MINIMUM SPECIFIED COMPRESSIVE STRENGTH (f ′c)
|TYPE OR LOCATION OF CONCRETE CONSTRUCTION||MINIMUM SPECIFIED COMPRESSIVE STRENGTH (f ′c at 28 days, psi)|
|Negligible exposure||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|
|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 ACI 318.|
|c. Structural plain concrete basement walls are exempt from the requirements for exposure conditions of Section 1904.2.|
|d. For garage floor slabs where a steel trowel finish is used, the total air content required by ACI 318 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.|
WEATHERING PROBABILITY MAP FOR CONCRETEa, b, c
|a. Lines defining areas are approximate only. Local areas can be more or less severe than indicated by the region classification.|
|b. A “severe” classification is where weather conditions encourage or require the use of deicing chemicals or where there is potential for a continuous presence of moisture during frequent cycles of freezing and thawing. A “moderate” classification is where weather conditions occasionally expose concrete in the presence of moisture to freezing and thawing, but where deicing chemicals are not generally used. A “negligible” classification is where weather conditions rarely expose concrete in the presence of moisture to freezing and thawing.|
|c. Alaska and Hawaii are classified as severe and negligible, respectively.|
184.108.40.206 - 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, D, E or F also shall satisfy 220.127.116.11 through 18.104.22.168, as applicable. Except for structural elements of plain concrete complying with Section 1905.1.8 of the International Building Code, structural elements of plain concrete are prohibited in structures assigned to Seismic Design Category C, D, E or F.
22.214.171.124 - Structural systems designated as part of the seismic force-resisting system shall be restricted to those permitted by ASCE 7. 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:
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, E or F shall comply with Section 1905.1.4 of the International 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).
21.4.7 - Wall segments with a horizontal length-to-thickness ratio less than 2.5 shall be designed as columns.
21.9.8 - Wall piers and wall segments.
126.96.36.199 - Wall piers not designed as a part of a special moment frame shall have transverse reinforcement designed to satisfy the requirements in 188.8.131.52.
184.108.40.206 - Transverse reinforcement with seismic hooks at both ends shall be designed to resist the shear forces determined from 220.127.116.11. 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).
18.104.22.168 - Wall segments with a horizontal length-to-thickness ratio less than 2.5 shall be designed as columns.
21.10.2 - Special structural walls constructed using precast concrete shall satisfy all the requirements of 21.9 for cast-in-place special structural walls in addition to Sections 21.4.2 through 21.4.4.
22.214.171.124 - Foundations resisting earthquake-induced forces or transferring earthquake-induced forces between a structure and ground shall comply with the requirements of Section 21.12 and other applicable provisions of ACI 318 unless modified by Chapter 18 of the International Building Code.
22.6.7 - Detailed plain concrete structural walls.
126.96.36.199 - Detailed plain concrete structural walls are walls conforming to the requirements of ordinary structural plain concrete walls and 188.8.131.52.
184.108.40.206 - Reinforcement shall be provided as follows:
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:
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.
D.3.3.4 - Anchors shall be designed to be governed by the steel strength of a ductile steel element as determined in accordance with D.5.1 and D.6.1, unless either D.3.3.5 or D.3.3.6 is satisfied.
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.
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 force level corresponding to anchor forces no greater than the design strength of anchors specified in D.3.3.3.
D.3.3.6 - As an alternative to D.3.3.4 and D.3.3.5, it shall be permitted to take the design strength of the anchors as 0.4 times the design strength determined in accordance with D.3.3.3.
D.3.3.7 – 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 of sill plate or track to foundation or foundation stem wall need not satisfy D.3.3.6 when the design strength of the anchors is determined in accordance with D.6.2.1(c).
D.4.2.2 - The concrete breakout strength requirements for anchors in tension shall be considered satisfied by the design procedure of D.5.2 provided Equation D-7 is not used for anchor embedments exceeding 25 inches. The concrete breakout strength requirements for anchors in shear with diameters not exceeding 2 inches shall be considered satisfied by the design procedure of D.6.2. For anchors in shear with diameters exceeding 2 inches, shear anchor reinforcement shall be provided in accordance with the procedures of D.6.2.9.
|(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 1908.2, pounds (N).|
|Vs||=||Applied shear service load, pounds (N).|
|Vt||=||Allowable shear service load from Table 1908.2, pounds (N).|
ALLOWABLE SERVICE LOAD ON EMBEDDED BOLTS (pounds)
|MINIMUM CONCRETE STRENGTH (psi)|
|f ′c = 2,500||f ′c = 3,000||f ′c = 4,000|
|For SI: 1 inch = 25.4 mm, 1 pound per square inch = 0.00689 MPa, 1 pound = 4.45 N.|
Exception: Subject to the approval of the building 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.