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Augusl 18. 20U•! <br />Mr. Jim 'I hnm�is <br />13clvcdrrc Lols 12 and 33 <br />I.KA .luh Nu. 4nURR <br />Pagc I S <br />BASI?MI?N'1' AND RI;1'AININC 11'AI.I,S <br />13ascmcnl walls rrstrainrd horizonlally al thc top are cunsidcrcd un��iclJing and shuulJ hc <br />dcsigncd fur a lalcrnl soil pressurc undcr thc at-rcs1 cunJilion: �chilc rclaininµ walls Gcc to moec <br />at Ihc top should hc dcsigncd liir aclivc ialrr�il soil pressurc. Wc rcconnncnd Ih:U a lalcral soil <br />pressurc of 55 pcl' IiPD bc uscd lur thr dcsign of finmdatiun ���alls restraincJ al lhc �up; an� 40 <br />pcl' lil�l) lin• ret.iining walls unresiraincd :d thc lop. 'fu cauntcr ihc activc soil or ;d-rest pressurc. <br />a passi��c latcral suil prcssurc ul' 350 pcf IiPD nwy bc uscd. cxccpl Ihal thc paxsivc pressurc <br />within lhc tup I? inchcs of thc linish subgradc should bc ignored. 'llt, ahovc lalcral soil <br />prrssures am undcr thc assumption Ihnl grounJ���alcr bchiod thc walls is fully draincJ. 'fo rcsisl <br />againsl sliding. Ihc I�riction ;iircc bch�ccn Ilic �i�otings and Ihc suhgr,idc soils may bc calcul:dcd <br />based on a cocl7icicnt ol' I�riclion of O.GO. 7'hc aho��c soil paramrlcn are ullimalc valucs. and <br />proper laclots uf salcly shuuld hc uscd in thc dcsign uf Ihc bascincnl nnJ rclainiug �calls againsl <br />sliding anJ uccrturning failurrs. I�ascmcnl walls or rct:iinin� walls may bc surporlcd on li�oling <br />li�undalions scatcd on or intu �hc undcrlying, tcry-slil'I' 1�� h;vJ siL' or thc dcnsr �u eci}�-dcnsc <br />Isperancc Sand �Ic�msits. �eilh �m allowablc soil hcaring pressurc nul lu cscccJ 2.5011 psl'. <br />n crr�ir.il ch,iin,igc blankcl cunsis�ing uf:d Icast 12-inch-ihick I'rcodraining pca gravrl or �rishcJ <br />gr.i�cl shuul�l hc ��lacrd on thr upslopc sidc of IiiunJ�ilion anJ rctaining �valls to prcvrnl <br />accumulnliun ul gruund��alrn c�hind nnd huildup uf h�druslatic pressurc ugainsl Ihc nalls. 'I�lic <br />Jrainagc hlankrl shnulJ hc of a cican. 1'rcc-draining. gr,mul:u� matcriul, conlaining no morc Ihan <br />3'%� h� ��cighl ol lincs passiug Ihc No. 200 sic�c, h�iscd un Ihc I�r,iction passing �hc Nu. d sicvc. <br />Ihis Ihc-dr.iining hacklill shuulJ hc compaclrJ lu tlir mininmm dry dcnsity rccummcnJcJ in <br />S'I KU("Illltnl. I II_I. sccliun uf Ihis rcporl. 'fhc lop 12 inchcs of backlill shoulJ consist �if <br />cnmpacicJ. un-silc suils. 'I hc hacklill nuitcrial lirr tlic �hundaliun anJ rctaining walls should bc <br />cum��acic�l ��ilh a h�utd-���irra�rJ cnm��xlor. Ilca�}' contr:icliun cqui(mtrnt should nol hc <br />;ill����r�l cl��.cr in ihr ��:ill, than ,i h��riiuni,il �lislanrr ryual lu thr •,c:ill hri�hts. �1 fnntin� drain. <br />LIU S� ASSUCIATI�,S, INC. <br />I �}/ �\ <br />/L <br />