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.a <br /> ;;-2554 <br /> ratt Land Ass�ciation r,, , � <br /> ru�,ry 27 , L5t45 <br /> i <br /> Ci�r s,lab. F�,otinys Eouni.ed on na' iva silc`-: ur ��n stru�:u�ra] Eiil <br /> m;y be desiyned Er�r an alloW�,ble� �o� l :�car. iny cal�acity �'���t"'all� <br /> f ive liundred ( 250U ) psf . Foot : ,gs tir, riny o❑ �ianse � Y <br /> consolidated till ano hard si1Cs should oe �f�•siyned for a b�:ariny <br /> pr�-tisure of four t:�uusand ( 4UUU ) �s: . �onCinuous and inaividual <br /> s�,rirad footinys should have minimum +�i iChs oE Yweive ( 12) and , <br /> eight.een ( lti) irches� YeSi)<.Ct1V�ly. A one-thircl increase in the <br /> aDove beariny pressures may hc used whe.n consioeriny short t:erm <br /> wind or seismic loads. <br /> For the above design criter. ia, it is anticipated that total <br /> settlements oE Eootinys founded on native �oils and on tills less <br /> tiian cive feet thick Will be on the orcl��r of one-half inch, with <br /> di.`.ferential setClements on the order oE c,nryuarter inch. nlmost <br /> all settlements should nccuc durin�3 constr�ction. If any <br /> cc�ntinuous footinys ar�� located partially in cut :�nd partia �y in <br /> £ill, We recommenil that the sLruct�ral engineer consicier .��iding <br /> a���9itional reinforcement in the footinys and Eooting w�lls near <br /> tne cut-fill transition line to minimize the possibility oE <br /> Eootingsalst ould ebeu extended£eto nnaturalt somis t.in Ithe � lransPti�n <br /> zone. <br /> Lateral loads due to wind or seismic forces may be resisted by I <br /> friction between the foundations a�si ehc ear�Phrtpr ssurzacc�d f�he I <br /> or native subgrade or by Pthe foundations must be poured <br /> t��ndations. For the latter, <br /> "n�at" against the existing soil or backfilled with a compact Eill <br /> ;ueetiny the requirements of structural fill. � coefficient of <br /> iriction of 0 , 35 may be used between th2 structural found�tion <br /> concrete and the supporting subgr.ade. 1'he passive resistance of <br /> ��ndist�rbetl natural soils anA well compacted fill may ue tak.:n as <br /> Nqual to the pressure of a fluid haviny a density oE three hundred <br /> �` ifty ( 35U) pounds per cubic foot (pcf ) . <br /> t�e �ecommend that drains be placed around _all perim�ter Eoot- l <br /> i,�,���_.The drains should be consl-rucl-ed with a four inch dia ter _ <br /> n�rEorated pipe bedded and c��vered with Eree drainin�� ��ra�e L 1'he <br /> ��r�:��s should have a posi=i �e yradient towards suitable discharge <br /> f,3cilities. The footiny d:ninaye system should not be tied into <br /> ;.he roof drainage system u.itil the drains are tightlined well away <br /> � rum the building. The foo�ing excavation should be backfilled <br /> witli granular soil except for the top foot which should be <br /> backfilled with a relatively imp?rmeable soi ? such as silt, clay <br /> or topsoil. �+lternatively, the surface can be se�led with asphalt <br /> or concrete p�v�aments. <br /> Eanh Consultants, Inc <br />