals are used primarily for columns, piers, and drilled 2. Continuously wound, re- 2. A previous calcula- structures as tie reinforcement. Such reinforcing steel, some- tion approach, from ACI M also remains ac- times referred to as continuous ties, is usually specified with ceptable. With multiple code-compliant approaches to a large pitch.

Sufficient information shall be be tied together laterally. Standard arrangements of ties for presented on the structural drawings and in the project spec- various numbers of vertical bars are shown in Fig. The Tables in the supporting reference data section give values arrangements of one-piece ties shown in Fig.

Values of tension ld and tension lap splice before erection. Preassembly is preferred only for the com- lengths in the tables are based on the provisions in ACI See Section normalweight concrete with the concrete compressive 2.

With staggered butt splices on large vertical bars in two- The tables use the terminology Cases 1 and 2. Cases 1 and story lengths, practical erection limitations usually require 2, which depend on the type of structural element, concrete that column ties be assembled on free-standing vertical bars. Standard arrangements for two-piece column ties shown in Fig.

Separate tables are included for uncoated and epoxy-coat- They are universally applicable to any splice arrangement re- ed bars. If access to the interior of a column or a ACI M for zinc-coated galvanized bars and they should be treated as uncoated bars.

ACI 1. The maximum spacings permitted are tural drawings. This information can be shown by dimen- shown in a table in the supporting reference data section. In beams or girders, in the floor system, and the arrangement shall be shown.

Splices where resist tension, but the hook may not be considered in deter- the critical design stress is tensile should be avoided by the mining the embedment provided for compression. Lapped bars may be either in contact Separate splice bars dowels are necessary for splicing or separated. Bars to be spliced by noncontact lap splices in layed, or between various units of structures.

Except for spe- flexural members shall not be spaced transversely more than cial cases, separate splice bars dowels should be the same the smaller of one-fifth the length of lap and 6 in. Lap splices for bars larger length, as measured between outermost cross wires of each than No. These bars must extend the ing the lap splice length equal to one spacing of cross wires minimum distance required for lap splices. For the floor or other member transmitting the additional load to No.

Where the top ends of column bars are less than used. Special preparation of the ends of the vertical bars is 6 ft mm above the top of footings or pedestals, the usually required for butt splices. Where a mechanical splice bars should extend into the footings or pedestals. Normally, is used, both ends of the bar can be either square cut, flame dowels will be used only if specifically noted on structural cut, or standard shear cut, depending on the type of splice drawings.

Field propriate lap splice length for the bars in the column above. All welding This applies regardless of differences in bar sizes. For columns, the arrangement of bars at a lap splice is shown in Fig. It should be noted that the amount of offset 2. Column verticals to be lap spliced in square or rect- signing the corner joint of a rigid frame.

All main reinforcing angular columns, where column size does not change, are usu- steel that passes through the joint shall be free of any kinks ally shop offset bent into the column above, unless otherwise or discontinuous bending. If a mechanical or welded splice is to be quired for dowels of a certain size, the size of dowel should used, a physical description must be provided.

Tension in the be decreased and the number of dowels increased to give an equivalent area. In areas strength. Typical details are shown in Fig. Careful selection of member size and reinforcing show closed stirrups, these stirrups may be closed by two- steel arrangement will help to avoid difficulties in the place- piece stirrups using overlapping standard 90 degree end ment of the reinforcement and concrete. At least one longitudinal bar must be located at and to familiarize the detailer with the seismic reinforcing each corner of the section, the size of this bar to be at least steel details.

Much information can be shown by schematic equal to the diameter of the stirrup but not less than a No. These special seismic details are, in principle, applicable to It should be noted that the use of 90 degree hooks and flexural frame members and frame members subjected to lap splices in closed stirrups is not considered effective in sit- both bending and axial load in regions of high seismic risk.

Tests Reference 1 have shown premature failure layouts carefully in three dimensions and give the detailer the caused by spalling of the concrete covering and consequent proper information. This examination will show congestion at loss of anchorage in the 90 degree hooks and lap splices in beam-column joints of beam, column, and hoop reinforce- these situations see Fig. Large scale drawings, models, or mock-ups of the joint 2. Conti- placed. Continuity of selected flexural frames and boundary members of walls must be capable of reinforcement is achieved by making bars continuous or pro- developing plastic hinging and continuing to resist loads af- viding Class A tension lap splices and terminating bars with ter yielding of the reinforcing steel without crushing or brit- standard hooks at noncontinuous supports.

Certain propor- tle failure of the concrete. To develop this ductility, concrete tions of top and bottom flexural reinforcement in perimeter in these members, including the joints, shall be confined by beams shall be made continuous around the structure and transverse reinforcement consisting of rectangular or circu- confined with closed stirrups.

See ACI 7. For 2. Seismic per- tice. Regions of high earthquake risk correspond to Zones 3 and 4, regions of moderate earthquake risk to Zone 2, and see Chapter 5. A rectan- inforcement for beams. For beams framing into two opposite gular hoop is closed by overlapping degree hooks hav- sides of a column, these bars shall extend through the column ing tail extensions of six bar diameters 3 in.

At other locations in the beam, the positive of the minimum column dimension and 4 in. ACI M steel, cut-off points, and length and location of splices to sat- provisions regulate the size and spacing of the hoops.

Out- isfy these multiple code requirements. Bottom bars shall not be spliced at the columns because Column verticals can be spliced by lap splices, mechanical of possible reversal of beam stresses. ACI M requires that me- Where beams frame into only one side of a column, as at chanical splices or welded splices shall be staggered at least exterior columns, top and bottom beam reinforcing steel 24 in. Offsets of must have a 90 degree hook that extends to the far face of the longitudinal reinforcement is not recommended within the confined region core and bends into the joint.

Length lo shall indicate location and hoop spacing requirements on shall not be less than one-sixth of the clear span height of both sides of the sections where the inelastic yielding can oc- the member, maximum cross-sectional dimension of the cur. Hoop spacing requirements are shown in Fig. Because walls may or may not the beam shall be equal to or greater than one-third the neg- be designed as part of the primary lateral-load resisting sys- ative moment strength.

This term is indirectly defined in ACI The coating process adds time to and diaphragms and reference to typical details see Fig.

Replacement reinforcing steel or The vertical and horizontal reinforcement shall be placed additional reinforcement to correct oversights may not be in at least two curtains if the in-plane factored shear force ex- readily available. The reinforcement ratio in vey specific complete instructions in the project specifica- each direction shall be equal to or greater than 0.

When the compressive force in a boundary member ex- 2. Mechanical splices—Specify requirements for repair of ing until the compressive force is less than 0. Trans- damaged coating after installation of mechanical splices.

Welded splices—Specify any desired or more stringent be fully developed within the confined cores of boundary requirements for preparation or welding, such as removal of members.

Field bending of coated bars partially embedded in con- crease in balancing compressive stresses and shear. If the joint is confined by operations. Cutting of coated bars in the field—This practice is not amounts of transverse reinforcement can be used. These requirements 5. Limits on coating damage—Specify limits on permissi- can often be shown by typical details see Fig. On projects where uncoated and coated times slab or drop panel thickness on opposite faces of the bars are used, to avoid confusion, be precise in identifying column.

It is seldom sufficient to call umns or 1. Reinforcing bars projecting into the element must be identi- See Fig. To meet ACI M , the re- not less than one-third of the total column strip top reinforce- inforcing bars that are to be epoxy-coated shall conform to ment at the support. A minimum of one-half of all bottom re- the requirements of ACI 3.

Suitable coatings steel 2. Bar supports should be made of dielectric material or wire bar supports should be coated with 2. Structural drawings for structures or elements of concrete, for a minimum distance of 2 in. Re- all of the essential information noted previously for uncoated inforcing bars used as support bars should be epoxy-coated. S1 and S2 concrete. S2 should be specified when fab- rication after galvanization includes only bending. Class 1 3. The plan nor- should be permitted in close proximity to galvanized reinforc- mally is drawn in the upper left corner of the sheet, with the ing bars except as part of a cathodic protection system.

Bars that require special finished bend diam- upper right corner of the drawing. A figure in the supporting eters usually smaller bar sizes for stirrups and ties should reference data section presents a recommended layout. Maintenance of identification to the point of An arrow indicating the direction of North should be shipment during the galvanizing process is the responsibility placed beside every plan view.

Regular tags plus metal tags should be at- 3. The regular tag is often con- breviations for placing drawings are shown in the supporting sumed in the galvanizing process, leaving the metal tag for reference data section.

Zinc-coated galvanized bars are Where unusual details or conditions require use of other identified with a suffix G and a note stating that all bars special symbols or abbreviations, the drawings must pro- marked as such are to be zinc-coated galvanized.

Gal- commonly referred to as a schedule. A schedule is a compact vanized bars must not be coupled to uncoated bars. Zinc- summary of all the bars complete with the number of pieces, coated tie wire or nonmetallic coated tie wire should be used. Although these schedules usually include the made of dielectric material. Epoxy-coated reinforcing bars necessary for the placement and fabrication of the material. The designa- schedules, material lists, and bending details. Secure and tie rebar connections.

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