Heads up: There are no amended sections in this chapter.
This chapter addresses (a) through (c):
- Design information that the licensed design professional shall specify in the construction documents, if applicable.
- Compliance requirements that the licensed design professional shall specify in the construction documents, if applicable.
- Inspection requirements that the licensed design professional shall specify in the construction documents, if applicable.
- Design work delegated to the contractor shall be performed by a specialty engineer.
- The contractor's specialty engineer, relying on the documents identifying the portion of design work assigned, shall produce design work that is compatible with the construction documents and the design criteria provided by the licensed design professional in charge of the design work.
- The contractor shall submit necessary information to the licensed design professional to confirm that the specialty engineer complied with the documents identifying the portion of the design work assigned.
- Cementitious materials shall conform to the specifications in Table 188.8.131.52.1(a), except as permitted in 184.108.40.206.1(b).
Table 220.127.116.11.1(a)—Specifications for cementitious materials
Cementitious material Specification Portland cement ASTM C150 Blended hydraulic cements ASTM C595, excluding Type IS (≥70) and Type IT (S ≥ 70) Expansive hydraulic cement ASTM C845 Hydraulic cement ASTM C1157 Fly ash and natural pozzolan ASTM C618 Slag cement ASTM C989 Silica fume ASTM C1240
- Alternative cements shall be permitted if approved by the licensed design professional and the building official. Approval shall be based upon test data documenting that the proposed concrete mixture made with the alternative cement meets the performance requirements for the application including structural, fire, and durability.
- Aggregates shall conform to (1) or (2):
- Normalweight aggregate: ASTM C33.
- Lightweight aggregate: ASTM C330.
- Aggregates not conforming to ASTM C33 or ASTM C330 are permitted if they have been shown by test or actual service to produce concrete of adequate strength and durability and are approved by the building official.
- Crushed hydraulic-cement concrete or recycled aggregate shall be permitted if approved by the licensed design professional and the building official based on documentation that demonstrates compliance with (1) and (2).
- Concrete incorporating the specific aggregate proposed for the Work has been demonstrated to provide the mechanical properties and durability required in structural design.
- A testing program to verify aggregate consistency and a quality control program to achieve consistency of properties of the concrete are conducted throughout the duration of the project.
- For shotcrete, the aggregate gradation shall conform to ASTM C1436.
- Admixtures shall conform to (1) through (4):
- Water reduction and setting time modification: ASTM C494.
- Producing flowing concrete: ASTM C1017.
- Air entrainment: ASTM C260.
- Inhibiting chloride-induced corrosion: ASTM C1582.
- Admixtures that do not conform to the specifications in 18.104.22.168.1(a) shall be subject to prior review by the licensed design professional.
- Admixtures used in concrete containing expansive cements conforming to ASTM C845 shall be compatible with the cement and produce no deleterious effects.
- Admixtures used in shotcrete shall conform to ASTM C1141.
- (a) Requirements (1) through (17) for each concrete mixture, based on assigned exposure classes or design of members:
- Minimum specified compressive strength of concrete, fc'.
- Minimum modulus of elasticity of concrete, Ec, if specified in accordance with 22.214.171.124.
- Test age, if different from 28 days, for demonstrating compliance with fc' and Ec if specified.
- Maximum w/cm applicable to most restrictive assigned durability exposure class from 126.96.36.199.
- Nominal maximum size of coarse aggregate not to exceed the least of (i), (ii), and (iii):
- Applicable air content for Exposure Category F from 188.8.131.52 or 184.108.40.206.
- For members assigned to Exposure Class F3, indicate that concrete mixtures shall meet the limits on supplementary cementitious materials in Table 220.127.116.11(b).
- For members assigned to Exposure Class S1, S2, or S3, indicate that mineral fillers derived from carbonate aggregate are prohibited unless approved by the licensed design professional.
- Applicable cementitious materials for Exposure Category S from 18.104.22.168.
- For members assigned to Exposure Category S, indicate if alternative combinations of cementitious materials qualified in accordance with 22.214.171.124(c) are permitted.
- Members in which calcium chloride is prohibited because of assignment to Exposure Class S2 or S3.
- For members assigned to exposure class W1 or W2, requirements for the evaluation of the potential for alkali-aggregate reactivity.
- Applicable water-soluble chloride ion limits for Exposure Category C from 126.96.36.199.
- Equilibrium density of lightweight concrete.
- Requirement for submittal of the volumetric fractions of aggregate in lightweight concrete mixtures if Table 188.8.131.52(b) is used as the basis for λ in design.
- Requirements for steel fiber-reinforced concrete if used for shear resistance in accordance with 184.108.40.206.
- For shotcrete, nominal maximum size of coarse aggregate shall not exceed 1/2 in.
- At the option of the licensed design professional, exposure classes based on the severity of the anticipated exposure of members.
- The required compressive strength at designated stages of construction for each part of the structure designed by the licensed design professional.
- The required compressive strength at designated stages of construction for each part of the structure not designed by the licensed design professional shall be submitted for review.
- For members identified in construction documents as subject to cycles of freezing and thawing and application of deicing chemicals, supplementary cementitious materials, including fly ash and natural pozzolans, silica fume, and slag cement, shall not exceed the maximum percentage allowed in Table 220.127.116.11(b) and shall satisfy (1) and (2).
- Supplementary cementitious materials, including fly ash and natural pozzolans, silica fume, and slag cement, used in the manufacture of ASTM C595 and C1157 blended cements shall be included in assessing compliance with the limits in Table 18.104.22.168(b).
- The individual limits in Table 22.214.171.124(b) shall apply regardless of the number of cementitious materials in a concrete mixture.
Supplementary cementitious materials Maximum percent of total cementitious materials by mass Fly ash or natural pozzolans conforming to ASTM C618 25 Slag cement conforming to ASTM C989 50 Silica fume conforming to ASTM C1240 10 Total of fly ash or natural pozzolans and silica fume 35 Total of fly ash or natural pozzolans, slag cement, and silica fume 50
- For concrete mixtures for members identified in construction documents to be exposed to sulfate, alternative combinations of cementitious materials to those specified in 126.96.36.199(a)(9) are permitted if tests for sulfate resistance satisfy the criteria in Table 188.8.131.52(c).
Table 184.108.40.206(c)—Requirements for establishing suitability of combinations of cementitious materials for Exposure Category S
Exposure class Maximum length change for tests in accordance with ASTM C1012, percent At 6 months At 12 months At 18 months S1 0.10 No requirement No requirement S2 0.05 0.10 No requirement S3 Option 1 No requirement No requirement 0.10 Option 2 0.05 0.10 No requirementThe 12-month expansion limit applies only if the measured expansion exceeds the 6-month maximum expansion limit.
- For concrete identified as being exposed to water in service, evidence shall be submitted that the concrete mixture complies with (1) and (2).
- Aggregates are not alkali-silica reactive or measures to mitigate alkali-silica reactivity have been established.
- Aggregates are not alkali-carbonate reactive.
- Compliance with the specified chloride ion content limits shall be demonstrated by (1) or (2).
- Calculating total chloride ion content of the concrete mixture on the basis of measured total chloride ion content from concrete materials and concrete mixture proportions.
- Determining water-soluble chloride ion content of hardened concrete in accordance with ASTM C1218 at age between 28 and 42 days.
- For prestressed concrete, admixtures containing calcium chloride are prohibited.
- For concrete placed on or against stay-in-place galvanized steel forms, maximum water soluble chloride ion content shall be 0.30 percent by mass of cementitious materials unless a more stringent limit for the member is specified.
- For lightweight concrete, fresh density shall be determined in accordance with ASTM C138 that corresponds with the specified equilibrium density determined in accordance with ASTM C567. The fresh density corresponding to the specified equilibrium density shall be used as the basis of acceptance.
- Steel fiber-reinforced concrete used for shear resistance shall satisfy (1) and (2):
- Conform to ASTM C1116.
- Contain at least 100 lb of deformed steel fibers per cubic yard of concrete.
- Concrete mixture proportions shall be established so that the concrete satisfies (1) through (4):
- Can be placed without segregation and fully encase reinforcement.
- Meets durability requirements given in the construction documents.
- Conforms to strength test requirements for standard-cured specimens.
- Conforms to modulus of elasticity requirements (i) through (iii) for mixtures requiring testing in accordance with construction documents.
- The modulus of elasticity shall be determined as the average modulus obtained from at least three cylinders made from the same sample of concrete and tested at 28 days or at test age designated for Ec.
- Cylinders used to determine modulus of elasticity shall be made and cured in the laboratory in accordance with ASTM C192 and tested in accordance with ASTM C469.
- Modulus of elasticity of a concrete mixture shall be acceptable if the measured value equals or exceeds the specified value.
- Concrete mixture proportions shall be established in accordance with Article 4.2.3 of ACI 301 or by an alternative method acceptable to the licensed design professional. Alternative methods shall have a probability of satisfying the strength requirements for acceptance tests of standard-cured specimens that meets or exceeds the probability associated with the method in Article 4.2.3 of ACI 301. If Article 4.2.3 of ACI 301 is used, the strength test records used for establishing and documenting concrete mixture proportions shall not be more than 24 months old.
- The concrete materials used to develop the concrete mixture proportions shall correspond to those to be used in the proposed Work.
- If different concrete mixtures are to be used for different portions of proposed Work, each mixture shall comply with the concrete mixture requirements stated in the construction documents.
- Shotcrete mixture proportions shall be established so that shotcrete satisfies (1) through (3):
- Documentation of concrete mixture characteristics shall be submitted for review by the licensed design professional before the mixture is used and before making changes to mixtures already in use. Evidence of the ability of the proposed mixture to comply with the fresh and hardened concrete mixture requirements in the construction documents shall be included in the documentation. The evidence shall include records of consecutive strength tests, as defined in 220.127.116.11, of the same concrete mixture used in previous projects or the results of laboratory trial batches of the proposed mixture.
- If field or laboratory test data are not available, and fc' ≤ 5000 psi, concrete proportions shall be based on other experience or information, if approved by the licensed design professional. If fc' > 5000 psi, test data documenting the characteristics of the proposed mixtures are required.
- It shall be permitted to modify mixtures during the course of the Work. Before using the modified mixture, evidence acceptable to the licensed design professional shall be submitted to demonstrate that the modified mixture complies with the concrete mixture requirements in the construction documents.
- Documentation of shotcrete mixture characteristics shall be submitted for review by the licensed design professional before the mixture is used and before making changes to mixtures already approved. Evidence of the ability of the proposed shotcrete mixture to comply with the shotcrete mixture requirements in the construction documents shall be included in the documentation.
- Cementitious materials and aggregates shall be stored to prevent deterioration or contamination.
- Material that has deteriorated or has been contaminated shall not be used in concrete.
- Equipment for mixing and transporting concrete shall conform to ASTM C94 or ASTM C685.
- Ready-mixed and site-mixed concrete shall be batched, mixed, and delivered in accordance with ASTM C94 or ASTM C685.
- Debris and ice shall be removed from spaces to be occupied by concrete before placement.
- Standing water shall be removed from place of deposit before concrete is placed unless a tremie is to be used or unless otherwise permitted by both the licensed design professional and the building official.
- Equipment used to convey concrete from the mixer to the location of final placement shall have capabilities to achieve the placement requirements.
- Concrete shall not be pumped through pipe made of aluminum or aluminum alloys.
- Concrete shall be placed in accordance with (1) through (5):
- At a rate to provide an adequate supply of concrete at the location of placement.
- At a rate so concrete at all times has sufficient workability such that it can be consolidated by the intended methods.
- Without segregation or loss of materials.
- Without interruptions sufficient to permit loss of workability between successive placements that would result in cold joints.
- Deposited as near to its final location as practicable to avoid segregation due to rehandling or flowing.
- Concrete that has been contaminated or has lost its initial workability to the extent that it can no longer be consolidated by the intended methods shall not be used.
- Retempering concrete in accordance with the limits of ASTM C94 shall be permitted unless otherwise restricted by the licensed design professional.
- After starting, concreting shall be carried on as a continuous operation until the completion of a panel or section, as defined by its boundaries or predetermined joints.
- Concrete shall be consolidated by suitable means during placement and shall be worked around reinforcement and embedments and into corners of forms.
- Prior to placement of a new layer of shotcrete, rebound and overspray from adjacent placements shall be removed.
- Cuttings and rebound shall not be incorporated into the Work.
- Shotcrete surfaces intended to receive subsequent shotcrete placement shall be roughened to a full amplitude of approximately 1/4 in. before the shotcrete has reached final set.
- Before placing additional material onto hardened shotcrete, laitance shall be removed, joints shall be cleaned, and the surface shall be dampened.
- In-place fresh shotcrete that exhibits sags, sloughs, segregation, honeycombing, or sand pockets shall be removed and replaced.
- A certified shotcrete nozzle operator shall place all shotcrete.
- If a project-specific shotcrete mockup panel is required, each nozzle operator shall have demonstrated the ability to shoot an approved shotcrete mockup panel.
- If supplementary tests of field-cured specimens are required to verify adequacy of curing and protection, the number and size of test specimens and the frequency of these supplementary tests.
- Concrete, other than high-early-strength, shall be maintained at a temperature of at least 50°F and in a moist condition for at least the first 7 days after placement, except if accelerated curing is used.
- High-early-strength concrete shall be maintained at a temperature of at least 50°F and in a moist condition for at least the first 3 days after placement, except if accelerated curing is used.
- Accelerated curing to accelerate strength gain and reduce time of curing is permitted using high-pressure steam, steam at atmospheric pressure, heat and moisture, or other process acceptable to the licensed design professional. If accelerated curing is used, (1) and (2) shall apply:
- If required by the building official or licensed design professional, test results for cylinders made and cured in accordance with (1) and (2) shall be provided in addition to test results for standard-cured cylinders.
- At least two 6 × 12 in. or at least three 4 × 8 in. cylinders to be field cured shall be molded at the same time and from the same samples as standard-cured cylinders.
- Field-cured cylinders shall be cured in accordance with the field curing procedure of ASTM C31 and tested in accordance with ASTM C39.
- Procedures for protecting and curing concrete shall be considered adequate if (1) or (2) are satisfied:
- Shotcrete shall be cured in accordance with (1) through (3).
- For 24 hours from completion of placement, initial curing shall be provided by one of the following methods:
- Ponding, fogging, or continuous sprinkling;
- Absorptive mat, fabric, or other protective covering kept continuously moist;
- Application of a membrane-forming curing compound.
- After 24 hours from completion of placement, final curing shall be provided by one of the following methods:
- Same method used in the initial curing process;
- Sheet materials;
- Other moisture-retaining covers kept continuously moist.
- Final curing shall be maintained for a minimum duration of:
- 7 days,
- 3 days if either a high-early-strength cement or an accelerating admixture is used.
- For 24 hours from completion of placement, initial curing shall be provided by one of the following methods:
- Adequate equipment shall be provided for heating concrete materials and protecting concrete during freezing or near-freezing weather.
- Frozen materials or materials containing ice shall not be used.
- Forms, fillers, and ground with which concrete is to come in contact shall be free from frost and ice.
- Concrete materials and production methods shall be selected so that the concrete temperature at delivery complies with the specified temperature limits.
- Concrete materials and production methods shall be selected so that the concrete temperature at delivery complies with the specified temperature limits.
- Handling, placing, protection, and curing procedures shall limit concrete temperatures or water evaporation that could reduce strength, serviceability, and durability of the member or structure.
- If required by the design, locations and details of construction, isolation, and contraction joints.
- Details required for transfer of shear and other forces through construction joints.
- Surface preparation, including intentional roughening of hardened concrete surfaces where concrete is to be placed against previously hardened concrete.
- Locations where shear is transferred between as-rolled steel and concrete using headed studs or welded reinforcing bars requiring steel to be clean and free of paint.
- Surface preparation including intentional roughening if composite topping slabs are to be cast in place on a precast floor or roof intended to act structurally with the precast members.
- For shotcrete, location of construction joints for which square joints are permitted.
(a) Joint locations or joint details not shown or that differ from those indicated in construction documents shall be submitted for review by the licensed design professional.
(b) Except for prestressed concrete, construction joints in floor and roof systems shall be located within the middle third of spans of slabs, beams, and girders unless otherwise approved by the licensed design professional.
(c) Construction joints in girders shall be offset a distance of at least two times the width of intersecting beams, measured from the face of the intersecting beam, unless otherwise approved by the licensed design professional.
(f) Immediately before new concrete is placed, construction joints shall be prewetted and standing water removed.
(g) For shotcrete, construction joint surfaces shall be cut at a 45-degree angle to the finished surface, unless a square joint is designated in the construction documents.
- Details required to accommodate dimensional changes resulting from prestressing, creep, shrinkage, and temperature.
- Identify if a slab-on-ground is designed as a structural diaphragm or part of the seismic-force-resisting system.
- Details for construction of sloped or stepped footings designed to act as a unit.
- Locations where floor system and column concrete placements are required to be integrated during placement in accordance with 15.5.
- Locations where steel fiber-reinforced concrete is required for shear resistance in accordance with 18.104.22.168.
- Beams, girders, or slabs supported by columns or walls shall not be cast until concrete in the vertical support members is no longer plastic.
- Beams, girders, haunches, drop panels, shear caps, and capitals shall be placed monolithically as part of a slab system, unless otherwise shown in construction documents.
- At locations where floor system and column concrete placements are required to be integrated during placement, column concrete shall extend full depth of the floor system at least 2 ft into the floor system from face of column and be integrated with floor system concrete.
- Saw cutting or construction of joints that can affect the integrity of a slab-on-ground identified in the construction documents as structural diaphragms or part of the seismic-force-resisting system shall not be permitted unless specifically indicated or approved by the licensed design professional.
- ASTM designation and grade of reinforcement, including applicable requirements for special seismic systems in accordance with 22.214.171.124.
- Type, size, location requirements, detailing, and embedment length of reinforcement.
- Concrete cover to reinforcement.
- Location and length of lap splices.
- Type and location of mechanical splices.
- Type and location of end-bearing splices.
- Type and location of welded splices and other required welding of reinforcing bars.
- ASTM designation for protective coatings of nonprestressed reinforcement.
- Corrosion protection for exposed reinforcement intended to be bonded with extensions on future Work.
- Mill test reports for reinforcement shall be submitted.
- Nonprestressed reinforcement with rust, mill scale, or a combination of both shall be considered satisfactory, provided a hand-wire-brushed representative test specimen of the reinforcement complies with the applicable ASTM specification for the minimum dimensions (including height of deformations) and weight per unit length.
- Prestressing reinforcement shall be free of mill scale, pitting, and excessive rust. A light coating of rust shall be permitted.
- At the time concrete is placed, reinforcement to be bonded shall be clean of ice, mud, oil, or other deleterious coatings that decrease bond.
- Tolerances on location of reinforcement taking into consideration tolerances on d and specified concrete cover in accordance with Table 126.96.36.199(a).
Table 188.8.131.52(a)—Tolerances on d and specified cover
d, in. Tolerance on d, in. Tolerance on specified concrete cover, in. ≤ 8 ±3/8 Smaller of: —3/8 — (1/3) • specified cover > 8 ±1/2 Smaller of: —1/2 — (1/3) • specified coverTolerance for cover to formed soffits is —1/4 in.
- Tolerance for longitudinal location of bends and ends of reinforcement in accordance with Table 184.108.40.206(b). The tolerance for specified concrete cover in Table 220.127.116.11(a) shall also apply at discontinuous ends of members.
- Tolerance for spacing of hoops in members of intermediate and special seismic systems:
- Lesser of +1-1/2 in. and +1.5db of the smallest longitudinal bar.
- Lesser of —1 in. per ft of least side dimension of member and —3 in.
- Spacing adjustments shall result in no more than two hoops being in contact with each other.
- Reinforcement, including bundled bars, shall be placed within required tolerances and supported to prevent displacement beyond required tolerances during concrete placement.
- Spiral units shall be continuous bar or wire placed with even spacing and without distortion beyond the tolerances for the specified dimensions.
- Splices of reinforcement shall be made only as permitted in the construction documents, or as authorized by the licensed design professional.
- For longitudinal column bars forming an end-bearing splice, the bearing of square cut ends shall be held in concentric contact.
- Bar ends shall terminate in flat surfaces within 1.5 degrees of a right angle to the axis of the bars and shall be fitted within 3 degrees of full bearing after assembly.
- Reinforcement shall be bent cold prior to placement, unless otherwise permitted by the licensed design professional.
- Field bending of reinforcement partially embedded in concrete shall not be permitted, except as shown in the construction documents or permitted by the licensed design professional.
- Offset bars shall be bent before placement in the forms.
- Welding of all nonprestressed bars shall conform to the requirements of AWS D1.4. ASTM specifications for bar reinforcement, except for ASTM A706, shall be supplemented to require a mill test report of material properties that demonstrate conformance to the requirements in AWS D1.4.
- Welding of crossing bars shall not be used for assembly of reinforcement except at the front face of brackets or corbels or as otherwise permitted by the licensed design professional.
- Requirements for assessment and qualification of anchors for the applicable conditions of use shall be in accordance with 17.1.2.
- Type, size, location requirements, effective embedment depth, and installation requirements for anchors.
- Type, size, and location or location requirements for anchor reinforcement designed to develop the anchor strength in accordance with 18.104.22.168, as well as transverse confinement reinforcement for anchors installed in the tops of columns or pedestals in accordance with 10.7.6.1.5.
- Type, size, and location for shear lugs designed to develop shear strength in accordance with 17.11.
- Size and location of base plate holes to permit inspection and vent air when placing concrete or grout per 22.214.171.124.
- Minimum edge distance of anchors in accordance with 17.9.
- Corrosion protection for exposed anchors intended for attachment with future Work.
- For post-installed anchors, parameters associated with the design strength in accordance with 17.5, including anchor category, concrete strength, aggregate type, type of lightweight concrete, required installation torque, and requirements for hole drilling and preparation.
- For adhesive anchors in tension, parameters associated with the characteristic bond stress used for design in accordance with 17.6.5, including concrete temperature range, moisture condition of concrete at time of installation, type of lightweight concrete, if applicable, and requirements for hole drilling and preparation.
- Identification of adhesive anchors installed in a horizontal or upwardly inclined orientation to resist sustained tensile loads.
- Identification of adhesive anchors requiring proof loading in accordance with ACI 355.4 or the inspection program established by the licensed design professional.
- Specify certification required for installers of adhesive anchors including adhesive anchors that are installed in a horizontal or upwardly inclined orientation to resist sustained tensile loads.
- Cast-in anchors, their attachments, and anchor reinforcement, shall be securely positioned in the formwork and oriented in accordance with the construction documents. Concrete shall be consolidated around anchors and anchor reinforcement using suitable means during placement.
- Proper consolidation of concrete or grout around shear lugs shall be verified by use of base plate inspection holes.
- Post-installed anchors shall be installed in accordance with the manufacturer's instructions. Post-installed adhesive anchors shall be installed in accordance with the Manufacturer's Printed Installation Instructions (MPII).
- Post-installed anchors shall be installed by qualified installers.
- Adhesive anchors identified in the construction documents as installed in a horizontal or upwardly inclined orientation to resist sustained tensile loads shall be installed by certified installers.
- Adhesive anchors shall be installed in concrete having a minimum age of 21 days at time of anchor installation.
- Type, size, details, and location of embedments designed by the licensed design professional.
- Reinforcement required to be placed perpendicular to pipe embedments.
- Specified concrete cover for pipe embedments with their fittings.
- Corrosion protection for exposed embedments intended to be connected with future Work.
- Type, size, details, and location of embedments not shown in the construction documents shall be submitted for review by the licensed design professional.
- Aluminum embedments shall be coated or covered to prevent aluminum-concrete reaction and electrolytic action between aluminum and steel.
- Pipes and fittings not shown in the construction documents shall be designed to resist effects of the material, pressure, and temperature to which they will be subjected.
- No liquid, gas, or vapor, except water not exceeding 90°F or 50 psi pressure, shall be placed in the pipes until the concrete has attained its specified strength.
- In solid slabs, piping, except for radiant heating or snow melting, shall be placed between top and bottom reinforcement.
- Conduit and piping shall be fabricated and installed so that cutting, bending, or displacement of reinforcement from its specified location is not required.
- Members shall be marked to indicate location and orientation in the structure and date of manufacture.
- Identification marks on members shall correspond to erection drawings.
- Design and details of lifting devices, embedments, and related reinforcement required to resist temporary loads from handling, storage, transportation, and erection shall be provided if not designed by the licensed design professional.
- During erection, precast members and structures shall be supported and braced to ensure proper alignment, strength, and stability until permanent connections are completed.
- If approved by the licensed design professional, items embedded while the concrete is in a plastic state shall satisfy (1) through (4):
- Embedded items shall protrude from the precast concrete members or remain exposed for inspection.
- Embedded items are not required to be hooked or tied to reinforcement within the concrete.
- Embedded items shall be maintained in the correct position while the concrete remains plastic.
- The concrete shall be consolidated around embedded items.
- Magnitude and location of prestressing forces.
- Stressing sequence of tendons.
- Type, size, details, and location of post-tensioning anchorages for systems selected by the licensed design professional.
- Tolerances for placement of tendons and post-tensioning ducts in accordance with Table 126.96.36.199(a).
- Materials and details of corrosion protection for tendons, couplers, end fittings, post-tensioning anchorages, and anchorage regions.
- Requirements for ducts for bonded tendons.
- Requirements for grouting of bonded tendons, including maximum water-soluble chloride ion (C1—) content requirements in 19.4.1.
- Type, size, details, and location of post-tensioning anchorage systems not shown in the construction documents shall be submitted to the licensed design professional for review.
- Tendons and post-tensioning ducts shall be placed within required tolerances and supported to prevent displacement beyond required tolerances during concrete placement.
- Couplers shall be placed in areas approved by the licensed design professional and enclosed in housings long enough to permit necessary movements.
- Burning or welding operations in the vicinity of prestressing reinforcement shall be performed in such a manner that prestressing reinforcement is not subject to welding sparks, ground currents, or temperatures that degrade the properties of the reinforcement.
- Prestressing force and friction losses shall be verified by (1) and (2).
- The cause of any difference in force determination between (1) and (2) of 26.10.2(e) that exceeds 5 percent for pretensioned construction or 7 percent for post-tensioned construction shall be ascertained and corrected, unless approved by the licensed design professional.
- Loss of prestress force due to unreplaced broken prestressed reinforcement shall not exceed 2 percent of the total prestress force in prestressed concrete members, unless approved by the licensed design professional.
- If the transfer of force from the anchorages of the pretensioning bed to the concrete is accomplished by flame cutting prestressed reinforcement, the cutting locations and cutting sequence shall be selected to avoid undesired temporary stresses in pretensioned members.
- Long lengths of exposed pretensioned strand shall be cut near the member to minimize shock to the concrete.
- Prestressing reinforcement in post-tensioned construction shall not be stressed until the concrete compressive strength is at least 2500 psi for single-strand or bar tendons, 4000 psi for multistrand tendons, or a higher strength, if required. An exception to these strength requirements is provided in 26.10.2(k).
- Lower concrete compressive strength than required by 26.10.2(j) shall be permitted if (1) or (2) is satisfied:
- Requirement for the contractor to design, fabricate, install, and remove formwork.
- Location of composite members requiring shoring.
- Requirements for removal of shoring of composite members.
- (a) Design of formwork shall consider (1) through (6):
- Method of concrete placement.
- Rate of concrete placement.
- Construction loads, including vertical, horizontal, and impact.
- Avoidance of damage to previously constructed members.
- For post-tensioned members, allowance for movement of the member during tensioning of the prestressing reinforcement without damage to the member.
- For post-tensioned members, allowance for load redistribution on formwork resulting from tensioning of the prestressing reinforcement.
- Formwork fabrication and installation shall result in a final structure that conforms to shapes, lines, and dimensions of the members as required by the construction documents.
- Formwork shall be sufficiently tight to inhibit leakage of paste or mortar.
- Formwork shall be braced or tied together to maintain position and shape.
- Before starting construction, the contractor shall develop a procedure and schedule for removal of formwork and installation of reshores, and shall calculate the loads transferred to the structure during this process.
- Structural analysis and concrete strength requirements used in planning and implementing the formwork removal and reshore installation shall be furnished by the contractor to the licensed design professional and to the building official, when requested.
- No construction loads shall be placed on, nor any formwork removed from, any part of the structure under construction except when that portion of the structure in combination with remaining formwork has sufficient strength to support safely its weight and loads placed thereon and without impairing serviceability.
- Sufficient strength shall be demonstrated by structural analysis considering anticipated loads, strength of formwork, and an estimate of in-place concrete strength.
- The estimate of in-place concrete strength shall be based on tests of field-cured cylinders or on other procedures to evaluate concrete strength approved by the licensed design professional and, when requested, approved by the building official.
- Formwork shall be removed in such a manner not to impair safety and serviceability of the structure.
- Concrete exposed by formwork removal shall have sufficient strength not to be damaged by the removal.
- Formwork supports for post-tensioned members shall not be removed until sufficient post-tensioning has been applied to enable post-tensioned members to support their dead load and anticipated construction loads.
- No construction loads exceeding the combination of superimposed dead load plus live load including reduction shall be placed on any unshored portion of the structure under construction, unless analysis indicates adequate strength to support such additional loads and without impairing serviceability.
- Evaluation of hardened concrete shall be based on strength tests. A strength test is the average of the compressive strengths of at least two 6 × 12 in. cylinders or at least three 4 × 8 in. cylinders made from the same sample of concrete taken in accordance with ASTM C172 at the point of delivery, handled and standard-cured in accordance with ASTM C31, and tested in accordance with ASTM C39 at 28 days or at test age designated for fc'.
- For shotcrete, a strength test shall be the average strength of at least three 3 in. nominal diameter cores taken from a test panel prepared in accordance with ASTM C1140 and tested at 28 days from time of placement or at test age designated for fc'.
- The testing agency performing acceptance testing shall comply with ASTM C1077.
- Certified field testing technicians shall perform tests on fresh concrete at the job site, prepare specimens for standard curing, prepare specimens for field curing, if required, and record the temperature of the fresh concrete when preparing specimens for strength tests.
- Certified laboratory technicians shall perform required laboratory tests.
- All reports of acceptance tests shall be provided to the licensed design professional, contractor, concrete producer, and, if requested, to the owner and the building official.
- Samples for preparing strength-test specimens of each concrete mixture placed each day shall be taken in accordance with (1) through (3):
- On a given project, if total volume of concrete is such that frequency of testing would provide fewer than five strength tests for a given concrete mixture, strength test specimens shall be made from at least five randomly selected batches or from each batch if fewer than five batches are used.
- If the total quantity of a given concrete mixture is less than 50 yd3, strength tests are not required if evidence of satisfactory strength is submitted to and approved by the building official.
- For shotcrete, prepare a shotcrete test panel for each mixture and each nozzle operator at least once per day or for every 50 yd3 placed, whichever results in the greater number of panels.
- Strength level of a concrete mixture shall be acceptable if (1) and (2) are satisfied:
- If either of the requirements of 188.8.131.52(a) is not satisfied, steps shall be taken to increase subsequent strength tests.
- Requirements of 26.12.6 for investigating strength tests shall apply if the requirements of 184.108.40.206(a)(2) are not met.
- Specimens for acceptance tests shall be in accordance with (1) and (2):
- Test panels shall be prepared in the same orientation and by the same nozzle operator placing shotcrete.
- Cores shall be obtained, conditioned, and tested in accordance with ASTM C1604.
- Strength of a shotcrete mixture shall be acceptable if the average compressive strength of three cores from a single test panel is not less than 0.85fc' with no core having a strength less than 0.75fc'.
- If the requirements of 220.127.116.11(b) is not satisfied, steps shall be taken to increase the average of subsequent strength results.
- Requirements for investigating low strength-test results shall apply if the requirement of 18.104.22.168(b) is not met.
- Frequency of sampling for determining fresh density shall be according to 26.12.2.
- Sampling of lightweight concrete for determining fresh density shall be at the point of delivery in accordance with ASTM C172.
- Fresh density of lightweight concrete shall be determined in accordance with ASTM C138.
- Unless otherwise permitted by the licensed design professional, fresh density of lightweight concrete shall be acceptable if within ±4.0 lb/ft3 of the fresh density corresponding to the specified equilibrium density.
- If any strength test of standard-cured cylinders falls below fc' by more than the limit allowed for acceptance, or if tests of field-cured cylinders indicate deficiencies in protection and curing, steps shall be taken to ensure that structural adequacy of the structure is not jeopardized.
- If the likelihood of low-strength concrete is confirmed and calculations indicate that structural adequacy is significantly reduced, tests of cores drilled from the area in question in accordance with ASTM C42 shall be permitted. In such cases, three cores shall be taken for each strength test that falls below fc' by more than the limit allowed for acceptance.
- The licensed design professional or the building official shall be permitted to modify details of core tests as stated in ASTM C42.
- Cores shall be obtained, moisture-conditioned by storage in watertight bags or containers, transported to the testing agency, and tested in accordance with ASTM C42. Cores shall be tested between 5 days after last being wetted and 7 days after coring unless otherwise approved by the licensed design professional or building official.
- Concrete in an area represented by core tests shall be considered structurally adequate if (1) and (2) are satisfied:
- Additional testing of cores extracted from locations represented by erratic core strength results shall be permitted.
- If criteria for evaluating structural adequacy based on core strength results are not met, and if the structural adequacy remains in doubt, the responsible authority shall be permitted to order a strength evaluation in accordance with Chapter 27 for the questionable portion of the structure or take other appropriate action.
- Steel fiber-reinforced concrete used for shear resistance shall satisfy (1) through (3):
- The compressive strength acceptance criteria for standard-cured specimens
- The residual strength obtained from flexural testing in accordance with ASTM C1609 at a midspan deflection of 1/300 of the span length is at least the greater of (i) and (ii):
- 90 percent of the measured first-peak strength obtained from a flexural test and
- 90 percent of the strength corresponding to
- The residual strength obtained from flexural testing in accordance with ASTM C1609 at a midspan deflection of 1/150 of the span length is at least the greater of (i) and (ii):
- 75 percent of the measured first-peak strength obtained from a flexural test and
- 75 percent of the strength corresponding to
Concrete construction shall be inspected as required by the general building code, and as a minimum, the inspection shall comply with the requirements provided in 26.13. In the absence of a general building code, concrete construction shall be inspected in accordance with the provisions of this Code.
Inspection of concrete construction shall be conducted by the licensed design professional responsible for the design, a person under the supervision of the licensed design professional, or a qualified inspector. The inspection shall verify conformance with construction documents throughout the various Work stages. If an inspector conducts inspection of formwork, concrete placement, reinforcement, and embedments, the inspector shall be certified.
Inspection of concrete placement and reinforcement for special moment frames, boundary elements of special structural walls, coupling beams, and precast concrete diaphragms assigned to SDC C, D, E, or F using moderate or high-deformability connections, shall be performed under the supervision of the licensed design professional responsible for the design, by a person under the supervision of a licensed design professional with demonstrated capability to supervise inspection of these elements or by a certified inspector. Installation tolerances of precast concrete diaphragm connections shall be inspected for compliance with ACI 550.5.
Inspection of the installation of post-installed expansion (torque-controlled and displacement-controlled), screw, and undercut anchors shall be performed by a certified inspector or a qualified inspector specifically approved for that purpose by the Licensed Design Professional and the building official.
Inspection reports shall document (a) through (e):
- General progress of the Work.
- Any significant construction loadings on completed floors, members, or walls.
- The date and time of mixing, quantity of concrete placed, identification of mixtures used, approximate placement location in the structure, and results of tests for fresh and hardened concrete properties for all concrete mixtures used in the Work.
- Concrete temperatures and protection given to concrete during placement and curing if the ambient temperature falls below 40°F or rises above 95°F.
- Placement of reinforcement and tensioning of prestressing reinforcement including measurement and recording of tendon elongation and force from a calibrated gauge.
Test reports shall be verified to confirm weldability of reinforcement other than ASTM A706, if weldability is required.
For post-installed expansion (torque-controlled and displacement-controlled), screw, and undercut anchors and adhesive anchors, materials, and installation procedures shall be verified for conformance with the approved construction documents and the manufacturer's recommended procedures, which are the Manufacturer's Printed Installation Instructions (MPII) in the case of adhesive anchors. Confirm procedures and results of proof loading where required in accordance with 26.7.1(k).
Items requiring verification and continuous inspection shall include (a) through (e):
- Prior to placement, concrete mixture for intended location.
- Tensioning of prestressing reinforcement and grouting of bonded tendons.
- Placement of reinforcement for special moment frames, boundary elements of special structural walls, and coupling beams.
- Welding of reinforcement for special moment frames, boundary elements of special structural walls, and coupling beams.
- Post-installed anchor installation, if required as a condition of the anchor assessment or if adhesive anchors are installed in horizontal or upwardly inclined orientations to resist sustained tensile loads.
Items requiring verification and periodic inspection shall include (a) through (j):
- Placement of reinforcement, embedments, and post-tensioning tendons.
- Welding of reinforcement except as required in 22.214.171.124(d).
- Curing method and duration of curing for each member.
- Construction and removal of forms and reshoring.
- Sequence of erection and connection of precast members.
- Verification of in-place strength of concrete before stressing post-tensioned tendons and before removal of shores and formwork from beams and structural slabs.
- Placement of cast-in-anchors and anchor reinforcement, including tolerances required for location of anchor reinforcement.
- Installation of post-installed expansion (torque-controlled and displacement-controlled) screw, and undercut anchors.
- Installation of adhesive anchors, except as required in 126.96.36.199(e).
- Proof loading of anchors if required in accordance with 188.8.131.52.