4818 BELVEDERE AVE 2016-01-01 MF Import

Novcmber 9, 2006 Single-Pumily Residence - Bclvederc l,ot 4 L&A J�h No. GA149 Pagc 11 at the top should be designed for active Ixteral soil pressum. We rccommend lhat u lateral soil pressurc of 50 pcf EPD (equivalent tluid density) be used for the design of fountintion walls restruined nt the top; snd 35 pcf EPD for retnining wnlls unnstrained at lhe top. I o counter the active soil or at-rest press��e, a passi��e laterui soil pressure of 350 pcf GFD may be use�1, except that the passive pressure within thc top 12 inches of the finish subgrade should be ignorcd. The above laternl soil pmssures are under the assumption that groundwater behind the walls is fully drained. 7'o resist against sliding, the friction force between the fo�tings and the subgrade soils may be calrulated based on a coefficient of friction of 0.60. The above soil parumeters are ultimatc valucs, and proper factors of eafety should bc used in the design of lhe basement nnd rctaining walls against sliding and overtwning failures. Basement walls or retaining wulls may be suppo�tcd on footing foundations seated on or into the underlying, dense to very-dense Esperance Sund deposit, with un allowable soil bearing pressure not w exceed 3,000 psf. A vcrtical drainage blanket consisting of ut Ieast 12-inch-thick free-drnining pea gravel or washed grnvel should be placed on thc upslope side of fiwndation and retaining walls to prevent eccumula;' in of groundwater bchind and buildup of hydrostatic prcssure against the walls. The drainuge blanket should bc of a cican, Gec-draining, granular material, conteining no more than 3% by wcight of fines passing the No. 200 sieve, based on thc fraction passing lhe No. 4 sieve. This free-draining backfill should be compacted to the minimum dry densiry recommended in S7'RUCTURAL F1LL section of this rcport. Thc top 12 inches of backfill should consist of compactcd, on-site soils. The backfill materinl for the foundation �nd rctaining walls should be compacted with a hand-opemted compactor. Heavy compuction equipment should not be allowed closer to the walls than a horizontal distance equnl to the wall heights. A footing drnin, as recommendcd in the DRAINAGG CONTftOL section of this rcport, should also be provided for G�undation and retaining ��alls. LIU & ASSOCIATES, INC.