1001 E MARINE VIEW DR SITE WORK AND UTILITIES 2018-01-01 MF Import

SteNen Jacobson JN 98313 August 17, 1998 Page 5 Parametcr Design Value Active Earth Pressure ' 35 pcf Passive Earth Pressure 350 pcf Coefficient of Friction 0.50 Soil Unit Weight 135 pcf Where:(1)pct is pounds per cubic foot,and(ii)aclive and passive earth prossures are computed using the oqulvalenl Iluid dansillos. • For restrained walls that cannot doflect at least 0.002 times Its height, a unitortn lateral pressuro equal to 25H psi should 6e used as active earth pressure. H is the ettective design height of the wall,Including surcharges. The values given above are to be used to design permanent fuundation and retaining walls only. The passive pressure given is approprate for the depth of level structural fill placed in front of a retaining or foundation wall only. V'Je recommend a safety factor of at least 1.5 for overturning anci sliding. when using the above recommended values to design the walls. The design values given above do not include the effects of any hydrostatic pressures behind the walls and assume that no surcharge slopes or loads, such as vehicles, wiil be placed behind the walls. The surcharge due to tra�c loads behind a wali can typically be accounted for by adding a ur.iform pressure equal to 2 feet multiplied by the above active fluid density. Heavy construction equipment should not be operated behind retaining and foundation walls within a distance equal to the height of a wall, unless the walls are designed for the additional lateral pressures resulting from the equipment. The wall design criteria assumes that the backfill will be well-compacted in lifts no thicker than 12 inches. The compaction of backfill near the walls should be accomplished with hand-operated equipment to prevent the walls from being overloaded by the higher soil forces that occur during compaction. Retaining Wall Backfill Backfill placed behind retaining or foundation walis should be coarse, free-draining, structural fill containing no organics. This backfill should contain no more than 5 percent silt or clay particles and have no gravel greater than 4 inches in diameter. The percentage of particles passing the No. 4 sieve should be behveen 25 and '0 percent. For increased protection, drainage composites should be placed along cut > >pe faces, and the walls should be backfilled with pervious soil. The purpose of these backfill requirements is to ensure that the design criteria for a retaining wall are not exceeded because of a build-up of hydrostatic pressure behind the wall. The top 12 to 18 inches of the backfill shouid consist of a compacted, relatively impermeable soii or topsoil, or the surface should be paved. The ground surface must also slope away from backfilled walls to reduce the po;ential for surface water to percolate into the backfiil. The sub-section entitled Generel Earthwork and Structural Fill contains recommendations regarding the placement and compaction of structural fill behind retaining and foundation walls. �a-o�rrci i�o>�s��i.�r:�xrs_i�c