Laserfiche WebLink
Glenwoocl Tertacc <br /> File Number 126994 <br /> May �2, 1994 <br /> Page 13 <br /> Foundstions <br /> Generel: The foundations for Qie stn�chires should extend tluougl� the fill and be founded on the <br /> underlying medium dense or densc native fill. Convenlional spread footings should be founded directly on <br /> thesc ni+tive soils or on structunl fill or Control Density Fill (CDt) @iat extends to d�cse soils. 'fhe <br /> allemative to conventional foundations is nuger cazt piles. Opcn holcd drilled piers arc considercd not <br /> suitablc for Ihis projcct due to the liigh ground watcr table and thc potential caving condilions. <br /> Eacl� building_f�rinl location sl�ould be evaluated individually to detertnine the most appropriatc <br /> �- _oundatio_�system. It may not be cconamical to remove the fill in many of the footprints to construct a <br /> conventiunal foundation with retaining walls. The explorelion logs should be used to assess the expected <br /> depth of overexcavation for cach slructure. We have provide recommendations Cor bodi tlie conventional <br /> a�iJ decp foundation system in Uiis report. <br /> Conventional Foundalions: '[lie footings should extend a minimum of I foot into lhe mcdium densc or <br /> better na�ive soils. 'il�e botlom of tlic footings sl�ould be scrnped with n smooUi bladcd backhce to nvoid <br /> disturbance of the undcrl}�ng soils. 7he bottom of the footing trenches shoidd be compacted if soils arc <br /> JisturUcd during excavation. 'ILc bcaring soil condilions should be evaluatcd for appropriatc dcnsity and <br /> dep[h nt tl�e time of cnnstn�ction. Extcrior footings sfwuld extcnd a minimum of 18 inches below the <br /> adjacent growid surface with interior colwru� footings extending a minimum of 12 inches below the bottom <br /> of adjacent slab. Minimum fow�dntion widths of 16 and 20 inches should 6e used for continuous and <br /> spread foolings, respeclively. SGwding watcr should not bc;�Ilowcd lo accumalalc in fooling trcnchcs. All <br /> loose or disturbc�d soil sfiould bc removed from ihc foundation ercavation prior to pincing concrete. <br /> For foundations constnictcd �s oullined above ;md foundcd on the medium dense or bettcr nati��c soils, we <br /> recommcnd an allowable design bcaring pressure of 2,000 pounds per square Coot (ps� be used for the <br /> footing design. A one•diird incrcase in lhe above allowable bearing pressure may be used when considering <br /> sl�ort-tcrm trvuitory ��dnd or seismic loads. Highcr foundalion bcnring pressures may be obtained, if <br /> spccific load valucs:md design concepts are provided for our review. <br /> 11ie foundation subgrade soils �vill� high silt wntent will dcgr:ide ���hen exposed to moisture and <br /> construction Ua�c, tf dic foundation soils an; looscned due to moishuc and/or construclion trafiic, we <br /> rcconvnend diat thcy bc protcctcd by a 6 inch blankct of crushed rock or gravel, 71�is matcrial ��ill provide <br /> confincment to tlie underlying soil anJ hclp rcduce the ctTect of thc moisturc. <br /> NELSON-COUVRETTE& ASSOCIATES, INC. <br /> r-Er+-23-iQ4r� iz:r�e zo� nei zsi� 96i r�.is <br />