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Grailieot, load intensity and cros.ion characteristics of slope MBterial . 1805 .4Footings shall be designed an constructed in Allowable bearing capacity of the soil is not exceeded, and That differential settlement is minimized. The minimum Width offootings shall be 12 inches (305 mm) Footings in areas with expansive soils shall be designed In accordance with the provisions of Section 18D5. 8. 1805.4 ./1.1 Design loads, Footings shalJ be designed for the 0l05t unfavorable effects due to the combinations of loads specified in Section 1605.3. The dead load shall in- clued the weight offoundations" footings and overlying fill. Reduced live loads, lIS specitied in Section 1607.9. Are permitted to be used in designing footings. 1805.4.12 Vibratory loads. Where machinery opera- tions or other vibrations are transmitted through the foundation, consideration shall be liven in the footing design to ~cnt detrimental disturbances of the soil. I &05.4 -2 Concrete footings, The design, materials and c0n- struction of concrete footings shall comply with Sections I 8D5.4 2.1 through 18D5.4 .2. 6 and the provisions of Chap- ter lSOS.4-2. Exception: Where a specific design is not provided, coo- Crete footings supporting walls of light-frame construc- tion are permitted to be designed in accordance with Table 18D5.4.2 1805.42.1 Concrete strength. Concrete in footings Shall have 8 specified compressive strength (f'c) ofoot Less than 2,500 pounds per square inch (psi)(17 237 kPa) At 28 days. 1805.422 Reserved. SOILS AND FOUNDAAnONS J 805.42.3 PJain concrete footings. The edge thickness Of plain coocrete footings supporting walls of other than Light-frame construction shall not be less that 8 inches (203 mm) where placed on soil. Exception: For plain concrete footings supporting Group R-3 occupancies. the edge thiclmess is permit- ted to be 6 inches (152 mm),provided that the footing Does not extend beyond a distance greater that the ThickneM of the footing on either side of the supported Wall. 1805.4.2.4 Placement of concrete. Concrete footings ShalJ not be placed through water unJess a !remie or other method approved by the building official is used, Where placed under or in the presence of water" the concrete shall be deposited by approved means to ensure mini- mum segregation of the mix and negligible turbuJence of the water. 1805.4.2.5 Protection of concrete. Concrete footings shall be protected from freezing during depositing and for a period ofoot less than five days thereafter. Water shall Not be allowed to flow through the deposited concrete. 1 &05.4.2.6 Forming of concrete. Concrete footings are permitted to be east against the earth where, in the opin- ion of the building official, soil conditions do not require formin~ Where forming is required, it shall be In accor- dance with Chapter 6 of ACI 318. 1805.4.3 Masonry-WLit footings. The design, materials and construction of masonry-unit footings shall comply with Sections 1805.4.3.1 and 1805.4.3.2. and the provisions Of Chapter 21. Exception: Wh<<e 8 specific design is oot provided, ma- sonry-unit footings supporting walls of light-frame con- Struction are permitted to b designed in IICCOCdance with Table 180S.4.2. 1805.4.3.] DimeIWons, Masoory-wtit footing shall be laid in Type M or S mortar complying with Section TABLE 1805.4.2 FOOTINGS SUPPORTING WALLS OF LIGHT-FRAME CONSTRUCfIONab.c.d WIDTH OF nnCKNESS OF NUMBER OF FLOORS FOOTINGS FOOTING SUPPORTED BY TIlE FOOTINGS'" (inches) (inches) 1 12 6 2 15 6 3 18 8 For 51: I inch = 25.4 mm, 1 foot = 304.8 rom. a. Depth of footings sbalI be in accordance with Section ] 805 2. b. The ground UDder the floor is permitted to be excavated to the elevation of the top oftbe footin8- c. Interior-ctud-bearing walls are permitted to be supported by isolated footings. The footing width and length shall be twice the width shown in this table, and footings shall be spaced not more than 6 Peet on center. d. For thiclcness offoundation walls, see Section 1805.5. e. Footings are permitted to support a roof in addition to the stipula1ed number oftloors, Footings supporting roof only ShalJ be as required for supporting ODe floor. ( Plain cooaete footings for Group R-3 occupancies are permitted to be 6 inches thiclc.