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�Ir. .lames Gallo�vav <br />� Septeii�ber 6, 20l 1 <br />Stritcturai Fiil <br />C�Ut' SfUCIy' IIIC�IC�II;S 1i18t lI]i; native soiis cantain a sut�ficienl p�rce��ta�e of ti»cs (silt and clay size pariicles} that <br />�vill make them difticult to compact as structural iill if they arc too �vet or t�o dry. Accordinely, the ability to use <br />native soils from site exca��ations as structural fill �vill de}}end on i►leir maisture content and thc ��revailin� <br />�ti�eatiler conditions �vElen site-grading activitics take place. Native sc�ils that are too ���et ta properly c�in��act <br />could be dried b�� �eratiail dtirin� dry �veathei� c<�nditio�ls or �nixed n�ith an additi��e such as ccment, c�:ment kilii <br />dust (CKD) or limc to st�ibilize the soil �nd facililat� c��mpaction. If an additivc is us�d, additional Best <br />Mana`�ement Practices {BMPs} for its use �� ill need to bc in�oi-�orated inta the 'i�empc>rary l:rosi«n ancl <br />Sedimentation Coilh�ol E�lan ("i'ESC) for tlic projcct. <br />It' gradin� acti��ities are planned during the weI ���inter months. or if th�y are initiated durin� th� summer and <br />extend into fa]I and «�inter, tfl� t���'11Cr S�1C1L1I(J l�C })Il;�l'r11'C(j �O II11�7()fI �;-c;t �veather structur�l iill. For this p�irpose, <br />�{�e r�commend imporiinc a�,rantilar soil tilat mee(s tlie follc��vitig gr'aciing req��irements: <br />L;,S. Sie� e Sirc Percent Passin� <br />F inches 100 <br />__ No. 4 "� »ia�in�um <br />Na _'• DO � ntaximum'� <br />'�Based ocl the 3!�-inell fi•actic,�l. <br />Priar to use, Terra r�ssociates, l�lc. sh�uld examine a�lcl test atl materials icnported to the site for use as structtiral <br />tlll. <br />Sti�uciur�f tiil shoul�f be placed in unitorm lo<�se layc;rs not cxcee�line 1? inches and compacted to a�nitliinum �if <br />95 percent �f t��e s�il�� ma�imum dr� density, as deterntined by Ameri�an Societv for Testin� and Matcrial; <br />(ASTM) Test Designation D-69� (Sls�udard Pmetor}, The m�isturc content of the soil at the time of� com��action <br />sliould bc u�itliin tivo E�erc�nt ot� its optiillum, a� cl�t�.i-n�iii�d by thi� AST'M staildard. In nonstru�tural ac�eas ar l�or <br />hacklill in utility tren�l�es bcic��r a cfe3�t11 of4 t�ct, tltc de��ree c�f compactio[i c�ti l�e reciticecl tu 9U j�cra�»t. <br />roundltions <br />Ti�e addition may be suppnrtcd on conv�nti<mal sprcad foundations bearing on competent native soils or on <br />structw�al till placed al�ove competent native 5�ils. Poundatic}n subgrade and stiuctural till sliould be prcpared as <br />reeommended in the Site Preparation and Stn�ctural riil sections of t}Iis report. Perimeter foundations exposed to <br />the �rcather should be a minimum dc��th of' 1� ii�cl�es helow final exterior t�rades. Interior t�ounda�ions can be <br />consttucted at any coFlvenient depth helo�v the stnictural tloor slab. f�s nc�ted earlier, tor stability considerations, <br />f'ootings paralleling tlle slope c�•est �vill �leed to be deepericd to provide a miiiiml�m setback distazlce of ten feet as <br />measured ti-om ihe �d�e of tfie toundation iooling t�� the slope face. <br />Fourldations bearing on competent native soil or structural iill can he diil�eiisioned for a tlel aIlo�vable E�cari�l,* <br />capacity of 3,000 pounds per square t��c�t (psl�. ��or sl��i7-term loads, sucll as �vind and seismic, a �ne-tl�ii•d <br />increase i�i t}�is allo�vable capacity can be used. Witll stru��lura] loadin�� as ailficipateci and this bearin�� stress <br />applied, total foundation settlemznts aii estimated to less than one-i�alf� inch, res3�ectivel��. Buildin� settlemet�t <br />SI1011IC{ OCCUC ICl RI7 It11111CC11aI� 11�1I111"e a� 1)UIIdIII� I<�ads are ap��Iied. <br />I'roject No. T-5�#71-Z <br />I'a�;e No. � <br />