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Gnuii e.ol, 10JId intensity an d eros..i an chanlcte.risti cs of EJ ope Material. 1805.4Footings shall be designed an constructed in Allowable bearing C8pacity of the soil is not exceeded, and T1ud d i fferentiaJ settlement ill minimized. The minimum Width of footings shaJI be 12 inches (305 nun) Footings in areas with expansive soils shalJ be designed In liCCOrdance with the provisiom of Sectioo 1805.8. ] 805.4./] ,1 Design loads, Footings shallge designed for the ID05t unfavonr.blc effecu due to the combinations of loads specified in Section 1605.3. The dead load shal.I in- clued the weight offoundations" footings and overlying fill. Reduced Uve loads, 13 specl1ied in Secdoo 1607.9. Are permitted to be used in designini footings. 1805.4. 1 2 Vibllltory loads. Where machinery opera- tions or other vibrations arc b"an3mitted through the foundation, consideration shall be &ivell in the footing design to prevent dcui.mcntal disturbances of the soil. I &05.42 Concrete footing&, The design, matcriala and c0n- struction of coocrete footinp shaH comply with Sections 1805.4.2.1 through 1&05.4.2.6 and the provisions o(Olap- ter I 8()j.4.2. Exception; Where a specific design is no( provided, c0n- Crete footings supporting wal.ls of light-frame coostnJc- lion are perm.ined to be dC3igned in accordance with Table J &05.4.2 1&05.4.2. J Coocretc strength, Coocrete in f~ ShaI1 have 8 spcoificd COOlpnlSaive R:rengtb (re) ofoot Less than 2,500 pounds per square inch (PSi)(J 7237 kP8) At 28 days. 1805.422 Reserved. SOILS AND FOUNDAA 110NS 1805.4.2.3 P1ain 00lICrete footings. T1u ~ thickness Of plain c:oocme footinp supporting walls of other than Light-frame construction s.haU not be 1es.5 that 8 inches (203 nun) where placed on soil. Exception: For plain concrete footings supporting Group R-3 OCCUpancics. /he edi~ thickness is permit- ted to be 6 inches (J 52 mm),provided that the footing Does not extend bcyood a diSl.3nce greater that the ThicJcnes., of the footin~ ~ either side of the supported Wall. 1805.4.2.4 Placement (If coocn:te. Cooaete footlng5 Shall not be placed through WBV'.r unless 8 trcmie or other method approved by the building )fficiaJ is used., Where placed under or in the preIlenCe of water" the concrete shall be deposited by approved meam to ensure miru- mum segregation of the mix and negligible turbulence of the water. 1805.4 ,2.5 Protection of concrete. Cona-cte footings shall be Protected from freezing cIurins depositing and fOi II period of not less than five days thereafter. W 8ter shall Not be alJowed to flow through the deposited concrete. 1 WS .4.2.6 Forming of concrete. Concrete footings are permitted to be cast againJt the earth wber-e, in the opin- ion of the buiJdin& official, soil condit:ion.s do DOt require forming. Where forming Is required, It sha1I be In acror- dance with Olapter 6 of ACl318. 1805.4.3 Masonry-unit footings. The design, materials and construction of masonry-unit footiDg3 sbaJI comply with Secti<m 1805.4.3.1 and 1805.4.3.2. and the provisions Of Chapter 21. Exceptioo: ~ 8 specific design is DOt provided, lIl&- soruy-unit footings supporting walls of light-frame con- Struction are pcnnitted to b designed in accordance with Table IBOS.4.2. 1805.4.3.1 DimaWoos, Masoory-unit footing abalJ be laid in Type M or S mortar complying with Section TABLE 1805.4.2 FOOTINGS SUPPORTING WAllS OF LIGHT-FRAME CONSTRUcnONa.b.c.d WIDTH OF nnCKNESS OF I NUMBER OF FLOORS FOOTINGS FOOTING SUPPORTED BY THE FOOTINGS. (inches) (inches) I 12 6 2 15 6 3 18 8 For S I: I inch = 25.4 0lDl, 1 foot... 304.8 mm. a. Depth offootings sbalJ be in accordaoce with Sectioo 18052. b. The ground under the floor is permitted to be excavated to the elevation of the top of the footing. c. lnb::rior-t:tud-bearins wa11a are pamiUed to be IUpported by isolated footings. The footing width and length GhaJI be twice the width shown in this table, and footings shall be spaced not more than 6 Feet on center. d. For thickness offoundatioo walls, see Section J805,5. c. Footings are permjUed to 5UppOft . roof in addition to the stipulated nwnber of floon, Footings supporting roof OI1)y Shall be as rtquired for supporting one floor. ( Plain COOCftte footings for Group R-3 occupancies are permitted to be 6 inches thid.