1318 W MUKILTEO BLVD 2016-01-01 MF Import

Wrought Corporetion August 11, 2006 Coefficient of Fnction 0.45 Passive Earth Pressure 300 pcf Whera: (I) pcf is pounds per cubie foot, and Qi) passiva earth pressure is eomputed using the equivalent fluid density. JN 06287 Page 5 If the ground in front of a foundation is loose or sloping, the passive earth pressure given above will not be appropriate. We recommend maintaining a safety factor of at least 1.5 for the foundation's resistance to lateral loading, when using the above ultimate values. PERMANENT FOUNDATION AND RETA/N/NG WALLS Retaining walls backfilled on only one side should be designed to resist the lateral eaRh pressures imposed by the soil they retain. The following recommended parameters are for walls that restrain Ievel backfill: Where: (q pcf is pounds per cubie toot, and (if) active and passive earth pressures are camputed using the equlvalant fluld pressures. ' For a restrained wall that cannot doHect at least 0.002 times its height, a unifortn loteral pressure equal to 10 psf times the height of the wall should be added to the above active equivalent tluid pressure. The values given above are to be used to design permanent foundation and retaining walls only. It is not appropriate to back-calculate soil strength parameters from the earth pressures and so;l unit weights presented in the table. The passive pressure given is appropriate for the depth of level structural FII placed in front of a retaining or foundation wall only. The values for friction and passive resistance are ultimate values and do not include a safety factor. We recommend a safety factor of at teast 1.5 for overturning and sliding, when using the above values to design the walls. Restrained wall soil parameters should be utilized for a distance of 1.5 times the wall height from corners or bends in the walls. This is intended to reduce the amount of cracking that can occur where a wall is restrained by a corner. The design values given above do not include the effects of any hydrostatic pressures behind the walis and assume that no surcharges, such as those caused by slopes, vehicles, or adjacent foundations wiil be exerted on the walls. If these conditions exist, those pressures should be added GEOTECH CONSULTANTS, INC.