506 E VIEW RIDGE DR 2018-01-02 MF Import

__;: � � �r... . � 1 " � l �� �� _ � ! t"H V� �� - . � K�� I ro�� i (p H �� I o�g � Jk 91322 � �� Kelvin and Patti Barton page 6 � M g October 22 , 1991 ry5 H� f tn ermanenc I �d� The values given above are t� be used for desic�n of p foundation and retaining walls only. The p�assive pressure �� given is appropriate only for the depth of level structural � f� ll placed in fror`. of a retaining or foundation wall . An appropriate safety factor should 'ue applied when designing the i wa'. ls . We recommend using a factor of safety of at leeist 1 .5 for overturning and sliding. ; � The above design values do not include the effects of any hydrostatic pressures behind the walls and assut�e L'hat no surcharge slopes or loads will be placed above the wa11s • � f these conditions exist, then those p-essures should be added � to the above lateral pressures . Also, if sioping backfill is desired behind the walls , then we will need to be given the � wall dimensions and slope of the hackfill in order to prc �ide the appropriaCe design earth pressures. i Heavy construction equipment should not be operated behind � ;"' � ret��ining and foundation walls within a distance equal to the I I ��,I h�.i�h� of the wall , unless the w:ills are designed for the additional lateral pressures resulting from the equipment. ' ! Placement and compaction of retaining wall backfill should be a�complishe� with hand-operated rquipment. 1 �,�,1 Retaining Mall eackfill � Backfill placed behind retaining or foundation walls I .. should he free-draining structural fill containing no 'I � � � organics. This backfill should conta: n no more than five � (5) percent silt or clay particles �nd have no particles , greater than four (4) inches in diameter . 7he percentage of particles passing the No. 4 sieve should be between 25 'I and 70 perc�ert. Due to thEir high silt content, if the "`+ native sand soils are used as backfill , a drainage composite, such as M� radrain or Enkadrain , should be � placed against the retaining walls . The drainage � composites should be hydra�lically connected to the �� foundation drain system. :he on-site silt soils are not acceptable for retaining wx': 1 backfill . ThF purpose of these backfill requirements is tu ensure �� that the design criteria for th� reteining wall are not exceeded because of a Uuild-up of hydrostatic pressure - behind the wall . The top foot to eighteen inches of th�e backfill ::hould consist of a relatively impermeable soil or to�scil , or the surface should be paved. The sub- �ds�•a�•:r GEOTECH CONSULTANTS , INC.