Laserfiche WebLink
nnr�i �, zoos <br /> Mr. Don Levin <br /> L&A Job No. 8A037 <br /> Pagc 12 <br /> bc used for latcral resistancc. Thc abovc passivc pressure assumcs that thc backfill is Icvcl or <br /> inclincs upward bchind thc foundations for a horirontal distmicc at Icast hvicc thc depth of ihc <br /> foundations bclo�a final gradc. A cocfficicnt of friction of O.GO bct�vccn thc foundations and ihc <br /> subgradc soils may hc uscd. Thc abovc soil paramctcrs arc imf:�ctorcd valucs, and a proper factor <br /> of safcty shotdd Uc used in calculating the resisling forces against lateral loads on the buildings. <br /> [3ASF.�IEN'I' �VAI.LS <br /> I3ascmcnl walls of thc proposed ncw residcncc ���ould bc restraincd at thc top from latcral <br /> movement anJ should bc dcsigncd for a latcral soil pressuro undcr the at-rest condition. �Vc <br /> rccommcnd that an at-rest soil pressurc of 45 pcf Ef D (cquivalcnt (luid dcnsity) bc uscd for lhc <br /> dcsign of hascmcnt walls or eslcndcd footing walls. To countcr thc abovc acti��c soil pressurc, a <br /> passivc latcral soil pressurc of 350 pcf BPD may Uc used. To resist against sliding, thc Giction <br /> forcc bchvccn thc footings and thc subgradc soils may bc calculatcd based on a cocfficicnt of <br /> friction of O.GO. Thc abovc soil paramcicrs arc ultimatc ��alucs bascd on a fully draincd condilion <br /> of thc walls, and proper f:ictors of safety f:�clors should bc applicJ in thc dcsi�n of thc Uascmcnt <br /> ���alls or cztcndcd li�oting��'alls against sliding and ovcrturning lailures. <br /> A �crtical draina��c blankct. at Iccist I?-inch-thick horizontally, consisting ofcican, frcc-draining, <br /> pca gravd or �vashed gra��cl or crushcd rock, should bc placcd against thc back of bascmcnt or <br /> cxtcndcJ footing �valls to prcvcnt accumulation of growidwatcr 6chind and buildup of <br /> hydrostatic pressurc against thc �valls. This drainugc blankct fill should bc compactcd to a non- <br /> yiclding statc wiQi a ��ibratory cotnpactoc Structural fill should bc uscd for Uackfilling thc wa!Is <br /> bchind thc vcrtical drainagc blankct. "I'hc top 12 to 1S inches of thc backfill may consisl of <br /> compactcd, dr.m, on-sitc granular soils. In ordcr not to daivagc thc bascment walls, only hand- <br /> hclJ. light-���cight, compaction cyuipmcnt shuuld bc allowcd �rithin a horizontal distancc of thc <br /> ,� <br /> LIU & ASSOCIATES, INC. ' '� ) <br /> � � ! 1 ;i <br />