Construction/Methods of SP, ACI Detailing Manual. ASTM International. Here you can find aci sp aci detailing manual pdf shared files . ACI Details and Detailing of Concrete Reinforcement (ACI ) -1 MANUAL OF CONCRETE PRACTICE Chapter 8—Glossary, p. AC1 DETAILING MANUAL Including: Details and Detailing of Concrete Reinforcement (AC) Manual of Structural and Placing.
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tion presented here is a collection of notes derived from ACI. (M); ACI R; AREMA Manual for Railway Engi- neering, Chapter 8, “Concrete Structures. The ACI Code ACI for modifications of some of the This Practical Design and Detailing Manual intends to outline practice of. ACI Reinforcement Detailing Manual SP - Ebook download as PDF File .pdf) or read book online. Manual de la ACI para detallar estructuras de.
Reinforcing steel for larger structures is sometimes de- tailed, fabricated, and delivered by units, for example, foot- ings, abutments,piers, and girders. The tables use the terminology Cases 1and 2. Submits placing drawings, if required by the project is its own identification. All bundles of column verticalsmust be held by additionalties above and below the end-bearing mechanical splices and any short splice bars added for tension should be tied as part of the bundle within the limitationof the numberof bars in a bundle. This applies regardless of differences in bar sizes. 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.
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. They can be tion G is appropriate for galvanized reinforcing bars. The contract documents steel. The same designations should be used ings. Bending details can be shown on a separate drawing in- The described marking systems identify individual, rein- stead of on the placing drawings.
Reinforcing bars 3. Only drawings, the fabricator takes the following steps: Prepares placing drawings including bending details ; proper bars for each member. The straight bar size and length 2. Submits placing drawings, if required by the project is its own identification. Prepares bar lists bills of materials ; evation, or section, or can be listed in a schedule.
It is 4. Fabricates reinforcing steel; acceptable practice to detail footings, columns, beams, and 5. Provides coated bars if specified; slabs in schedules. There is no standard format for schedules. Provides bar supports per customer requirements; and They take the place of a drawing, such as a beam elevation, 7. Tags, bundles, and delivers the fabricated reinforcing and must clearly indicate to the placer exactly where and bars to the job site.
It should be noted that the general term fabricator, as used 3. In this regard, it is actually instructions on the contract documents. They also serve as ble building code for information to use in preparing placing the basis for preparing bar lists. Bending details reinforcing steel is detailed, fabricated, and delivered by may be separate or incorporated in the schedule. The detailer units, which generally consist of building components, such must show number, mark, and size of members; number, size, as footings, walls, columns, each floor, and roof.
A separate and length of straight bars; number, size, mark, and length of placing drawing and bar list are usually made for each com- bent bars and stirrups; spacing of stirrups; offsets of bars; lap ponent.
For small structures, all reinforcing steel can be han- splices; bar supports; and any other special information nec- dled as one unit. For large projects, the contractor may desire essary for the proper fabrication and placement of the rein- a unit, such as a single floor, to be divided to correspond with forcing steel.
Such arrangements, between the Among the special items that must be noted are: Overall length of bar; before the detailing is begun. All sections should be kept as 2. Height of hook where such dimensions are controlling; large as practical because it is more economical to detail and 3.
Lap splice lengths; fabricate for large units, especially where there is apt to be a 4. Offset dimensions, if any; and duplication of bars. Location of bar with respect to supporting members 3. Where possible, the same designa- 3. When members alike on the structural The schedule and bending details for slabs are similar to drawings are slightly different on the placing drawings, a those for beams.
If some of the beams marked 2B3 on the structural and reinforcing steel is shown for only one panel of each drawing actually differ from the others, the placing drawing kind. In skewed panels, such as for the quadrant of a circle, would show some of the beams as 2B3 and the others as the bars are fanned out so that they are placed at the required 2B3A. In reinforced-concrete joist floors, there can be so spacing at a specific location, usually at the midspan. Addi- many variations from the basic joists shown on the structural tional bars around openings, if required, must be shown.
Standardized marks are sometimes pretation to the placer. The detailer must show the quantity, used for bars occurring in the same relative position in cul- size, and length or mark of all bars, including dowels, prin- verts. The detailer must also include Any system of letters and numerals is acceptable.
The detailer must clearly show length and by the mark, where the bar is placed in the structure. Schedules are sometimes used for piers, small with the reinforcing steel in the element that is placed first. Highway structural They must be ordered with the element to be available for drawings usually include, when detailed completely, a type placement at the proper time. These drawings are used by ports specified in the contract documents, including quanti- the fabricator to prepare shop bar lists.
These layouts can be shown shown clearly. The contractor should not have to compute on the placing drawing or given by reference to the CRSI Man- any needed dimensions. Drawings must show the dimen- ual of Standard Practice.
Support bars, when required, must be sions of concrete protection for all reinforcing steel. For ex- shown clearly and identified on the placing drawings. Where Unlike the customary practice in the field of reinforced- separate placing drawings are prepared, structural dimen- concrete buildings, many state highway departments prepare sions may be omitted following the same practice as for a combination structural and placing drawing. The combina- buildings.
The placer uses size, spacing, splices, and location of the coated and uncoat- the combination drawing to place the reinforcing bars. High- ed bars in the structure. The bar schedule combined draw- way departments that do not use combination drawings fol- ing must show the number of pieces, size, length, mark of low the procedures of Section 3.
This station identification or bridge number abutments, piers, and girders. The bar list is then similarly must be shown on all bundle tags and shipping papers to fa- subdivided. If the structure is sufficiently large, a separate cilitate proper distribution of reinforcing bars on delivery.
For small, simple structures such as culverts, slab bridges, Reinforcing bars for foundations, piers, abutments, wing manholes, and catch basins, a station number in addition to walls, and slabs are usually shown on plan, section, or eleva- the title description of the structure is sufficient identifica- tion views.
Reinforcing steel can be shown in the simplest tion without dividing the structure into smaller units by fur- and clearest manner, however, the bar list must be a com- ther marking. Larger structures, such as reinforced-concrete deck gird- To be certain that all of the reinforcing steel is properly ers, I-beam bridges, continuous-type bridges, and arches, placed or positioned in a unit, a cross section is frequently re- consist of small units that together make up a complete struc- quired in addition to the plan and elevation of the unit where ture.
These units are referred to as end bents, intermediate the bars are shown. The used widely as a means of securely holding reinforcing steel construction units of unusually long culverts with more than in proper position while the concrete is being placed. Plastic one design of barrel, for varying load conditions or, where coated or stainless legs can be specified to avoid possible construction joints are required across the barrel, can be iden- rusting at points of exposure.
Precast concrete blocks are tified by section numbers. Schedules of reinforcing bars are used in some states, particularly in the western United States. Support bars, when furnished, should be shown in lots as required. For highway structures, both straight and bent bars are given Where an exposed concrete surface is to receive special an individual mark. The standard hooks Table 1 were devel- the finished surface appearance.
The detailer should identify the specified types and was recognized as well. In the Table, the extra length of bar show locations where each is to be used. It is standard practice in the industry to show all bar di- Where the physical conditions of the job are such that ei- mensions as out-to-out and consider the bar lengths as the ther J, A, G, or H of the hook is a controlling dimension, it sum of all detailed dimensions, including Hooks A and G must be so noted on the drawings, schedules, and bar lists.
Controls are anchorage. The most common is to use one of the hooks established by specifying the minimum inside radius or in- shown in Table 1. Types Sl to S6 in Fig. In detailing the anchorage, multiple of the nominal diameter of the bar db. The ratio of diameter of bend to diameter of bar is not a constant because care must be taken that the ends of stirrup hooks that are it has been found by experience that this ratio must be larger turned outward into shallow slabs have adequate cover.
If as the bar size increases. A 6db 6db 19, 22, 25 chart of such standard bar bends is shown in Fig. For straight portions of the bar, the distance is measured to the theoretical intersection of the outside edge line extended to the outside edge line of the adjacent straight portion, or to The inside diameter of bends of welded-wire fabric plain the point of tangency to a curve, from which point the length or deformed for stirrups and ties, as specified by ACI M , shall not be less than 4db for deformed wire larger of the latter is tabulated, as in Types 10 and 11 in Fig.
Hirsch Javed B. Malik WilliamG Sebastian,Jr. David F. Horton DennisL. Hunter MiltonR. Sees Avanti C. Locationsofcutoff pointsandbends, amountsof steel,etc. Wires and welded wire fabric Mathematicaltables and formulas Common symbolsand abbreviations Flach Anthony L. Murray Lount Miguel R.
Casias Edward S. Hoffman Peter Meza Robert E. Doyle David W. Johnston Vasant C. Mistry Gustav G. Erlemann Robert W. Johnson Roy H. Reiterman Gerald E. Goettsche Harry B. Sees Douglas D. It is divided into three parts: It dejines the responsi- bilities of both the ME and detailer It then establishes certain standards of practicefor both the structural and placing drawings.
I-General 2. I-General 5. I-Use of computers in detailing 6. I-Referenced standards 9. Copyright O , 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,or recording for sound or visual reproduc- tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtainedfrom the copyright proprietors.
In thepast, duringthe courseof developingplacingdrawings, the detailer often suggested solutions in areas where the details were incomplete and where the reinforcing steel appeared to have constructibility problems. Unfortunately, many problems do not surface during the de- tailing phase but rather occur during construction. As the complexity of design and construction increases, it is imperativethat both the AIE and detailer understand their responsibilities clearly.
This standardpresents values in inch-pound and SI units. Hard metric values are usually not exact equivalents; there- fore, each system is to be used independently of the other.
Combining inch-pound and hard metric values can result in nonconformance with the standard. Soft metric values are exact equivalents, so combining inch-poundand soft metric values conformsto the standard.
The structural drawings and the project specifications form a part of the contractdocuments. Structural drawingsmust contain an ad- equate set of notes and all other essential information in a form that can be quickly and correctly interpreted.
These drawings must convey definite instructions and show rein- forcing bars and welded wire fabric. Structural and placing drawings may be combined. Instead, this informa- tion shall be interpreted by the AE and shown in the form of specific design details or notes for the detailer to follow. Where omissions,ambiguities, or incompatibilities are dis- covered, additional information, clarifications, or correc- tions shall be requested by the detailer and provided by the AIE.
Anchorage length of reinforcing steel and location and length of lap splices; and 2. Type and location of mechanical and welded splices of reinforcing steel. Other media providing improved reproducibility or durability, such as microfilm, electronic files, ink, tracing cloth, or polyester film, can also be used. All sheetsin any one setof drawingsshouldbe the same size. There are two weil-recognizedsets of standardsizes. Border lines are inside these dimensions. Requirements for placing drawings are in Part B, addressed to the detailer.
Drawings that can be enlarged or reduced in reproduction should show a graphic scale, as well as a descriptive one, to aid the user. Structural drawings and project specificationsshall also show concrete dimensions,anchoragelength of reinforcing steel and location and length of lap splices, type and location of mechanical and welded splices of reinforcing steel, concrete cover for the reinforcing steel, requiredjoints, and any other informa- tion needed for the preparation of the placing drawings.
In addition to these requirements, structural draw- ings of beams, girders, and columns must also show the information presented below. Show sections for beam-column joints, where necessary.
In continuous beams, the number and spacing of top bars to be placed in T-beam flanges slabs for crack control shall be shown, if so required by the design. Method of splicing shall always be defined clearly, showing arrangement of splices, type lap, mechani- cal or welded , length if lap splice , and stagger.
Orientation of reinforcing steel in two-way symmetricalcolumns shall be shown when reinforcing steel is not two-way symmetrical. Drawings must show the dimensions of concrete protection for all reinforcing steel. The list of bars must show the number of pieces, size, length, mark of bars, and bending details of all bent bars. The list of welded wire fabric must show the mark, style, width, length, and number of pieces. Reinforcing steel for larger structures is sometimes de- tailed, fabricated, and delivered by units, for example, foot- ings, abutments,piers, and girders.
The reinforcing steel list may be subdivided similarly. If the structure is sufficiently large, a separatedrawing and reinforcing steel list is usually made for each unit. Reinforcing steel for foundations, piers, abutments, wing walls, and slabs are usually shown on a plan, section, or ele- vation view on the drawings.
Cross sectionsmust be provid- ed for clarification where necessary. The reinforcing steel list is a complete summary of materials required. All bars should appear at least once in a plan or elevation view and in a sectional view, or both.
For reference data on reinforcing bars and welded wire fabric from industry sources, refer to the Supporting Refer- ence Data section of AC1 SP This section includes spe- cific informationon applicable ASTM specifications,coated reinforcing bars, common styles and design data for welded wire fabric, and reinforcing bar supports.
Concrete Structures and Foundations;? Reinforcing steel for structures designed under the provisions of AC1 , AC1 , and other similar documents can generally incorporate the direction given in this standard unless otherwise prohib- ited by the provisions of the respective related documents.
Practicallimitationsof equipmentand production efficien- cy haveledto the establishmentof certainfabricationtolerances that can be met with standard shop equipment. These standard tolerancesare shown in Fig. Where more restrictive tolerances are required than those shown in the referenced figures, they shall be indi- cated in the contract documents. See Table 1 and Fig.
The term? Subject to requirements of AC1 M , Section 7. For cast-in-placebridges, required clear spaceis the larger of 1. Other tables in the supportingreference data section simi- larly give the same information for beams designed under the provisions of the AASHTO bridge specifications.
These tables are provided for the use of the AIE;the detailer is not in a position to determinewhether bars should be permitted to be placed in more than a single layer. These types include open stirrups and closed stirrups or stirrup-ties Fig. Stirrups are most often fabricated from reinforcing bars, but may also be fab- ricated from welded wire fabric.
There are various permissible methods of anchorage,but the most common is to use one of the standard stirrup-tie types as shown inFig. In designingthe anchorage, allow- ance must be made to ensurethat the ends of the stirruphook are fully encased in concrete, as when hooks turn outward into shallow slabs.
Where the design requires closed stirrup-ties for shear,the closure may consist of overlapped, standard 90 degree end hooks of one- or two-piece stirrups,or properly spliced pairs of U-stirrups. Where the design requires closed ties for tor- sion, the closure may consist of overlapped,standard de- gree hooks of one- or two-pieceties enclosinga longitudinal bar. At least one longitudinalbar shall be located inside each corner of the stirrups or ties, the diameter of this bar to be equal to at least the diameter of the stirrup No.
Ties provided to resist radial forces resulting from bar or tendon curvature shall be anchored adequately. Splice arrangements shall be shown. For butt-spliced sys- tems, an allowancemust be included for an increase in diam- eter at mechanical splices and for accessto welding.
Special end preparation required for bars must be shown or speci- fied. Where the reinforcing steel area required above is dif- ferent from that in the column below, the structural drawings must clearly show the extension required if any of all rein- forcing bars above and below the floor level see also Sec- tion 2.
The slope of the in- clined portion providing the offset shall not exceed one in six. See Fig. Where column verticals are offset bent, additional ties are required and shall be placed not more than 6 in. For practical purposes, three closely spaced ties are usually used, one of which may be part of the regularly spaced ties, plus two extra ties.
General arrangements of vertical bars and all tie requirements shall be established by the structural drawings. In addition to showing size and regular spacingof column ties, the AE shall also show any additional ties required for special conditions, such as splices and offset bends.
Reinforcing steel at least equal in area to that in the column above must be extendedfrom the column below to lap bars above by the requiredlap length or butt splices must be provided. Vertical bars from the column below, terminated for any reason, are cut off within 3 in. According to AC M , the clear spacing between spiral turns shall not exceed 3 in. If necessary to splice a spiral, it shall be done by a lap splice of 48db or by welding. Minimum diameters to which standard spirals can be formed and minimum diameters that are consideredcollaps- ible are shown below forvarious sizes of spiral bars.
Plain or deformed bars or wire can be used to manufacture spirals. Spirals are used primarily for columns, piers, and drilled caissons, but are also used in piles. Spiralbar diameter,in. Such reinforcing steel, some- times referred to as continuousties, is usually specified with a large pitch.
Standard arrangements of ties for various numbers of vertical bars are shown in Fig. The A E may also specify welded wire fabric with an equivalent area of reinforcing steel for column ties. The arrangements of one-piece ties shown in Fig. Reassembly is preferred only for the com- mon designsemploying one-story-lengthvertical bars all lap spliced at or near one point above the floor line. See Section 2. With staggered butt splices on large vertical bars in two- story lengths, practical erection limitations usually require that column ties be assembled on free-standing vertical bars.
Standard arrangements for two-piece column ties shown in Fig. If access to the interior of a column or a pier is necessary, or if the A E prefers, some other pattern of ties may be substituted, provided that the tie arrangement meets AC M requirements. The spacing of ties depends on the sizes of vertical bars, columns, and of ties. The maximum spacings permitted are shown in a table in the supportingreference data section. If the design requires lateral reinforcement in the column between the top of the main spiral and the floor level above, it may be provided by a stub spiral short section of spiral or circular column ties to permit placing of the reinforcing steel in the floor system, and the arrangement shall be shown.
A bundle is defined as a group of parallel bars bun- dled in contact to act as a unit. Not more than four bars can be grouped into one bundle. Butt splices or separate splice bars should be used. Bundled bars must be tied, wired, or otherwise fastened to ensure that they remain in position. All bundles of column verticalsmust be held by additionalties above and below the end-bearing mechanical splices and any short splice bars added for tension should be tied as part of the bundle within the limitationof the numberof bars in a bundle.
Bundled bars shallbe enclosedwithin ties. Ties smallerthan No. Design and detail infor- 2. A previous calcula- tion approach,from AC M also remains ac- ceptable. Sufficientinformationshall be presented on the structural drawings and in the project spec- ificationsto allowdetailing of bars at splicesand embedment locations without referencing back to the code. Tables in the supporting reference data section give values of tension developmentlengths and tension lap splice lengths of straight bars.
Values of tension Ld and tension lap splice lengthsin the tablesarebased on the provisionsin AC1 All tabulated data are for Grade 60 reinforcing bars in normalweight concrete with the concrete compressive strength,f: The tables use the terminology Cases 1and 2. Cases 1and 2, which depend on the type of structural element, concrete cover, and the center-to-center spacing of the bars, are also defined in the tables.
Separate tables are included for uncoated and epoxy-coat- ed bars. There are no special development requirements in AC M for zinc-coated galvanized bars and they should be treated as uncoated bars. For lightweight aggre- gate concrete, the values in the tables would have to be mod- ified by the applicable factor AC1 AC1 1. This information can be shown by dimen- sioning cut-off locations and including tables of applicable lap splice lengths. In beams or girders, splices should preferably be made where the stress in the bar is minimum, that is, at the point of inflection.
Lapped bars may be either in contact or separated. Bars to be spliced by noncontact lap splicesin flexural members shall not be spaced transversely more than the smaller of one-fifththe length of lap and 6 in. Lap splicesare not per- mitted for No. Lap splices for bars larger than No. At column bar splice locations, sufficientbars or dowels from the lower columns must extend into the upper column to provide not less than the cross-sectional area of the re- quired bars in the upper column.
These bars must extend the minimum distance required for lap splices. Where the top ends of columnbars are less than 6 ft mm above the top of footings or pedestals, the bars should extend into the footings or pedestals. Normally, dowels will be used only if specifically noted on structural drawings. The AE should also be aware that it is a standard practice in the industry when detailingcolumn verticals to use the ap- propriate lap splice length for the bars in the column above.
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 of the bars is greater for rectangular columns than for round columns. Where the depth of the footing, or footing and pedestal combined,is less than the minimum length of embedment re- quired for dowels of a certain size, the size of dowel should be decreased and the number of dowels increasedto give an equivalent area.
This should also be shown on the structural drawings. Hooks at the ends of the bars can be desirable to resist tension, but the hook may not be consideredin deter- mining the embedment provided for compression. Separate splice bars dowels are necessary for splicing columnbars where the columnsectionchanges3 in.
Lap splices for deformed welded wire fabric shall be shown by the AB. WhenA, provided A, required 2 2, only the requirement of 1. For No. Special preparation of the ends of the vertical bars is usually required for butt splices. Where a mechanical splice is used, both ends of the bar can be either square cut, flame cut, or standard shear cut, depending on the type of splice used.
Where bars are welded, the most common practiceis toprovide a square-cutend at the top of the lowerbar and a double-beveled end on the bottom of the upper bar. Field preparation of ends by flame cutting is satisfactory.
All welding of reinforcingbars shall conformto AWS D1. All main reinforcing steel that passes through the joint shall be free of any kinks or discontinuousbending. The center of radius of the bend must be kept within thejoint. Thispoint is important in splic- ing the top bars from the girder to the outside bars in the col- umn.
If a mechanical or welded splice is to be used, a physical description must be provided. Tensionin the concrete surrounding the reinforcing steel where the steel changes direction must be considered.
In areas wherethe applicablebuilding coderequiresearthquake-resistant design, standard practice requires adequateanchorageof all horizontal bars. Walls with loads that open comer intersectionsmust be re- inforced differently than walls with loads that close such in- tersections.
Typical details are shown in Fig. Precautions to restrain radial tension are similarto those for rigid frame comers. At least one longitudinal bar must be located at each comer of the section, the size of this bar to be at least equal to the diameter of the stirrup but not less than a No. These details shall be shown by the AIE.
It should be noted that the use of 90 degree hooks and lap splicesin closed stirrupsis not consideredeffective in sit- uations where the member is subjected to high torsional stress.
Tests Reference 1 have shown premature failure caused by spalling of the concrete covering and consequent loss of anchorage in the 90 degree hooks and lap splices in these situations see Fig. Conti- nuity is required in cast-in-place construction for joists, beams, and two-way slabs.
Continuity of selected flexural reinforcementis achievedby making bars continuous or pro- viding Class A tension lap splices and terminating bars with standard hooks at noncontinuous supports. Certain propor- tions of top and bottom flexural reinforcement in perimeter beams shall be made continuous around the structure and confined with closed stirrups.
Specifications for the use of reinforcing steel supports usually are based on establishedindustry prac- tice. Careful selection of member size and reinforcing steel arrangementwill help to avoid difficulties in the place- ment of the reinforcement and concrete. Much information can be shown by schematic diagrams as shown in Fig. These special seismic details are, in principle, applicable to flexural frame members and frame members subjected to both bending and axial load in regions of high seismic risk.
It is important for the AE to examine the reinforcing steel layouts carefully in three dimensions and give the detailerthe proper information. This examinationwill show congestionat beam-column joints of beam, column, and hoop reinforce- ment.
Large scale drawings, models, or mock-ups of thejoint details, such as those shown in Fig. When subjectedto reversals of lateral overloads, joints in frames and boundary members of walls must be capable of developing plastic hinging and continuing to resist loads af- ter yielding of the reinforcing steel without crushing or brit- tle failure of the concrete.
To develop this ductility, concrete in these members, including the joints, shall be confined by transverse reinforcement consisting of rectangular or circu- lar hoops see Fig. For lightweight aggregate concrete,f: Test results indicate that welded wire fabric hoops designed according to AC1 M requirements are effective in confining the concrete in the joints Reference 2.
Regions of high earthquake risk correspond to Zones 3 and 4, regions of moderate earthquake risk to Zone 2, and low or no risk in Zone 1 in the Uniform Building Code.
For beams framing into two opposite sides of a column,these bars shall extend through the column core at least twice the beam depth without splices see Fig. At joint faces, the positive moment strength of the beam shall be equal to or greater than one-half the negative mo- ment strength.
At other locations in the beam, the positive and negative moment strengths shall be equal to or greater than one-fourth the negative moment strength at the face of either joint.
The AIE shall indicate quantities of reinforcing steel, cut-off points, and length and location of splices to sat- isfy these multiple code requirements. Continuous top bars must be spliced near the center of a span in frames where moments are usually minimum and gravity load moments do not usually produce tensile stress- es.
Bottom bars shall not be spliced at the columns because of possible reversal of beam stresses. At beam-column joints, the AE shall indicate where and how the bars, straight or hooked, are to be terminated.
Where beams frame into only one side of a column, as at exterior columns, top and bottom beam reinforcing steel must have a 90degreehook that extendsto the far face of the confined region core and bends into the joint.
Hoops shall be provided in frame members over twice the member depth from the faces of the supports and toward midspan. Hoop spacingrequirementsare shown in Fig. At other locations in the beam, the positive and negative moment strengths shall be equal to or greater than one-fifth the negative moment strength at the face of eitherjoint.
Stirrups shall be provided for a minimum length of twice the member depth from the supportat an initial spacing of 2 in. A rectan- gular hoop is closed by overlapping degree hooks hav- ing tail extensions of six bar diameters 3 in. Crossties of the same bar size and spacing of hoops may be used, but eachend of the crosstie shall engagea peripheral vertical bar.
Hoops at a maximum spacing not exceeding one-quarter of the minimum column dimension and 4 in. AC1 M provisions regulate the size and spacing of the hoops. Out- side this region, hoops shall be as required for nonseismic columns,includingrequirementsfor shear, and spacingshall not exceed six times the diameter of the longitudinal column bars or 6 in mm. Columnverticals canbe splicedby lap splices,mechanical splices, or welded splices.
Lap splices are permitted only within the center half of the column length and shall be de- signedas tension splices. AC M requires that me- chanical splices or welded splices shall be staggeredat least 24in.
Offsets of longitudinal reinforcement is not recommended within the joint. Length 1, shall not be less than one-sixth of the clear span height of the member, maximum cross-sectional dimension of the member, and 18 in. Usually this task can be accomplishedby identifying structuralwalls and diaphragms and reference to typical details see Fig. The reinforcement ratio in each direction shall be equal to or greater than 0. When the compressive force in a boundary member ex- ceeds 0.
This term is indirectly defined in AC1 Trans- verse reinforcementfrom wall and diaphragmmembers shall be fully developed within the confined cores of boundary members.
Trans- verse hoop reinforcement, as for high-risk seismic columns, shall be provided in the joints. If the joint is confined by structural members meeting special requirements, lesser amounts of transverse reinforcement can be used.
These requirements can oftenbe shownby typical details see Fig. The AE shall show the reinforcing steel to be concentratedin this critical width. Continuouscolumn strip bottom reinforcing steel shall be not less than one-third of the totalcolumn striptop reinforce- ment at the support. A minimumof one-half of all bottom re- inforcementat midspan shall be continuousand developed at the faces of the supports.
All top and bottom reinforcing steel shall be developed at discontinuousedges. Structural drawings for structures or elements of structures that contain coated reinforcing steel shall include all of the essentialinformationnoted previouslyfor uncoated reinforcement.
The coating process adds time to the normal delivery cycle. Replacement reinforcing steel or additional reinforcement to correct oversights may not be readily available.
Mechanical splices-Specify requirements for repair of damaged coating after installation of mechanical splices. Welded splices-Specify any desired or more stringent requirements for preparation or welding, such as removal of coating, beyond those contained in AWS D1.
Field bending of coated bars partially embeddedin con- crete-If permitted by the AE,specify requirements for re- pair of damaged coating after completion of bending operations. Limits on coating damage-Specify limits on permissi- ble coating damage caused by handling, shipment, and plac- ing operations, and when required, the repair of damaged coating. On projects where uncoated and coated bars are used, to avoid confusion, be precise in identifying those bars that are to be coated.
It is seldom sufficient to call for coated reinforcingbars in an element with a generalnote. Reinforcing bars projecting into the element must be identi- fied if they are to be coated. To meet AC1 M , the re- inforcing bars that are to be epoxy-coated shall conform to the requirements of AC1 3. Suitable coatings are nylon, epoxy, or vinyl. Bar supports should be made of dielectricmaterial or wirebar supportsshouldbe coated with dielectric material, such as epoxy or vinyl compatible with concrete, for a minimum distance of 2 in.
Re- inforcing bars used as support bars should be epoxy-coated. To meet AC1 M requirements,the reinforcingbars that are to be zinc- coated galvanized shall conform to AC1 3.
SupplementaryRequirement S1 requires sheared ends to be coated with a zinc-richformulation;when bars are fabricated after galvanizing, S2 requires damaged coating to be re- 2.
S1 and S2 should be specified when fabrication after galvanization in- cludescuttingand bending. S2shouldbe specifiedwhen fab- rication after galvanization includes only bending. Class 1 3. Bars that require special finished bend diam- eters usually smaller bar sizes for stirrups and ties should be identified.