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1 <br /> � \\'c rccommcnd tha� a represcntativc from our fimi ohscrre die c�cavation for structural lill. <br /> craluate thc condition of the c�posed suhgrade, mrniiior thc compa,tion of Ihe svuc�ur:�l lill and <br /> Irecommend modifications if rcquircd. <br /> 4.3.2 Footing Design <br /> � 1'1'e recommend continuous wall footinEs hc a minimum of I R incl�es�ridc and isolaicd column <br /> footings he a minimum of?4 inchcs wide. C-�lcrior footings should fx foundcd at Icas1 IR inches <br /> I hclo�r the lowest adjaccnt finished gradc. Interior fornin�s should be fuundcd a minimum ol' <br /> 12 inches belo�e Irnvest adjaccnt soil grade. <br /> Footings undcrlain by at least 3 feet of properlr crnnpacted structural f ill m;ry he dcsigncd for <br /> ' an allm��able bearing capacity of 2,500 psf. Tliis hearing pressure is for �hc comhinaiion of dcad <br /> and long-tcrm live loads, ard may be increased by up to one-third t� account for short-tcnn livc <br /> � loads such as wind or seismic forces. <br /> If footings are construcicd during wet wcather, it may be appropriate to place a Ican concrete <br /> "mud mat" or a layer of crushed rock in footing e�ca��ation bonoms to protect ihc subgrades from <br /> Jdisturbance. <br /> N'c recommend that all footing excavations be observed by a representali��e of our finn <br /> ' immediately prior to mud mat or crushed rock placement, or reinforcing stcel and structural <br /> concrete placement, to confinn that the bcaring surface has been prepared in a manner consisicnt <br /> with our recommendations and Ihat Ihe subsurCacc conditions are as c�peaed. <br /> I4.3.3 Lateral Load Capacity <br /> Lateral loads may be resisted by a wmbination of friction behveen the footing and the <br /> � supporting soil, and by the passive lateral resistance of the soil surrornding the cmbedded ponions <br /> of the footings. A coefficient of friction behveen concrcte and soil of 035 and a passivc lateral <br /> � resistance corresponding to an equivalent iluid densiry of 300 pounds per cubic foot (�c� may be <br /> used for design. The friction coeflicient and passive lateral resistance are allowable values. <br /> If soils adjacent to footings are disturbed during construction, the disturbed soils must be <br /> 1 recompacred,oihenvise Ihe lateral passivc resis�ance value must be reduced. <br /> 4.3.4 Foundation Settlement <br /> � Provided that thc subgrade soils are prepared as described in Sections 4.2 and 43.1 and as <br /> described above, the residual settlement potential of the footings should be on the order of 1 inch, <br /> � total settlement,and % inch diff'erential scttlement mcasured over about 50 feet. <br /> Immediately prior to placing concrete, all debris and soil slough thut accumulated in the <br /> footings during fortning and steel placement must be rcmoved. Debris or Ir�ose soils not removed <br /> � from the footing exca��ations���ill result in increased settlement. <br /> I 4.4 SLAB-ON-GRADE FLOORS <br /> We recommend that the slabs-on-grade be constructed on a gravcl layer to provide unifortn <br /> support, drainage and to act az a capillary break. The gravel layer should consist of 6 inches of <br /> f <br /> � <br /> IG c o L' n g i n c c r s ]$ filcNo. 75gq-pp2.00-I130\050101 I�j- <br />