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Jul 14 06 03:08p GBT Construction INC <br />3UL-14-2006 FRI Oi�53 ?tl HWA GEOSCIENCES <br />)uly 14, 2006 <br />I1WA Projcct No. 2006-000-21-iU54 <br />4255140652 <br />FAX N0. 42577427i4 <br />pilcs consist of drillul, cast-in-placc conc�ct� cylinda pier clancnls. Pile diametcrs of <br />12 to 16 inchcs arc concidcred sufficicnt for support oCthv strudure and should be <br />dcsi�ncd sulely on thc basis of skln•friction betwecn pilc shaft and in situ soil. 1Vc <br />n:commend an allowab:a design skin-friction value of 1000 psf be uoplaycd for this site. <br />IIowcvcr, the upPcr 5-fcct oCpilc shaA should be considacd to contrihute no lond <br />support dur to potential loss of ground associated with a shalfow skin slide enctoaching <br />on t3ie pile systcm. Baseil on thc allowablc bcari��g vatue of 2000 psf that has becn used <br />for dcsign nf �e footings for this st�ucture, we anticipatc that tutal pite tengihs of 12 and <br />]A fect w.uld bc reyuind for l6 and 12-inch diameter piles, respcctivcly, spaced on <br />?U•t2iut centcrs. llowcvcr, your stnuturd eugincer should design the piles basecl on pile <br />size, snacing and ]oads he considecs appropnate for the specific structural conditions. <br />We re.commaid that the piers bo constrvcted with full-deplh reinforcing in uncascd drill <br />hotcs. Altl�ough pile,a are not considcred necessary For foundation sup}�ort inboa� of tlu <br />nortli perimeter �aall, we recornmend that the footings end/or foundation walls bc <br />pro��idecl with additional reinfoccang steel in the first 10-foot inter:;,l betwern <br />pilc-suppnrted :.nJ non-pilcd foundaHon. This will allou� thc footingsltoundation walls to <br />span wiy arca that may becnme uudcimincd inboard of the pilc-supportcd wa!1. <br />All'hnugh nuga-cast piles might be utilizcd, we believe thut Ch� densc till will caus� <br />substantixl di{iicultics tn advancement of the augcr and attainmeni ofthe penetration <br />deptha required. ncmrdingly, we do not advocate auger-cazt pilu foz this site. Driven <br />pilc sys�emc are also not considcrod suitabic for this sitc. <br />COnD171oNs nNo LrMIrnTluxs <br />Wc havc conducted this geoteclinical cngincering ass�sment in support ofyour <br />constn�dion of the proposed re,iJential st�ucNre on sitc at the iocution currently laid out. <br />7'his rcpuri and any uthcr applicablc gcotcchnical data should bc vicwcai in ilc entirety; <br />conclusions aud intcmtGations shoulJ not, howcva, bc construcd us our weTranty oEthe <br />subsurfacc conditions. F,xpericitice has shown that subsw{ace soil and ground water <br />conditions can vary significnn[ly ovcY small ciistances and ovcr timr, hence, wc may not <br />I�ave sccn cvcry condition anJ even those wc obscrved could changc with tin:c. <br />"['he scoPo ofwork did not include a physical subsurfaca investiUatio�, nor wcre <br />enviro:vnrntal a�sessmenla, ond evaluntions regarding the presenec or absence af <br />wctlands or hva�dous substanccs in the soil, surfacc wata, or gound water perfortncd at <br />thia sitc. ILWA docs not practice or consvlt in thc field of safety rngineering. Wc do nnt <br />dired t1�c cantraclor's oper�tions and wc cunnot bc nK�onsible for thc safcty of pe�anncl <br />u�her .'�an our own on thc sitc; �hc safety ofothers is thc responsibility of U�e contractor. <br />The contrrctor sltould, howe�•er, notify the owncr if any oClho recommended actions <br />prescntcd hcrcin aro considcrcd unsafc. <br />4712 5rw 6nr. e W:y <br />p.2 <br />r. u5 <br />HWA GL'OSciences ixc. <br />�� <br />