- Specified compressive strength of concrete at the stated ages or stages of construction for which each concrete element is designed.
- Specified strength or grade of reinforcement.
- Size and location of structural elements, reinforcement, and anchors.
- Provision for dimensional changes resulting from creep, shrinkage and temperature.
- Magnitude and location of prestressing forces.
- Anchorage length of reinforcement and location and length of lap splices.
- Type and location of mechanical and welded splices of reinforcement.
- Details and location of contraction or isolation joints specified for plain concrete.
- Minimum concrete compressive strength at time of posttensioning.
- Stressing sequence for posttensioning tendons.
- For structures assigned to Seismic Design Category D, a statement if slab on grade is designed as a structural diaphragm (see Section 2112.3.4 of ACI 318).
- Exposure classes per Section 1904.2 of this chapter and Section 4.2 of ACI 318.
- Areas of mass-concrete where a thermal control plan is required.
MASS CONCRETE. Any volume of concrete with dimensions large enough to require that measures be taken to cope with generation of heat from hydration of the cement and attendant volume change to minimize cracking, reduction of compressive strength, and/or delayed ettringite formation.
- Exposure to freezing and thawing in a moist condition or exposure to deicing chemicals;
- Exposure to sulfates in water or soil;
- Exposure to water where the concrete is intended to have low permeability; and
- Exposure to chlorides from deicing chemicals, salt, saltwater, brackish water, seawater or spray from these sources, where the concrete has steel reinforcement.
Exception: For occupancies and appurtenances thereto in Group R occupancies that are in buildings less than four stories above grade plane, normal-weight aggregate concrete is permitted to comply with the requirements of Table 1904.3 of this chapter in lieu of the requirements of ACI 318, Table 4.3.1.
TABLE 1904.3 MINIMUM SPECIFIED COMPRESSIVE STRENGTH (f 'c)
|TYPE OR LOCATION OF CONCRETE CONSTRUCTION|| MINIMUM SPECIFIED COMPRESSIVE |
STRENGTH (f 'c at 28 days, psi)
| Basement walls, foundation walls, exterior walls and other vertical concrete surfaces, basement slabs, |
interior slabs on grade except for garage floor slabs, and foundations not exposed to the weather
| Driveways, curbs, walks, patios, porches, carport slabs, steps and |
other flatwork exposed to the weather, and garage floor slabs
|Structural concrete exposed to weather||4,500|
|For SI: 1 pound per square inch = 0.00689 MPa.|
|a. Concrete in these locations that can be subjected to freezing and thawing during construction shall be of air-entrained concrete in accordance with Section 1904.2.|
|b. Concrete shall be air entrained in accordance with Section 1904.4.1.|
TABLE 1904.4.2 REQUIREMENTS FOR CONCRETE EXPOSED TO DEICING CHEMICALS
|CEMENTITIOUS MATERIALS|| MAXIMUM PERCENT OF |
|Fly ash or other pozzolans conforming to ASTM C 618||25d|
|Slag conforming to ASTM C 989||50|
|Silica fume conforming to ASTM C 1240||10|
|Total of fly ash or other pozzolans, slag and silica fume||50c|
|Total of fly ash or other pozzolans and silica fume||35c|
|a. The total cementitious material also includes ASTM C 150, ASTM C 595, ASTM C 845 and ASTM C 1157 cement.|
|b. The maximum percentages shall include:|
|1. Fly ash or other pozzolans present in Type IP or I (PM) blended cement, ASTM C 595, or ASTM C 1157.|
|2. Slag used in the manufacture of an IS or I (SM) blended cement, ASTM C 595, or ASTM C 1157.|
|3. Silica fume, ASTM C 1240, present in a blended cement.|
|c. Fly ash or other pozzolans and silica fume shall constitute no more than 25 and 10 percent, respectively, of the total weight of the cementitious materials. The amount of fly ash or other pozzolans conforming to ASTM C 618 shall be permitted to be increased in accordance with footnote d, provided the maximum percentage of supplemental cementitious materials does not exceed the maximum values stated in Table 1904.4.2 when combining multiple types of supplemental cementitious materials.|
|d. Amount of fly ash or other pozzolans conforming to ASTM C 618 in a given concrete mixture can be increased to 35% provided that the concrete is not placed during cold weather as defined by ACI 306 or that the concrete is membrane cured and protected from freezing until the concrete has attained 3,500 psi.|
- Workability and consistency to permit concrete to be worked readily into forms and around reinforcement under the conditions of placement to be employed, without segregation or excessive bleeding.
- Resistance to special exposures as required by Section 1904.
- Conformance with the strength test requirements of Section 1905.6.
- Cementitious materials. Cementitious materials shall be used in the same quantities for each individual component and shall be of the same type and shall be from the same source and mill. Upon request, the concrete producer shall provide mill certificates for the cementitious materials proposed for use and cementitious materials represented by the field strength test records or trial mixtures to the registered design professional of record and the department.
- Aggregates. Coarse and fine aggregates shall be the same nominal maximum size and shall be used in the same volume for each individual component.
- Admixtures. Admixtures shall meet the requirements of the same admixture type in accordance with ASTM C 494 or ASTM C 260 and there shall be no change in air content or water content from the previously specified mix.
Exception: Addition or removal of retarding or accelerating admixtures as described in Section 1905.3.5 is acceptable.
- Additional testing. Differences or changes in materials that are proposed for use, not meeting the requirements of Items 1 through 3 above, shall require new testing demonstrated by either field strength test records or trial mixtures.
- There are no changes to the type and source of materials described in Section 1905.3.4;
- Documentation of these changes are maintained by the concrete producer and the concrete contractor;
- The changes described in Section 1905.3.5 cannot be used for the submission of an initial mix design to demonstrate that a previously prepared mix design meets strength or air content requirements that differ from the required concrete properties without new field strength test records or new trial mix designs;
- Where required in Section 1905.3.5, documentation of these changes shall be submitted for acceptance to the registered design professional of record for the structural design by the concrete producer prior to use;
- Copies of the revised mixtures shall be maintained at the construction site and provided to the licensed concrete testing laboratory performing the acceptance testing of concrete in accordance with Item 4 of Table 1704.4 of this code; and
- The documentation required by Items 2 and 5 above shall be made available to the commissioner upon request.
1905.3.5.1 Changes That Do Not Require Prior Approval of the Registered Design Professional of Record for the Structure
- Air-entraining admixtures. Air-entraining admixture dosages can be increased or decreased as needed to obtain the air content specified in the construction documents.
- Water reducing admixtures. Water reducing admixture dosages can be increased or decreased to produce the specified workability, provided that the design water is not exceeded and the changes do not segregate the concrete mix.
1905.3.5.2 Changes That Require Prior Approval of the Registered Design Professional of Record for the Structure
- Retarding and accelerating admixtures. Retarding and accelerating admixtures may be added to concrete mixtures or the dosage may be modified as needed to maintain practical set times.
- Pigment. Pigment dosage may be adjusted to maintain uniform concrete color.
- Fibers. Synthetic, glass or natural fibers may be added to the mix within the manufacturer recommended range. Any loss in workability shall be compensated with a water reducer.
Exception: Steel fibers may not be added to a concrete mixture without the performance of a new mix design.
- Corrosion inhibitor. Corrosion inhibiting admixtures may be added, provided the corresponding adjustment of mix water remains within the limits of the required water/cementitious material ratio. The added materials and the revised design mix shall be submitted for review by the registered design professional of record for the structure prior to use.
- Cementitious content and water-cementitous material ratio (w/cm). The cementitious content may be increased by a maximum of 12 percent, or the w/cm ratio may be decreased while maintaining the same cementitious content, but the w/cm and air content shall not be increased. Aggregate quantities shall be adjusted, as required, to maintain the mix proportion and yield.
- Every arithmetic average of any three consecutive strength tests equals or exceeds f'c.
- No individual strength test (average of two cylinders) falls below f'c by more than 500 psi (3.45 MPa) when f'c is 5,000 psi (34.50 MPa) or less, or by more than 0.10 f'c when f'c is more than 5,000 psi (34.50 MPa).
- Temperature in accordance with ASTM C 1064.
- Slump in accordance with ASTM C 143.
- Unit weight in accordance with ASTM C 138.
- Air content in accordance with ASTM C 173 or C 231. Testing in accordance with ASTM C 173 must be used for concretes made with lightweight aggregates, and other instances where ASTM C 231 is not applicable.
- Water content per AASHTO T 318 when required by 1905.6.2.1.
- Equipment for mixing and transporting concrete shall be clean.
- Debris and ice shall be removed from spaces to be occupied by concrete.
- Forms shall be properly coated.
- Masonry filler units that will be in contact with concrete shall be well drenched.
- Reinforcement shall be thoroughly clean of ice or other deleterious coatings.
- Water shall be removed from the place of deposit before concrete is placed unless a tremie is to be used or unless otherwise permitted by the commissioner.
- Laitance and other unsound material shall be removed before additional concrete is placed against hardened concrete.
- Plant name and location.
- Contract number and project.
- Mix designation as to type and strength.
- Each material in the load along with quantities of each by weight.
- The total amount of mix proportion water approved, quantity of water added at the plant and in transit, and the remaining water that can be added on site.
- Any deviations from the approved concrete mix design and variations permitted by Section 1905.3.5.
- The time the water was added to the batch.
- Adequate equipment shall be provided for insulating or heating concrete materials and protecting concrete during freezing or near-freezing weather.
- Concrete materials and reinforcement, forms, fillers and ground with which concrete is to in contact shall be free from frost. The temperature of surfaces in contact with fresh concrete, including but not limited to forms and reinforcing steel, shall be raised above freezing.
- Frozen materials or materials containing ice shall not be used.
TABLE 1907.5.2.1 TOLERANCES
|DEPTH (d) (inches)||TOLERANCE ON d (inch)||TOLERANCE ON SPECIFIED CONCRETE COVER|
|d ≤ 8||± 3/8||- 3/8|
|d > 8||± 1/2||- 1/2|
TABLE 1907.7.1 MINIMUM CONCRETE COVER
|CONCRETE EXPOSURE|| MINIMUM |
|1.|| Concrete cast against and permanently |
exposed to earth
|2.||Concrete exposed to earth or weather|
|No. 6 through No. 18 bar||2|
|No. 5 bar, W31 or D31 wire, and smaller||11/2|
|3.|| Concrete not exposed to weather or in contact |
|Slabs, walls, joists:|
|No. 14 and No. 18 bars||11/2|
|No. 11 bar and smaller||3/4|
|Primary reinforcement, ties, stirrups, spirals||11/2|
|Shells, folded plate members:|
|No. 6 bar and larger||3/4|
|No. 5 bar, W31 or D31 wire, and smaller||1/2|
DESIGN DISPLACEMENT. Total lateral displacement expected for the design-basis earthquake, as specified by Section 12.8.6 of ASCE 7.
DETAILED PLAIN CONCRETE STRUCTURAL WALL. A wall complying with the requirements of Chapter 22, including 22.6.7.
ORDINARY PRECAST STRUCTURAL WALL. A precast wall complying with the requirements of Chapters 1 through 18.
ORDINARY REINFORCED CONCRETE STRUCTURAL WALL. A cast-in-place wall complying with the requirements of Chapters 1 through 18.
ORDINARY STRUCTURAL PLAIN CONCRETE WALL. A wall complying with the requirements of Chapter 22, excluding 22.6.7.
SPECIAL STRUCTURAL WALL. A cast-in-place or precast wall complying with the requirements of 21.1.3 through 21.1.7, 21.9 and 21.10, as applicable, in addition to the requirements for ordinary reinforced concrete structural walls or ordinary precast structural walls, as applicable. Where ASCE 7 refers to a "special reinforced concrete structural wall," it shall be deemed to mean a "special structural wall."
WALL PIER. A wall segment with a horizontal length-to-thickness ratio of at least 2.5, but not exceeding six, whose clear height is at least two times its horizontal length.
220.127.116.11 — Structures assigned to Seismic Design Category A shall satisfy requirements of Chapters 1 to 19 and 22; Chapter 21 does not apply. Structures assigned to Seismic Design Category B, C, or D also shall satisfy 18.104.22.168 through 22.214.171.124, as applicable. Except for structural elements of plain concrete complying with Section 1908.1.8 of the New York City Building Code, structural elements of plain concrete are prohibited in structures assigned to Seismic Design Category C or D.
126.96.36.199 — Structural systems designated as part of the seismic-force-resisting system shall be restricted to those permitted by ASCE 7 as modified by Chapter 16 of the New York City Building Code. Except for Seismic Design Category A, for which Chapter 21 does not apply, the following provisions shall be satisfied for each structural system designated as part of the seismic-force-resisting system, regardless of the Seismic Design Category:
(a) Ordinary moment frames shall satisfy 21.2.
(b) Ordinary reinforced concrete structural walls and ordinary precast structural walls need not satisfy any provisions in Chapter 21.
(c) Intermediate moment frames shall satisfy 21.3.
(d) Intermediate precast structural walls shall satisfy 21.4.
(e) Special moment frames shall satisfy 21.5 through 21.8.
(f) Special structural walls shall satisfy 21.9.
(g) Special structural walls constructed using precast concrete shall satisfy 21.10.
All special moment frames and special structural walls shall also satisfy 21.1.3 through 21.1.7.
21.4.3 — Connections that are designed to yield shall be capable of maintaining 80 percent of their design strength at the deformation induced by the design displacement or shall use Type 2 mechanical splices.
21.4.4 — Elements of the connection that are not designed to yield shall develop at least 1.5 Sy.
21.4.5 — Wall piers in Seismic Design Category D shall comply with section 1908.1.4 of the New York City Building Code.
21.4.6 — Wall piers not designed as part of a moment frame in buildings assigned to Seismic Design Category C shall have transverse reinforcement designed to resist the shear forces determined from 21.3.3. Spacing of transverse reinforcement shall not exceed 8 inches (203 mm). Transverse reinforcement shall be extended beyond the pier clear height for at least 12 inches (305 mm).
- Wall piers that satisfy 21.13.
- Wall piers along a wall line within a story where other shear wall segments provide lateral support to the wall piers and such segments have a total stiffness of at least six times the sum of the stiffnesses of all the wall piers.
21.9.8 Wall piers and wall segments.
188.8.131.52 Wall piers not designed as a part of a special moment frame shall have transverse reinforcement designed to satisfy the requirements in Section 184.108.40.206.
- Wall piers that satisfy Section 21.13.
- Wall piers along a wall line within a story where other shear wall segments provide lateral support to the wall piers, and such segments have a total stiffness of at least six times the sum of the stiffnesses of all the wall piers.
220.127.116.11 Wall segments with a horizontal length-to-thickness ratio less than 2.5 shall be designed as columns.
18.104.22.168 Foundations resisting earthquake-induced forces or transferring earthquake-induced forces between a structure and the ground shall comply with the requirements of Section 21.10 and other applicable provisions of ACI 318 unless modified by Chapter 18 of the New York City Building Code.
22.6.7 — Detailed plain concrete structural walls.
22.214.171.124 — Detailed plain concrete structural walls are walls conforming to the requirements of ordinary structural plain concrete walls and 126.96.36.199.
188.8.131.52 — Reinforcement shall be provided as follows:
(a) Vertical reinforcement of at least 0.20 square inch (129 mm2) in cross-sectional area shall be provided continuously from support to support at each corner, at each side of each opening and at the ends of walls. The continuous vertical bar required beside an opening is permitted to substitute for one of the two No. 5 bars required by 184.108.40.206.
(b) Horizontal reinforcement at least 0.20 square inch (129 mm2) in cross-sectional area shall be provided:
- Continuously at structurally connected roof and floor levels and at the top of walls;
- At the bottom of load-bearing walls or in the top of foundations where doweled to the wall; and
- At a maximum spacing of 120 inches (3048 mm).
22.10 — Plain concrete in structures assigned to Seismic Design Category C or D.
22.10.1 — Structures assigned to Seismic Design Category C or D shall not have elements of structural plain concrete, except as follows:
(a) Structural plain concrete basement, foundation or other walls below the base are permitted in detached one- and two-family dwellings three stories or less in height constructed with stud-bearing walls. In dwellings assigned to Seismic Design Category D, the height of the wall shall not exceed 8 feet (2438 mm), the thickness shall not be less than 71/2 inches (190 mm), and the wall shall retain no more than 4 feet (1219 mm) of unbalanced fill. Walls shall have reinforcement in accordance with 220.127.116.11.
(b) Isolated footings of plain concrete supporting pedestals or columns are permitted, provided the projection of the footing beyond the face of the supported member does not exceed the footing thickness.
Exception: In detached one- and two-family dwellings three stories or less in height, the projection of the footing beyond the face of the supported member is permitted to exceed the footing thickness.
(c) Plain concrete footings supporting walls are permitted, provided the footings have at least two continuous longitudinal reinforcing bars. Bars shall not be smaller than No. 4 and shall have a total area of not less than 0.002 times the gross cross-sectional area of the footing. For footings that exceed 8 inches (203 mm) in thickness, a minimum of one bar shall be provided at the top and bottom of the footing. Continuity of reinforcement shall be provided at corners and intersections.
- In Seismic Design Categories A, B and C, detached one- and two-family dwellings three stories or less in height and constructed with stud-bearing walls are permitted to have plain concrete footings without longitudinal reinforcement.
- For foundation systems consisting of a plain concrete footing and a plain concrete stemwall, a minimum of one bar shall be provided at the top of the stem wall and at the bottom of the footing.
- Where a slab on ground is cast monolithically with the footing, one No. 5 bar is permitted to be located at either the top of the slab or bottom of the footing.
D.18.104.22.168 - Where the tensile component of the strength-level earthquake force applied to anchors exceeds 20 percent of the total factored anchor tensile force associated with the same load combination, anchors and their attachments shall be designed in accordance with Section D.22.214.171.124. The anchor design tensile strength shall be determined in accordance with Section D.126.96.36.199.
D.188.8.131.52(d) — The anchor or group of anchors shall be designed for the maximum tension obtained from design load combinations that include E, with E increased by Ω0. The anchor design tensile strength shall be calculated from Section D.184.108.40.206.
D.220.127.116.11 — Where the shear component of the strength-level earthquake force applied to anchors exceeds 20 percent of the total factored anchor shear force associated with the same load combination, anchors and their attachments shall be designed in accordance with D.18.104.22.168. The anchor design shear strength for resisting earthquake forces shall be determined in accordance with Section D.6.
- For the calculation of the in-plane shear strength of anchor bolts attaching wood sill plates of bearing or nonbearing walls of light-frame wood structures to foundations or foundation stem walls, the in-plane shear strength in accordance with Sections D.6.2 and D.6.3 need not be computed and Section D.22.214.171.124 shall be deemed to be satisfied provided all of the following are met:
- The allowable in-plane shear strength of the anchor is determined in accordance with AF&PA NDS Table 11E for lateral design values parallel to grain.
- The maximum anchor nominal diameter is 5/8 inches (16 mm).
- Anchor bolts are embedded into concrete a minimum of 7 inches (178 mm).
- Anchor bolts are located a minimum of 13/4 inches (45 mm) from the edge of the concrete parallel to the length of the wood sill plate.
- Anchor bolts are located a minimum of 15 anchor diameters from the edge of the concrete perpendicular to the length of the wood sill plate.
- The sill plate is of 2-inch or 3-inch nominal thickness.
- For the calculation of the in-plane shear strength of anchor bolts attaching cold-formed steel track of bearing or nonbearing walls of light-frame construction to foundations or foundation stem walls, the in-plane shear strength in accordance with Sections D.6.2 and D.6.3 need not be computed and Section D.126.96.36.199 shall be deemed to be satisfied provided all of the following are met:
- The maximum anchor nominal diameter is 5/8 inches (16 mm).
- Anchors are embedded into concrete a minimum of 7 inches (178 mm).
- Anchors are located a minimum of 13/4 inches (45 mm) from the edge of the concrete parallel to the length of the track.
- Anchors are located a minimum of 15 anchor diameters from the edge of the concrete perpendicular to the length of the track.
- The track is 33 to 68 mil designation thickness. Allowable in-plane shear strength of exempt anchors, parallel to the edge of concrete shall be permitted to be determined in accordance with AISI S100 Section E3.3.1.
- In light-frame construction, bearing or non-bearing walls, shear strength of concrete anchors less than or equal to 1 inch (25 mm) in diameter connecting sill plate or track to foundation or foundation stem wall need not satisfy Section D.188.8.131.52(a) through (c) when the design strength of the anchors is determined in accordance with Section D.6.2.1(c).
10.12.4 When the specified compressive strength of concrete in a column is greater than 1.4 times that specified for a floor system, the following additional requirements shall be adhered to:
- All of the design provisions of Section 10.12 (unmodified) are adhered to.
- The concrete construction is supervised and inspected continuously by a full-time professional engineer responsible for the concrete placement special inspection. Such professional engineer shall not delegate this responsibility to any subordinates.
Exception: For Group R-3 occupancies and buildings of other occupancies less than two stories above grade plane of light-frame construction, the required edge thickness of ACI 318 is permitted to be reduced to 6 inches (152 mm), provided that the footing does not extend more than 4 inches (102 mm) on either side of the supported wall.
Exception: A vapor retarder is not required:
- For detached structures accessory to occupancies in Group R-3, such as garages, utility buildings or other unheated facilities.
- For unheated storage rooms having an area of less than 70 square feet (6.5 m2) and carports attached to occupancies in Group R-3.
- For buildings of other occupancies where migration of moisture through the slab from below will not be detrimental to the intended occupancy of the building.
- For drive ways, walks, patios and other flat work that will not be enclosed at a later date.
- Where approved based on local site conditions.
|Ps||=||Applied tension service load, pounds (N).|
|Pt||=||Allowable tension service load from Table 1911.2, pounds (N).|
|Vs||=||Applied shear service load, pounds (N).|
|Vt||=||Allowable shear service load from Table 1911.2, pounds (N).|
TABLE 1911.2 ALLOWABLE SERVICE LOAD ON EMBEDDED BOLTS (pounds)
| BOLT |
| MINIMUM |
| EDGE |
| SPACING |
|MINIMUM CONCRETE STRENGTH (psi)|
|f'c = 2,500||f'c = 3,000||f'c = 4,000|
Exception: Subject to the approval of the commissioner, required clearances shall be reduced where it is demonstrated by preconstruction tests that adequate encasement of the bars used in the design will be achieved.
- Three specimens with no reinforcing shall be sampled and prepared in accordance with ASTM C 42; and
- Three specimens with reinforcing steel.
Exception: Flat plate middle strip bottom mat reinforcing perpendicular to discontinuous slab edges. In addition, the main bottom mat reinforcement in one-way slabs shall be anchored at discontinuous edges.
- Three times the load entering the column at that level, using a load combination of 1.0 × DL (self weight of structure only).
- One and a half times the load entering the column at that level using the load combinations of (1.2 DL + 1.6 LL) or 1.4 DL.
- For transfer elements only, in lieu of Item 1 or 2, the horizontal reinforcement shall be anchored at all supports.
ASPHALT. A dark brown to black bitumen pitch that melts readily and which appears in nature in asphalt beds or is produced as a by-product of the petroleum industry.
ASPHALTIC CONCRETE or ASPHALT PAVING. A mixture of liquid asphalt and graded aggregate used as a paving material.
I-4 MIX. A type of heavy duty asphaltic concrete mix containing 0.75 inch (19 mm) nominal maximum size aggregate with 25 percent to 50 percent of the aggregate capable of passing through a No. 8 sieve and in which all sand contained in the mix is crushed.
RECLAIMED ASPHALT PAVEMENT. Asphalt pavement that has been processed for reuse in asphaltic concrete.
- Asphaltic concrete used in a project where the content of asphaltic concrete is governed by a federal or state law, rule, regulation, guideline, or specification that requires a different composition.
- Asphaltic concrete used for runways, taxiways, or other surfaces utilized by aircraft.
- The commissioner may waive compliance with this section if the commissioner, after consulting with the commissioner of transportation and the owners or persons in charge of all asphalt plants located within the city, finds that a sufficient supply of reclaimed asphalt pavement is not available.