4708 SEAHURST AVE 2016-01-01 MF Import

' Gcolcchnical Enginecring Gval on 470R Seahurst Avenue--Carter Sep; �nber 17, 2006 RMI File No. 37106 PAgC IO pressure distribulion equrvalem to that exerted by a Ouid wiUi a Aensi�y of 35 pcf for yielding (active condition) wnlls, and GO pcf for non-yiclding (at-rcst condition) walls. I'licsc rccontmended I;�Icra+l c:irlh pr�•tisures arc hased on Ihe assumption of a hori�ontal ground surface adjacent tc lhc wnli for a distanc. of nt Icasl Ihc suhsurfacc hcight of thc ��all. and do not account for surcliargcs. Additional latcnl cartB pressures should hc considcred for surchargc loads actin� ad.jaccnt to thc suhsurfacc walls and ��-i�hin a dislancc cqu��l to lhe subsurfacc hcighl of Aic wall. 'Phis would indudc ihc cf7ccis of surchargcs such as tratTic loads, iloor slab loads, slopes, or othcr surfacc loads. Surchargc effccts should hc considcred il appropriatc. 'Ihc lutcral pressures on walls may bc rcsisicd by friction hetwcen thc fiwndatiun �md subgradc soil, and by passivc rcsistancc acting on thc bclo�c-gradc portion of Uic foundation. Rceonmicnd:rtions liir fric�ional and passivc resislancc to Iateral lo+�ds are prcsented in thc Foundations suhscction of'Ihis rcport. All ��111 backfill should bc �acll compactcd as outlincd in thc Structun+l Fill subscctiun of this rcpon. Cnre should bc taken �o prcvcm thc buildup ot'exccss latcral soil prcssures, due to ovcrcompaction of the wall backfill. This can bc accomplishcd by placing wall hackfill in 8-inch thick loosc lifls and compacting it with small hand-operated compactors wilhin �i di� .:c bchind the wnll equal ro at least one-half the hcight of thc wnll. Pernianent drainage sysicros should be installed for ret.�ining walls and subsurface walls. Wc reconunend tivA Ihcsc drainagc systcros consist of nn I R-inch widc zonc of cican (Icss than 3 perccnt fincs), frcc- draining granular nuucrial piaccd along Ilic back of [he wall. Pco gr.ivel is an acceptable drain material, or dreinagc composite may be useJ itntcad. Wc recommcud that ��c lx� rctained to evaluate Ihe propos-ed wall drain backlill matcrial for its suitability. 'I'hc granular tnatcrinl should bc pinced up thc bnck of thc wall to within l foot of thc ground surfncc. I'hc top I foot should bc a laycr of compactcd, lo�� pcnnenbility soil ro limit surfacc wa�cr infiltration and should he sep:�raled Gom the underlying frce-draining material by a layer of plastic shceting or huilding papcc A rigid pertinaicd or slottcd PVC dninpipa having n minimum diamctcr of 4 inches, should bc embeddcd in pca gra�'c! or somc other frcc-dnining matcrial and wrapped in a non-woven filter f•�bric at thc hase of thc w,ill ��long its entire Icngth. 'I'his drainpipe should discharge into tightlines Icading to an apprupri:ue collection and discharge poinL Surf'ace water drains and roof drains should not hc connccicd �u ��:ill or li,oiine drains until Ihcrc is ai Icast I tiiot cic��ation diffcrencc bclo�� Uie fouting dr.iins. RMI ASSOCIATES LLC � �� �