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Section R403.1.1, Minimum Size, of the IRC, is hereby amended by adding the following Table R403.1(4):
For purposes of sizing and construction of footings for residential conventionally light-framed construction with cast-in-place or fully grouted masonry foundation wall construction, constructed upon undisturbed, non-expansive soils, the following table and footnotes may be used in lieu of table R403.1(1), R403.1(2), R403.1(3):
Table R403.1(4)
Number Stories | Foundation Wall Thickness | Minimum Footing Thickness (inches) | Minimum Footing Width (inches) | Minimum Continuous Reinforcement (rebar) | |
Concrete | Masonry
| ||||
1 | 8 | 8 | 8 | 16 | 2 - #4 |
2 | 8 | 8 | 8 | 16 | 2 - #4 |
Demising Walls | 8 | 8 | 8 | 18 | 2 - #4 |
3 | 10 | 10 | 12 | 22 | 3 - #4 |
Demising Walls | 10 | 10 | 12 | 22 | 3- #4 |
a. assumed soil bearing capacity 2000 psf
b. foundations placed upon areas of poor bearing or expansive soils shall be engineered
c. footings carrying point loads shall be engineered
d. foundations may support a roof in addition to the stipulated number of floors
e. foundations supporting a roof only shall be as required for supporting one floor
f. reinforcing shall be evenly spaced with proper overlaps
g. perimeter footings shall be minimum 42” below surrounding grade within 5’ horizontally of foundation
Section R403.1.4.1, Frost Protection, of the IRC, is hereby amended by deleting all existing exceptions and inserting in lieu thereof the following exception:
Section R403.1.4.1 Frost protection exception Detached garages of light frame wood construction of 1,010 square feet or less in size and detached garages of 400 square feet or less in size of other than light frame wood construction and not located entirely within the buildable area of the lot may be provided with a floating slab. The floating slab shall include a thickened slab edge of a minimum twelve (12) inches thick. Six inches of the thickened slab shall be below grade and six inches shall be above finished grade. The bottom portion of the thickened slab area shall be twelve (12) by twelve (12) inches. Two #4 rebar shall be placed within the thickened edge continuous around the perimeter of the slab. Floors shall be of Portland cement concrete not less than 4 inches thick. Garages areas shall have all sod and/or debris removed prior to installation of said floor.
Section R404.1, Concrete and masonry foundation walls, of the IRC, is hereby amended by adding the following paragraph:
Section R404.1 Concrete and masonry foundation walls lateral support Prior to backfill in lieu of a poured in place floor slab to provide bottom lateral support, one of the following may be provided - (1) a full depth (minimum 1-1/2") nominal 2" x 4" keyway may be formed into the footings to secure the bottom of the foundation wall -or- (2) 36" long vertical # 4 rebar may be embedded a minimum of 6" into the footings not to exceed 7' o.c. spacing
Section R404.1.3.2.3, Foundation Walls For Conventional Light Frame Wood Construction, of the IRC, are hereby established by adding the following sections and table:
Section R404.1.3.2.3 Foundation Walls For Conventional Light Frame Wood Construction As an alternate to the requirements of this code the following Table 'Foundation Walls for Conventional Light Frame Construction' may be used:
Table - ‘Foundation Walls for Conventional Light Frame Construction’
Height of Foundation Wall (Net measured from top of basement slab to top of foundation wall)* | Thickness of Foundation Walls | Reinforcement type and placement within Foundation Wall** | Reinforcement type and placement within Foundation Wall** (maximum 12’ span between corners and supporting cross walls) | Type of Mortar | ||
Unit | ||||||
Gross | Net | Concrete | Masonry | Concrete | Masonry | Masonry |
8 | 7’ 8” | 7 ½” | 8” | ½” horizontal bars, placement in the middle, and near the top & bottom – ½” bars @ 6’ max. vertically | 0.075 square inch bar 8’ o.c. vertically in fully grouted cells. If block is 12” nominal thickness, may be unreinforced. | Type M or S. Grout & Mortar shall meet provisions of Chapter 21 IBC |
9 | 8’ 8” | 8” | See Chapter 18 IBC | ½” bars 2’ o.c. horizontally & 20” vertically o.c. (5/8” bars 2’ o.c. horizontally & 30” vertically o.c.) | See Chapter 18 IBC | Same as above |
10 | 9’ 8” | 8” | See Chapter 18 IBC
|
See Chapter 18 IBC | Same as above | |
*Concrete floor slab to be nominal 4”. If such floor slab is not provided prior to backfill, provide 1) 36” vertical #4 rebar embedded in the footing @ maximum 7’ O.C. spacing -and/or- 2) full depth nominal 2”depth x 4”width keyway in footing | ||||||
** All reinforcement bars shall meet ASTM A6184 grade 40 minimum and be deformed. Placement of bars shall be in center of wall and meet the provisions of this Code. | ||||||
NOTE: Cast in place concrete shall have a compressive strength of 3,000 lbs @ 28 days. Footings shall contain continuous reinforcement of 2 - ½" diameter rebar throughout. Placement of reinforcement and concrete shall meet the requirements of this Code. | ||||||
NOTE: Material used for backfilling shall be carefully placed granular soil of average or high permeability and shall be drained with an approved drainage system as prescribed in Section R405.1 of this Code. Where soils containing a high percentage of clay, fine silt or similar materials of low permeability or expansive soils are encountered or where backfill materials are not drained or an unusually high surcharge is to be placed adjacent to the wall, a specially designed wall shall be required | ||||||
Note: Foundation plate or sill anchorage shall be installed in accordance with this code as applicable. | ||||||
Section R405, Foundation Drainage, of the IRC, is hereby amended by adding a new section as follows:
Section R405.3 Sump Pumps Footing drains and drainage systems shall be discharged to a sump pump plumbed to a discharge system separated from the sanitary sewer and in accordance with the standard specifications adopted by the City Council. Exceptions may be granted by the Code Official in accordance with said engineering standards based on local conditions as determined by the Ankeny Public Works Department/Development Engineering Division or Storm Water Coordinator.
Section R507.3, Footings, of the IRC, is hereby amended by deleting existing exception #2 and inserting in lieu thereof the following exception #2:
Section R507.3 exception 2 Decks not supported by a dwelling and not greater than thirty inches (30") above grade plane need not be provided with footings that extend below the frost line.
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