// CODE SNIPPET
722.2.4 Concrete Columns
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Concrete columns shall comply with this section.
For SI: 1 inch = 25 mm.
TYPES OF CONCRETE | FIRE-RESISTANCE RATING (hours) | ||||
1 | 11/2 | 2a | 3a | 4b | |
Siliceous | 8 | 9 | 10 | 12 | 14 |
Carbonate | 8 | 9 | 10 | 11 | 12 |
Sand-lightweight | 8 | 81/2 | 9 | 101/2 | 12 |
For SI: 1 inch = 25 mm.
- The minimum dimension is permitted to be reduced to 8 inches for rectangular columns with two parallel sides not less than 36 inches in length.
- The minimum dimension is permitted to be reduced to 10 inches for rectangular columns with two parallel sides not less than 36 inches in length.
The minimum overall dimensions of reinforced concrete columns for fire-resistance ratings of 1 hour to 4 hours for exposure to fire on all sides shall comply with this section.
For columns made with concrete having a specified compressive strength, f 'c, of less than or equal to 12,000 psi (82.7 MPa), the minimum dimension shall comply with Table 722.2.4.
For columns made with concrete having a specified compressive strength, f 'c, greater than 12,000 psi (82.7 MPa), for fire-resistance ratings of 1 hour to 4 hours the minimum dimension shall be 24 inches (610 mm).
The minimum thickness of concrete cover to the main longitudinal reinforcement in columns, regardless of the type of aggregate used in the concrete and the specified compressive strength of concrete, f 'c, shall be not less than 1 inch (25 mm) times the number of hours of required fire-resistancefire resistance or 2 inches (51 mm), whichever is less.
For concrete columns made with concrete having a specified compressive strength, f 'c, greater than 12,000 psi (82.7 MPa), tie and spiral reinforcement shall comply with the following:
- The free ends of rectangular ties shall terminate with a 135-degree (2.4 rad) standard tie hook.
- The free ends of circular ties shall terminate with a 90-degree (1.6 rad) standard tie hook.
- The free ends of spirals, including at lap splices, shall terminate with a 90-degree (1.6 rad) standard tie hook.
The minimum dimensions of Table 722.2.4 do not apply to a reinforced concrete column that is built into a concrete or masonry wall provided all of the following are met:
- The fire-resistance rating for the wall is equal to or greater than the required rating of the column;
- The main longitudinal reinforcing in the column has cover not less than that required by Section 722.2.4.2; and
- Openings in the wall are protected in accordance with Table 716.5.
See Section 722.5.1.4.
Related Code Sections
722.2.4 Fire and Smoke Protection Features, Concrete Columns
Concrete columns shall comply with this section.
TABLE 722.2.4
MINIMUM DIMENSION OF CONCRETE COLUMNS (inches)
TYPES OF CONCRETE ...
2015 Virginia Construction Code (USBC, Part I) > 7 Fire and Smoke Protection Features > 722 Calculated Fire Resistance > 722.2 Concrete Assemblies > 722.2.4 Concrete Columns
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Concrete columns shall comply with this section. TABLE 722.2.4 MINIMUM DIMENSION OF CONCRETE COLUMNS (inches) TYPES OF CONCRETE FIRE ...
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Cast-in-place concrete protection for steel columns shall be reinforced at the edges of such members with wire ties of not less than 0.18 inch (4.6 ...
2015 Virginia Construction Code (USBC, Part I) > 7 Fire and Smoke Protection Features > 721 Prescriptive Fire-Resistance > 721.1 General > 721.1.3 Reinforcement for Cast-In-Place Concrete Column Protection
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2012 Virginia Construction Code (USBC, Part I) > 7 Fire and Smoke Protection Features > 721 Prescriptive Fire Resistance > 721.1 General > 721.1.3 Reinforcement for Cast-In-Place Concrete Column Protection