This specification covers the materials, fabrication, delivery, and installation of steel reinforcing bars and welded wire reinforcement for cast-in-place reinforced concrete construction. All reinforcement shall conform to the requirements of ACI CODE-318-19(22), Building Code Requirements for Structural Concrete and Commentary, and shall be installed in strict accordance with the Contract Drawings, the Shop Drawings reviewed under this specification, and ACI SPEC-301-16, Specifications for Structural Concrete. Where these documents conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
Reinforcing steel is not a commodity item installed by rote. Its structural function depends entirely on its grade, coating condition, precise placement, adequate cover, and properly developed splices. A bar placed one inch low in a slab, a lap splice too short by six bar diameters, or a tie displaced during concrete vibration can each compromise the structural integrity of the element. This specification establishes requirements that protect the structural function of the reinforcement from mill certification through concrete placement, and it shall be read in conjunction with Cast In Place Concrete for requirements governing the concrete itself.
Reinforcing steel work under this specification includes: deformed reinforcing bars (straight, bent, and headed), plain bars used as spirals or column ties where permitted, welded wire reinforcement (WWR) in rolls and sheets, mechanical splicing systems (couplers and headed bar terminations), bar supports and chairs, and field welding of reinforcement where permitted by the Contract Documents.
Materials, fabrication, and installation shall comply with the latest adopted edition of the following standards and codes. Where a more recent edition of a referenced standard has been adopted by the Authority Having Jurisdiction since the date of these Contract Documents, the Contractor shall notify the Engineer of Record before proceeding.
| Standard | Title |
|---|---|
| ACI CODE-318-19(22) | Building Code Requirements for Structural Concrete and Commentary |
| ACI SPEC-301-16 | Specifications for Structural Concrete |
| ACI 117-10 | Specification for Tolerances for Concrete Construction and Materials |
| ASTM A615/A615M | Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement |
| ASTM A706/A706M | Standard Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement |
| ASTM A1035/A1035M | Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement |
| ASTM A775/A775M | Standard Specification for Epoxy-Coated Steel Reinforcing Bars |
| ASTM A934/A934M | Standard Specification for Epoxy-Coated Prefabricated Steel Reinforcing Bars |
| ASTM A767/A767M | Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement |
| ASTM A1064/A1064M | Standard Specification for Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete |
| AWS D1.4/D1.4M | Structural Welding Code — Reinforcing Steel |
| ASTM A370 | Standard Test Methods and Definitions for Mechanical Testing of Steel Products |
| CRSI MSP | CRSI Manual of Standard Practice (current edition) |
| CRSI RB4.1 | Supports for Reinforcement Used in Concrete |
| IBC | International Building Code (locally adopted edition) |
Contractor shall submit shop drawings and bar lists for review by the Engineer of Record before any reinforcement is fabricated or delivered to the project site. The shop drawings shall be prepared by a qualified detailer in accordance with the CRSI Manual of Standard Practice and shall show, for every concrete element: bar sizes, grades, coatings, lengths, bends, hook geometry, placement dimensions, bar spacing, concrete cover to each bar face, splice locations and lengths, mechanical coupler types and locations, lap zones, and bar support locations and types.
Bar lists shall be keyed to the shop drawing mark system and shall state, for each bar mark: bar designation, grade, coating, quantity, length, bending details with critical dimensions flagged, and unit and total weight. Bar lists serve as the fabrication order and shall be complete enough that no additional information is required from the Contract Drawings during fabrication.
Certified mill test reports (CMTRs) shall be submitted for every heat of steel used on the project. CMTRs shall show: heat number, bar designation and grade, carbon equivalent (CE) for bars designated for welding, yield strength, tensile strength, elongation, and bend test results. CMTRs shall be submitted before the material they represent is incorporated into the work.
For ASTM A706 bars designated for field welding, the carbon equivalent shall not exceed the maximum specified in ASTM A706. For ASTM A615 bars proposed for welding, chemical analysis shall be submitted and reviewed by the Engineer before welding commences; ACI 318-19 Section 26.6.2 and AWS D1.4 govern the weldability assessment.
Where mechanical splices (couplers, headed bars, or end-bearing splices) are used, Contractor shall submit product data including: coupler designation, bar sizes and grades compatible, performance classification per ACI 318-19 Section 26.6.3 (Type 1 or Type 2), test reports confirming required performance, and manufacturer's installation and torque requirements. Mechanical coupler data shall be submitted before installation of the first coupler.
Where special inspection of reinforcement is required by the locally adopted IBC and the project's Statement of Special Inspections, the Contractor shall coordinate the inspection program with the Special Inspector. Special inspection submittals shall be made in accordance with the Statement of Special Inspections, not this specification section alone.
At project closeout, Contractor shall provide as-built markup drawings indicating all field changes to reinforcement placement, splices, and cover that deviated from the reviewed shop drawings and were accepted by the Engineer of Record. Deviations not documented and accepted shall be treated as nonconformances.
Reinforcing steel fabrication shall be performed by a fabricator regularly engaged in the production of reinforced concrete steel for structural construction. The fabricator shall maintain current CRSI Chapter Certification or equivalent certification from an approved certification program, and shall have in-house bending and cutting equipment capable of producing the required bar sizes without overstress or cracking at bend points.
Reinforcement shall be placed by a contractor experienced in reinforced concrete construction and capable of maintaining the tolerances specified in ACI 117. Workers who make field welds on reinforcing steel shall be qualified welding operators tested and certified in accordance with AWS D1.4 for the processes and positions used on this project. Qualification records shall be available to the Special Inspector on request.
Special inspection of reinforcing steel shall be performed in accordance with IBC Chapter 17, the locally adopted building code, and the project's Statement of Special Inspections. The type and frequency of special inspection shall be as indicated in the Statement of Special Inspections, which takes precedence over any conflicts with this specification. Special inspection shall include, at minimum: verification of bar grade and size against shop drawings, inspection of bar placement, cover, spacing, and lap lengths prior to concrete placement, and observation of mechanical splice installation.
All reinforcing steel work shall be designed, detailed, and placed in accordance with ACI CODE-318-19(22). Where the Engineer of Record has specified a locally adopted edition of ACI 318 that differs from ACI 318-19, the requirements of the locally adopted edition shall govern for code compliance.
ASTM A615 deformed bars are the most widely used reinforcing bars in the United States and are the default specification for most cast-in-place structural concrete work. ASTM A615 is available in Grade 40, Grade 60, Grade 80, and Grade 100, with yield strengths of 40,000 psi, 60,000 psi, 80,000 psi, and 100,000 psi respectively. Grade 60 is the predominant grade in current commercial construction and the default for most elements unless the Contract Drawings specify otherwise.
Grade 80 and Grade 100 bars permit reduced cross-sectional steel area for a given force demand and are used where congestion is a concern or where high-performance concrete design is employed. However, ACI 318-19 places limits on which elements and load combinations permit Grade 80 and Grade 100 bars, and the Contract Drawings shall indicate where higher-strength grades are required.
ASTM A615 bars have no controlled chemistry requirement and are therefore not routinely weldable. Field welding of ASTM A615 bars requires chemical analysis of each heat before welding to establish a preheat requirement per AWS D1.4.
ASTM A706 deformed bars are specified where field welding of reinforcement is anticipated, or where enhanced ductility and predictable yield-to-tensile ratios are required for seismic design. ASTM A706 limits carbon equivalent and alloy chemistry so that bars are weldable in accordance with AWS D1.4 without chemical analysis of individual heats. ASTM A706 is available in Grade 60 and Grade 80.
For seismic force-resisting systems in Seismic Design Categories D, E, and F, ACI 318-19 Chapter 18 requires that longitudinal bars in special moment frames and special structural walls shall be ASTM A706 unless the Engineer of Record has specifically approved ASTM A615 based on project-specific testing. Where the Contract Drawings designate seismic application requirements, ASTM A706 bars shall be used unless the Contract Drawings explicitly permit ASTM A615.
ASTM A1035 deformed bars (Grade 100 and Grade 120) are low-carbon, chromium-alloy bars with significantly higher strength and corrosion resistance than ASTM A615. They are used in congested sections, transfer elements, high-rise columns, and marine or aggressive exposure environments where their inherent corrosion resistance eliminates or reduces the need for coating. ASTM A1035 bars are not routinely weldable; their high strength and unique chemistry require special consideration under AWS D1.4.
The use of ASTM A1035 bars shall be limited to applications specifically designated on the Contract Drawings. ACI 318-19 permits Grade 100 and Grade 120 bars for certain applications with limitations on ductility-sensitive seismic elements. ACI PRC-439.6-19 provides guidance on design using ASTM A1035 bars.
Reinforcing bars shall be furnished in standard ASTM bar designations from No. 3 through No. 18, as indicated on the Contract Drawings and shop drawings. Bar designation numbers correspond to the nominal diameter in eighths of an inch: No. 3 = 3/8 in., No. 4 = 1/2 in., No. 5 = 5/8 in., and so on. Bar sizes larger than No. 11 (1-3/8 in. nominal diameter) require special attention to lap splicing restrictions; ACI 318-19 prohibits lap splices for No. 14 and No. 18 bars except for specific conditions. Substitute bar sizes may be used only with written approval of the Engineer of Record and shall provide equivalent or greater cross-sectional area and equivalent or greater development capacity.
Epoxy-coated reinforcing bars shall conform to ASTM A775/A775M (bars coated in the straight condition and bent after coating) or ASTM A934/A934M (bars coated after bending), as required by the Contract Drawings. The coating type shall match the intended fabrication sequence: where bars must be bent in the field, ASTM A775 bars shall be used. Where bars are to be bent at the fabrication shop before coating, ASTM A934 bars shall be used.
Epoxy-coated bars are specified for elements in direct contact with de-icing salts (parking garage decks, bridge abutments, exterior slabs), for submerged or splash-zone concrete, and for other high-chloride exposure environments. The epoxy coating reduces chloride ion penetration to the bar surface and significantly extends time-to-corrosion in aggressive exposures. Epoxy coating is not a complete substitute for adequate concrete cover; cover requirements for epoxy-coated bars are specified in ACI 318-19 Table 20.6.1 and in Section 7 of this specification.
Epoxy-coated bars shall be handled carefully throughout delivery, storage, bending, placing, and concrete placement to avoid coating damage. Bars shall not be dragged across surfaces or against each other. All coating damage occurring after fabrication — cuts, abrasions, and voids — shall be repaired with an approved patching compound compatible with the coating system before concrete is placed; any unrepaired damage area exceeding the ASTM A775 or ASTM A934 allowable shall be cause for rejection.
Zinc-coated (galvanized) reinforcing bars shall conform to ASTM A767/A767M. Galvanized bars are used where long-term corrosion resistance is required and epoxy coating is not preferred — for example, where bars must remain visually inspectable throughout their life, or where the project owner prefers galvanizing for compatibility with other galvanized components. Galvanized bars shall not be used in conjunction with aluminum embedments without an isolation barrier, because contact between zinc and aluminum in a wet concrete environment creates a galvanic couple that accelerates corrosion of the aluminum.
Stainless steel reinforcing bars (ASTM A955/A955M) may be specified for extremely aggressive environments — marine immersion zones, structures exposed to severe chemical attack, and bridges in high-chloride regions — where neither epoxy coating nor galvanizing provides sufficient service life. Stainless steel bars are significantly more expensive than coated carbon-steel bars; their use shall be limited to elements and zones specifically designated on the Contract Drawings.
Welded wire reinforcement (WWR) shall conform to ASTM A1064/A1064M, which consolidates plain and deformed wire and welded wire reinforcement into a single standard. ASTM A1064 replaces the withdrawn ASTM A185 (plain) and ASTM A497 (deformed) specifications. Where legacy Contract Documents reference ASTM A185 or ASTM A497, the Contractor shall supply material meeting ASTM A1064, which is the current specification.
WWR is furnished as flat sheets or rolls. Sheets are preferred for formed slabs where the mat must be placed at a specific elevation without continuous reshaping; rolls are common for slabs-on-grade and for elements where continuous longitudinal feed is practical. WWR spacing and wire sizes shall be as indicated on the Contract Drawings.
All deformed reinforcing bars shall be permanently marked with raised deformations and mill identification marks, in accordance with ASTM A615, A706, A1035, or the applicable specification, so that bar grade, producing mill, and bar size can be determined from visual inspection at the project site. Bars that cannot be positively identified shall be rejected or tested to confirm grade before incorporation into the work. Epoxy-coated bars shall retain legible identification marks through the coating; where marks are obscured, the bar ends shall be tagged or color-coded in accordance with the ASTM standard and the coater's identification system.
Reinforcing bars shall be fabricated in accordance with the reviewed shop drawings, the CRSI Manual of Standard Practice, and the applicable ASTM material specification. Fabrication shall include all cutting to length, bending, assembly of reinforcement cages, and application of identification tags. Bars shall be fabricated to the standard bending tolerances of the CRSI Manual of Standard Practice; dimensions flagged as "Critical" on the shop drawings shall be held to the tighter tolerances noted there.
Bars shall not be re-bent or straightened in a manner that damages the steel. Cold-bending of bars in the field is permitted only for minor adjustments and shall not be done for No. 8 bars and larger without written approval of the Engineer of Record and compliance with ACI 318-19 Section 26.6.2.
All bars shall be cold-bent. Hot bending is not permitted unless approved in writing by the Engineer of Record and accompanied by heat treatment to restore properties. Standard hooks shall be formed to the minimum inside bend diameters specified in ACI 318-19 Table 25.3.1 and detailed in the CRSI Manual of Standard Practice.
The minimum inside bend diameters for standard hooks are: No. 3 through No. 8 bars — 6db (where db is the nominal bar diameter); No. 9, 10, and 11 bars — 8db; No. 14 and 18 bars — 10db. Stirrups and ties follow reduced bend diameter requirements per ACI 318-19 Table 25.3.2. Bends of less than these minimum diameters crack the bar surface and damage the transverse deformations, reducing both tensile capacity and bond to concrete.
Standard fabrication tolerances, as given in the CRSI Manual of Standard Practice, apply to all bars unless the shop drawings designate specific dimensions as Critical. Fabrication tolerances are: cut length — ±1 in.; overall bent length of bar — ±1 in.; depth of stirrups, ties, and spirals — ±3/8 in.; location of bends — ±1 in. Dimensions flagged as Critical shall be held to ±1/4 in.
The Contractor shall be aware that fabrication tolerances accumulate with placement tolerances. Where bar positions are critical — for example, in precast elements, in elements with post-tensioning ducts, or in elements with closely spaced bars — the sum of fabrication and placement tolerances shall be evaluated to confirm that specified cover is achievable.
Where headed bars are specified for development, discontinuation at walls or discontinuous edges, or connections to precast elements, heads shall be forged or mechanically attached and shall conform to ASTM A970/A970M. The bearing area of the head shall be not less than four times the cross-sectional area of the bar, in accordance with ACI 318-19 Section 25.4.4, unless a larger ratio is required on the Contract Drawings.
Fabricated reinforcing steel shall be stored above grade on supports that keep bars free of mud, debris, and standing water. Bars coated with mud or other deleterious material shall be cleaned before placement. Light surface rust on uncoated bars does not reduce bond to concrete and is not cause for rejection; bars with heavy flaking rust, pitting, or mill scale that reduces the effective cross-section shall be rejected. Epoxy-coated and galvanized bars shall be stored in a manner that prevents coating damage; bars shall not be stockpiled in direct contact with each other without protective packaging.
Reinforcement shall be placed in accordance with the reviewed shop drawings and shall be secured in position before and during concrete placement. No reinforcing bar shall be moved during concrete placement except under the direct observation and approval of the Engineer of Record. Bars displaced during concrete placement shall be restored to correct position before the concrete takes initial set.
Bars shall be placed in the positions, at the spacings, and to the concrete cover shown on the Contract Drawings and shop drawings. Placement shall not deviate from the specified position by more than the tolerances given in ACI 117-10 (see Section 9 of this specification).
Minimum clear spacing between parallel bars shall be maintained to permit concrete to pass between bars and thoroughly surround each bar. ACI 318-19 Section 25.8.1 requires minimum clear spacing of not less than: the bar diameter (db), 1.33 times the nominal maximum aggregate size, and 1 in. These three requirements apply simultaneously; the controlling requirement shall govern.
Where bars are placed in two or more layers, bars in the upper layers shall be placed directly above those in the lower layer. The minimum clear distance between layers shall be 1 in., per ACI 318-19 Section 25.8.1.
All reinforcing bars shall be supported by bar supports (chairs, bolsters, spacers, or ties) that hold the bars in position within the specified tolerances and resist displacement during concrete placement and consolidation. Bar supports shall conform to CRSI RB4.1, Supports for Reinforcement Used in Concrete.
Bar support type shall be appropriate for the substrate and exposure. For slabs-on-grade, precast supports (concrete block chairs) or plastic-tipped wire supports may be used where direct contact with soil is unavoidable; plain wire supports shall not rest directly on compactible soil or fill because they settle and allow bars to drop. For elevated slabs and beams, all-plastic, plastic-protected, or stainless-steel-tipped wire supports shall be used at exposed surfaces or where metallic contact at the concrete surface would be visible or objectionable. For submerged or aggressive-exposure conditions, concrete or corrosion-resistant plastic supports shall be used; bare wire supports shall not be used in marine or de-icing salt exposure.
Supports shall be spaced so that bars do not sag between supports by more than the applicable ACI 117 tolerance. For No. 5 and smaller bars, support spacing shall not exceed 48 in.; for No. 6 and larger bars, support spacing shall not exceed 60 in., unless the fabricator calculates and demonstrates that sag at the support midpoint remains within tolerance at the specified support spacing.
Bars shall be tied at intersections at sufficient spacing to hold all bars in their correct positions during concrete placement. All bar intersections at the perimeter of each mat or cage shall be tied. Interior intersections shall be tied at every other intersection in a checkerboard pattern, or at closer spacing as directed by the Engineer of Record or Special Inspector when the mat configuration or the vibration conditions require closer tying. Wire used for tying shall be annealed iron wire; for epoxy-coated or galvanized bars, plastic-coated or stainless steel tie wire shall be used to avoid contact corrosion and coating damage from cutting tie wire ends.
Tie wire ends shall be bent away from the concrete surface so that the wire tail does not end up within the concrete cover zone. A protruding tie wire tail creates a direct corrosion path from the bar to the surface; this field practice error is one of the most common causes of concrete surface staining and early reinforcement corrosion.
WWR sheets shall be lapped at least one mesh spacing plus 2 in. in each direction, or as required by ACI 318-19 Chapter 25 for the specified spacing and wire grade, whichever is greater. Where the Contract Drawings require a specific lap, that lap shall govern. WWR rolls shall be unrolled, lapped, and weighted or tied to prevent spring-back before concrete is placed. WWR shall not be placed flat and then raised during concrete placement ("pulling wire" during placement is not permitted) because it does not reliably achieve the specified cover and placement position.
Concrete cover is the clear distance from the concrete surface to the outer face of the outermost reinforcing bar (including stirrups, ties, or spirals, which are the outermost bars in most beams and columns). Cover requirements are specified in ACI 318-19 Table 20.6.1 and reflect both structural requirements (bond development length depends on cover) and durability requirements (cover is the primary barrier preventing chloride, carbonation, and moisture from reaching the steel).
The minimum concrete cover requirements below apply unless the Contract Drawings specify greater cover. Greater cover than the tabulated minimum shall always govern.
For concrete cast against and permanently exposed to earth (footings, grade beams, pile caps cast against soil): 3 in.
For concrete exposed to earth or weather (garage decks, exterior slabs, surfaces in regular contact with moisture or freezing-and-thawing): No. 6 through No. 18 bars — 2 in.; No. 5 bars and smaller — 1-1/2 in.
For concrete not exposed to weather or in contact with ground — primary reinforcement in beams, girders, and columns: 1-1/2 in. Slabs, walls, joists: No. 5 bars and smaller — 3/4 in.; No. 6 through No. 11 bars — 1-1/2 in.
These are code minima. The Engineer of Record shall specify greater cover on the Contract Drawings for elements in high-chloride environments, for elements with large aggregates, for fire-resistance requirements beyond code minimum, or where any other condition warrants increased protection.
For epoxy-coated bars, ACI 318-19 does not reduce the specified concrete cover below the values for uncoated bars. The coating reduces the rate of corrosion once chloride reaches the bar, but it does not reduce the required minimum cover, which serves the dual purposes of durability and bond development. Galvanized bars similarly shall be placed to the same minimum cover requirements as uncoated bars. Specifying cover less than the tabulated minimums for coated bars is not permitted.
Where the structural element must satisfy a fire-resistance rating under IBC Chapter 7 or under ACI 216.1, the required concrete cover for fire resistance shall be compared against the cover required for structural and durability purposes, and the greater value shall be used. For slabs, beams, columns, and walls in high-occupancy buildings, fire-resistance requirements frequently control cover. The Contract Drawings shall indicate fire-resistance requirements that govern cover.
Splices are necessary whenever bar lengths exceed available mill lengths (typically 60 ft), where construction joints require transition between elements, and where bar congestion or structural analysis requires staged termination of bars. Splices shall be designed and located by the Engineer of Record. The Contractor shall not relocate or add splices without written approval from the Engineer of Record.
Every splice shall either develop the full tensile capacity of the bars being spliced (Type 2 performance, required in ductile seismic zones and frequently specified for critical structural elements) or develop at least 125 percent of the specified yield strength of the bars (Type 1 performance, which is the code minimum for most non-seismic applications). The Contract Drawings shall designate which type of performance is required for each splice location.
Tension lap splice length shall be determined by the Engineer of Record in accordance with ACI 318-19 Sections 25.5.2 and 25.5.7, based on the development length (ld) for the bar in the given concrete strength and cover condition, and the class of splice:
Class A tension lap splice: 1.0 × ld. Class A splices are permitted when at most 50 percent of the bars within the lap splice length are spliced and the provided area of reinforcement is at least twice the required area.
Class B tension lap splice: 1.3 × ld. Class B splices are required in all other cases, including where more than 50 percent of the bars are spliced at the same cross-section.
The default for this specification shall be Class B unless the Engineer of Record specifically designates Class A on the Contract Drawings. Class B is more conservative, is independent of the staggering condition, and reduces the risk of errors when splice staggering is not strictly maintained in the field.
Lap splices are not permitted for No. 14 and No. 18 bars. For these bar sizes, mechanical couplers or welded splices shall be used. Lap splices in bars subjected to direct compression (columns, piers) follow compression lap splice requirements per ACI 318-19 Section 25.5.5.
For bars in pure compression (columns, pedestals, compression zone of beams), the compression lap splice length shall be not less than the larger of: 0.0005 × fy × db (in.) and 12 in., per ACI 318-19 Section 25.5.5.1, where fy is the specified yield strength in psi and db is the nominal bar diameter in inches. For Grade 60 bars, this gives 0.0005 × 60,000 × db = 30db, with a 12 in. minimum.
Where ties or spirals enclose compression splices, reduced compression splice lengths may be permitted per ACI 318-19 Table 25.5.5.2 when approved by the Engineer of Record.
Where the Contract Drawings designate mechanical splices, couplers shall be installed in accordance with the reviewed product data and the manufacturer's installation instructions. Coupler type and performance classification shall be as specified on the Contract Drawings:
Type 1 mechanical splice: shall develop at least 125 percent of the specified yield strength of the bar in tension and compression.
Type 2 mechanical splice: shall develop at least 125 percent of the specified yield strength and shall also develop the specified tensile strength (ultimate capacity) of the bar. Type 2 splices are required by ACI 318-19 for specific locations in special moment frames, special structural walls, and other seismic elements where the connection must remain effective after the bar yields.
The Contractor shall not substitute a different coupler type without written approval from the Engineer of Record, because the Type 1 vs. Type 2 distinction reflects a structural design decision, not an installer preference.
End-bearing compression splices, in which bars are cut square and the ends bear in direct contact to transfer compression, are permitted for No. 10 bars and larger in pure compression applications where approved by the Engineer of Record. Bars shall be cut so that end bearing surfaces are within 1.5 degrees of perpendicular to the bar axis. An end-bearing splice shall be restrained against lateral displacement by ties or other means at each end of the splice. End-bearing splices shall not be used in tension zones or where bars experience reversing stresses.
Field welding of reinforcing bars shall be minimized and shall be permitted only where specifically required by the Contract Drawings or approved in writing by the Engineer of Record. Welding is not a substitute for proper lap splice length or mechanical coupler installation, and it introduces heat that can alter bar metallurgy and reduce ductility. Where welding is required, the following requirements shall apply.
Only bars verified as weldable shall be field-welded. ASTM A706 bars are weldable by specification and may be welded without chemical analysis. ASTM A615 bars require carbon equivalent testing of each heat before welding to determine preheat requirements per AWS D1.4. ASTM A1035 bars have restricted weldability due to their high-chromium chemistry and shall not be welded unless the Engineer of Record, the fabricator, and the AWS D1.4 qualified welding engineer have all reviewed and approved a specific welding procedure specification (WPS).
All welding shall be performed in accordance with a Welding Procedure Specification (WPS) qualified in accordance with AWS D1.4/D1.4M. The WPS shall address: base metal grade and carbon equivalent range, filler metal classification, preheat and interpass temperature, joint geometry, welding process, and position. Welding shall not begin until the WPS has been submitted to and reviewed by the Engineer of Record. Preheat temperatures shall be maintained throughout the welding operation and not relaxed until the weld is complete and allowed to cool per the WPS.
Welding operators shall be certified to AWS D1.4 for the welding process and positions used. Certification records shall be current (within three years) and available to the Special Inspector on request. Tack welding of bars in position shall not be performed by uncertified workers.
The following practices are prohibited without exception: welding to any bar unless it is confirmed weldable per the requirements above; welding of crossing bars (tack welding of tie intersections to act as permanent connections) unless specifically designed as welded connections by the Engineer of Record; weld splices where lap splices or mechanical couplers are required on the Contract Drawings; and welding of any bar with visible cracks, seams, or surface defects.
Tolerances for placement of reinforcing steel shall be as specified in ACI 117-10. The following apply to nonprestressed reinforcement:
Effective depth (d) and clear cover to formed surfaces: For members where d ≤ 8 in., tolerance is ±3/8 in. For members where d > 8 in. and ≤ 24 in., tolerance is ±1/2 in. For members where d > 24 in., tolerance is ±1 in. These tolerances apply to the position of the bar measured from the relevant reference face.
The ACI 117 tolerance on cover reduction is limited: the reduction in concrete cover shall not exceed one-third of the specified concrete cover, and the reduction in cover to formed soffits shall not exceed 1/4 in.
Longitudinal position of bends and bar ends: ±2 in. except at discontinuous ends where tolerance is ±1/2 in.
Spacing between bars: ±1/4 in. for bars at 12 in. on center or less; ±1/2 in. for bars at more than 12 in. on center.
The Contractor shall be aware that the ACI 318-19 tolerances on effective depth are design check tolerances — they reflect the expected range in which a well-built element may differ from the design drawing and are used in strength calculations. They are not instructions to the Contractor to place bars at the extreme tolerance limit. The placement target is the specified position; tolerances are a range that may not be deliberately approached.
Lap splice lengths and development lengths shall meet the specified minimum; no negative tolerance is permitted for development length or lap splice length. The Contractor shall ensure that bars are long enough, and that stagger is maintained, so that every bar develops its required capacity. A lap splice that is 1/2 in. short of the specified length is a nonconformance requiring Engineering evaluation regardless of the ACI 117 position tolerances.
Bar size substitution shall not be made without written approval of the Engineer of Record. Substituting a smaller number of larger bars for a larger number of smaller bars, or vice versa, changes the development length, bar spacing, concrete cover, and cracking behavior of the element. These parameters are all interdependent and require Engineering analysis before any substitution.
Before any concrete is placed, the Contractor shall perform a pre-placement inspection of all reinforcement in the element and shall confirm: bar grades and sizes match the shop drawings; bars are clean, properly positioned, and secured; cover is correct at all locations; lap splices are at correct locations and of correct length; mechanical couplers are fully engaged per manufacturer requirements; bar supports are correctly placed and are of the specified type; tie wire tails are bent inward; and there are no displaced, bent, or cut bars that deviate from the shop drawings.
The pre-placement inspection shall be documented on a checklist. For elements subject to special inspection, the Special Inspector's observation shall be recorded. Concrete shall not be placed until the pre-placement inspection is complete and any deficiencies are corrected.
The Special Inspector for reinforcing steel shall perform the following at minimum, in accordance with the Statement of Special Inspections:
Verify that reinforcing bar grade and size match the Contract Documents and reviewed shop drawings. Bars shall be identified by their deformation markings. No bar shall be placed without positive identification of grade.
Measure concrete cover at representative locations — at top, bottom, and side faces of each element — and record the measured values. Where cover measurements indicate a potential violation of the ACI 117 tolerance, the Special Inspector shall immediately notify the Engineer of Record.
Verify lap splice lengths by measuring each splice in the element. Splice lengths shall be measured between bar ends; the measurement shall not include the bend of a hook.
Inspect mechanical couplers to confirm they are fully engaged — verify that the inspection hole on threaded couplers shows the bar end, that lock pins or set screws are tightened to the manufacturer's specified torque, and that no cross-threading or partial engagement is visible.
Verify that WWR laps are correct, that the sheets or rolls are at the correct elevation and are properly supported.
Observe welded splices and connections to confirm that welding is performed by a certified operator using a reviewed WPS and that visible weld quality meets AWS D1.4.
The Special Inspector shall measure concrete cover using a calibrated cover meter (pachometer) at representative points on the placed reinforcement. Measurements shall be taken at top bars in slabs (measuring from slab top surface to top bar if accessible, or from bottom surface to bottom bar), at slab and beam sides for side cover, and at beam soffits for bottom cover. Measurements shall be compared against the specified cover and the ACI 117 tolerance. Any measurement below the minimum cover minus the allowable tolerance shall be reported immediately and shall be corrected before concrete is placed.
The Special Inspector shall record measured bar spacing at representative locations. Bar spacing is measured center-to-center at not less than three locations per element. The recorded spacings shall be compared against the specified spacing with the ACI 117 tolerance applied. Excess bar spacing weakens sections and increases crack width; deficient bar spacing can produce congestion that prevents concrete from flowing between bars.
Any reinforcement that does not conform to the Contract Documents, the reviewed shop drawings, or the requirements of ACI 318-19 and ACI 117 shall be documented as a nonconformance by the Special Inspector and reported to the Engineer of Record, the Contractor, and the Owner in writing before concrete is placed. Concrete shall not be placed over a documented nonconformance until the Engineer of Record has reviewed it and issued a written disposition. Dispositions shall be one of: reject and correct; accept as-is with justification (Engineering evaluation required); or accept with compensating action (added bars, reduced loads, or other mitigation).
During concrete placement, the Contractor shall assign a qualified individual to monitor reinforcement for displacement. Concrete vibrators shall not be used against reinforcing bars as a means of vibration; internal vibrators shall be inserted between bars and shall be operated in a manner that does not drag or dislodge bar mats. If reinforcement is displaced during placement, work shall be stopped, the bar shall be restored to position, and the cause of displacement shall be corrected before placement resumes.
Reinforcing steel shall be delivered to the project site in clearly labeled bundles identified by bar mark, size, grade, coating type, heat number, and quantity. Bundles shall carry certification tags that match the CMTRs submitted under Section 3. Bars shall not be accepted without traceable certification.
Bars shall be stored above grade on timber or other supports that keep bars clear of mud, standing water, and road dirt. Bars shall be stored in a manner that does not impose bending loads on fabricated shapes. Stirrups and small fabricated cages shall be supported to prevent permanent distortion. Epoxy-coated bars shall be stored in their original packaging or under protective covering to prevent UV degradation of the coating. Galvanized bars shall be stored so that bundled bars do not develop wet-storage staining (white rust) by allowing adequate air circulation between bars.
Bars shall be lifted and handled using nylon slings or other methods that do not score, nick, or damage the bar surface or coating. Wire rope slings shall not be used directly on epoxy-coated or galvanized bars. Bars shall not be dropped from height onto hard surfaces; impact can crack epoxy coatings and cause bar deformation at bends.
The Contractor shall warrant the reinforcement installation against defects in workmanship — including incorrect bar grades, inadequate cover, insufficient splice length, and improper coupler installation — for the project warranty period. The warranty shall not limit the Engineer of Record's right to perform special inspection, to require corrective work for nonconforming conditions, or to require the Contractor to expose and remediate reinforcement that was placed in a noncompliant condition.
Material warranties provided by the bar manufacturer or the coating applicator shall be passed through to the Owner. For epoxy-coated bars, the coater's warranty against coating delamination (where provided) shall be documented and included in the closeout submittals.