- The specified compressive strength of concrete at the stated ages or stages of construction for which each concrete element is designed.
- The specified strength or grade of reinforcement.
- The size and location of structural elements, reinforcement, and anchors.
- Provision for dimensional changes resulting from creep, shrinkage and temperature.
- The 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, E or F, a statement if slab on grade is designed as a structural diaphragm (see Section 126.96.36.199 of ACI 318).
- Concrete intended to have low permeability where exposed to water;
- Concrete exposed to freezing and thawing in a moist condition or deicer chemicals; or
- Concrete with reinforcement where the concrete is exposed to chlorides from deicing chemicals, salt, salt water, brackish water, seawater or spray from these sources.
Exception: For occupancies and appurtenances thereto in Group R occupancies that are in buildings less than four stories in height, normal-weight aggregate concrete shall comply with the requirements of Table 1904.2.2 based on the weathering classification (freezing and thawing) determined from Figure 1904.2.2.
In addition, concrete exposed to deicing chemicals shall conform to the limitations of Section 1904.2.3.
|TYPE OR LOCATION OF CONCRETE CONSTRUCTION||MINIMUM SPECIFIED COMPRESSIVE STRENGTH (f'c at 28 days, psi)|
| Negligible |
|Moderate exposure||Severe exposure|
|Basement wallsc and foundations not exposed to the weather||2,500||2,500||2,500a|
|Basement slabs and interior slabs on grade, except garage floor slabs||2,500||2,500||2,500a|
|Basement wallsc, foundation walls, exterior walls and other vertical concrete surfaces exposed to the weather||2,500||3,000b||3,000b|
|Driveways, curbs, walks, patios, porches, carport slabs, steps and other flatwork exposed to the weather, and garage floor slabs||2,500||3,000b, d||3,500b, d|
- Concrete in these locations that can be subjected to freezing and thawing during construction shall be of air-entrained concrete in accordance with Section 1904.2.1.
- Concrete shall be air entrained in accordance with Section 1904.2.1.
- Structural plain concrete basement walls are exempt from the requirements for exposure conditions of Section 1904.2.2 (see Section 1909.6.1).
- For garage floor slabs where a steel trowel finish is used, the total air content required by Section 1904.2.1 is permitted to be reduced to not less than 3 percent, provided the minimum specified compressive strength of the concrete is increased to 4,000 psi.
Exception: When the total volume of a given class of concrete is less than 50 cubic yards (38 m 3 ), strength tests are not required when evidence of satisfactory strength is submitted to and approved by the code enforcement official.
10.5.5 - In structures assigned to Seismic Design Category B, beams in ordinary moment frames forming part of the seismic-force-resisting system shall have at least two main flexural reinforcing bars continuously top and bottom throughout the beam and continuous through or developed within exterior columns or boundary elements.
11.11- Special provisions for columns.
11.11.3 - In structures assigned to Seismic Design Category B, columns of ordinary moment frames having a clear height-to-maximum-plan-dimension ratio of five or less shall be designed for shear in accordance with 21.12.3.
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 .
WALL PIER. A wall segment with a horizontal length-to-thickness ratio of at least 2.5, but not exceeding 6, whose clear height is at least two times its horizontal length.
188.8.131.52 - For structures assigned to Seismic Design Category A or B , provisions of Chapters 1 through 18 and 22 shall apply except as modified by the provisions of this chapter. Where the seismic design loads are computed using provisions for intermediate or special concrete systems, the requirements of Chapter 21 for intermediate or special systems, as applicable, shall be satisfied.
184.108.40.206 - For structures assigned to Seismic Design Category C , intermediate or special moment frames, intermediate precast structural walls or ordinary or special reinforced concrete structural walls shall be used to resist seismic forces induced by earthquake motions. Where the design seismic loads are computed using provisions for special concrete systems, the requirements of Chapter 21 for special systems, as applicable, shall be satisfied.
220.127.116.11 - For structures assigned to Seismic Design Category D, E or F , special moment frames, special reinforced concrete structural walls , diaphragms and trusses and foundations complying with 21.2 through 21.10 or intermediate precast structural walls complying with 21.13 shall be used to resist forces induced by earthquake motions. Members not proportioned to resist earthquake forces shall comply with 21.11.
21.2.5 - Reinforcement in members resisting earthquake-induced forces.
18.104.22.168 - Except as permitted in 22.214.171.124, reinforcement resisting earthquake-induced flexural and axial forces in frame members and in structural wall boundary elements shall comply with ASTM A 706. ASTM A 615, Grades 40 and 60 reinforcement, shall be permitted in these members if (a) the actual yield strength based on mill tests does not exceed the specified yield, fy , strength by more than 18,000 psi (124 MPa) [retests shall not exceed this value by more than an additional 3,000 psi (21 MPa)], and (b) the ratio of the actual tensile strength to the actual yield strength is not less than 1.25.
For computing shear strength, the value of fyt for transverse reinforcement, including spiral reinforcement, shall not exceed 60,000 psi (414 MPa).
126.96.36.199 - Prestressing steel shall be permitted in flexural members of frames, provided the average prestress, fpc , calculated for an area equal to the member's shortest cross-sectional dimension multiplied by the perpendicular dimension shall be the lesser of 700 psi (4.83 MPa) or f 'c / 6 at locations of nonlinear action where prestressing steel is used in members of frames.
21.2.9 - Anchorages for unbonded post-tensioning tendons resisting earthquake induced forces in structures assigned to Seismic Design Category C, D, E or F shall withstand, without failure, 50 cycles of loading ranging between 40 and 85 percent of the specified tensile strength of the prestressing steel.
188.8.131.52 - Unless the special moment frame is qualified for use through structural testing as required by 21.6.3, for flexural members prestressing steel shall not provide more than one-quarter of the strength for either positive or negative moment at the critical section in a plastic hinge location and shall be anchored at or beyond the exterior face of a joint.
21.7.10 - Wall piers and wall segments.
184.108.40.206 - Wall piers not designed as a part of a special moment frame shall have transverse reinforcement designed to satisfy the requirements in 220.127.116.11.
18.104.22.168 - Transverse reinforcement with seismic hooks at both ends shall be designed to resist the shear forces determined from 22.214.171.124. Spacing of transverse reinforcement shall not exceed 6 inches (152 mm). Transverse reinforcement shall be extended beyond the pier clear height for at least 12 inches (305 mm).
126.96.36.199 - Wall segments with a horizontal length-to-thickness ratio less than 2.5 shall be designed as columns.
188.8.131.52 - 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 Building Code of New York State .
184.108.40.206 - Members with factored gravity axial forces exceeding ( Agf 'c/ 10) shall satisfy 21.4.3, 220.127.116.11(c), 18.104.22.168 and 21.4.5. The maximum longitudinal spacing of ties shall be so for the full column height. Spacing , so , shall not exceed the smaller of six diameters of the smallest longitudinal bar enclosed and 6 inches (152 mm). Lap splices of longitudinal reinforcement in such members need not satisfy 22.214.171.124 in structures where the seismic-force-resisting system does not include special moment frames.
126.96.36.199 - Columns supporting reactions from discontinuous stiff members, such as walls, shall be designed for the special load combinations in Section 1605.4 of the Building Code of New York State and shall be provided with transverse reinforcement at the spacing, so, as defined in 188.8.131.52 over their full height beneath the level at which the discontinuity occurs. This transverse reinforcement shall be extended above and below the column as required in 184.108.40.206.
21.13.3 - Except for Type 2 mechanical splices, connection elements that are designed to yield shall be capable of maintaining 80 percent of their design strength at the deformation induced by the design displacement.
21.13.4 - Elements of the connection that are not designed to yield shall develop at least 1.5 Sy .
21.13.5 - Wall piers not designed as part of a moment frame shall have transverse reinforcement designed to resist the shear forces determined from 21.12.3. 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 21.11 .
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.
21.13.6 - Wall segments with a horizontal length-to-thickness ratio less than 2.5 shall be designed as columns.
22.6.7 - Detailed plain concrete structural walls.
220.127.116.11 - Detailed plain concrete structural walls are walls conforming to the requirements of ordinary structural plain concrete walls and 18.104.22.168.
22.214.171.124 - 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 126.96.36.199.
(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
3. At a maximum spacing of 120 inches (3048 mm).
Reinforcement at the top and bottom of openings, where used in determining the maximum spacing specified in Item 3 above, shall be continuous in the wall.
22.10 - Plain concrete in structures assigned to Seismic Design Category C, D, E or F.
22.10.1 - Structures assigned to Seismic Design Category C, D, E or F 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 or E, 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 188.8.131.52.
(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 detached one- and two-family dwellings three stories or less in height and constructed with stud-bearing walls, plain concrete footings without longitudinal reinforcement supporting walls are permitted.
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 stemwall 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.3.3.2 - In structures assigned to Seismic Design Category C, D, E or F, post-installed anchors for use under D.2.3 shall have passed the Simulated Seismic Tests of ACI 355.2.
D.3.3.3 - In structures assigned to Seismic Design Category C, D, E or F, the design strength of anchors shall be taken as 0.75 rNn and 0.75 rVn , where r is given in D.4.4 or D.4.5, and Nn and Vn are determined in accordance with D.4.1.
D.3.3.4 - In structures assigned to Seismic Design Category C, D, E or F, anchors shall be designed to be governed by tensile or shear strength of a ductile steel element, unless D.3.3.5 is satisfied.
D.3.3.5 - Instead of D.3.3.4, the attachment that the anchor is connecting to the structure shall be designed so that the attachment will undergo ductile yielding at a load level corresponding to anchor forces no greater than the design strength of anchors specified in D.3.3.3 , or the minimum design strength of the anchors shall be at least 2.5 times the factored forces transmitted by the attachment .
- Members that are continuously supported by soil, such as walls and footings, or by other structural members capable of providing continuous vertical support.
- Members for which arch action provides compression under all conditions of loading.
- Walls and pedestals.
The use of structural plain concrete columns and structural plain concrete footings on piles is not permitted. See Section 1908.1.15 for additional limitations on the use of structural plain concrete.
Exception: For Group R-3 occupancies and buildings of other occupancies less than two stories in height 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 driveways, walks, patios and other flatwork which will not be enclosed at a later date.
- Where approved based on local site conditions.
|(Ps / Pt)5/3 + (Vs / Vt)5/3 ≤ 1||(Equation 19-1)|
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: Where the basic concrete breakout strength in tension of a single anchor, Nb, is determined in accordance with Equation (D-7), the concrete breakout strength requirements of Section D.4.2.2 shall be considered satisfied by the design procedures of Sections D.5.2 and D.6.2 for anchors exceeding 2 inches (51 mm) in diameter or 25 inches (635 mm) tensile embedment depth.
The strength design of anchors that are not within the scope of Appendix D of ACI 318, and as amended above, shall be in accordance with an approved procedure.
Exception: Subject to the approval of the code enforcement official, 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.