1605 SE EVERETT MALL WAY BOBS BURGER AND BREW Geotech Report 2025-07-25

r JJMD Buildings Bobs Burger&Brew JN 09266 November 18, 2009 Page 6 PARAMETER VALUE • ' Active Earth Pressure* 35 pcf Passive Earth Pressure 350 pcf Coefficient of Friction 0.50 ' Soil Unit Weight 135 pcf Where:(i)pcf is pounds per cubic foot,and(ii)active and passive ' earth pressures are computed using the equivalent fluid pressures. *For a restrained wall that cannot deflect at least 0.002 times its height,a uniform lateral pressure equal to 10 psf times the height • of the wall should be added to the above active equivalent fluid 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 soil unit weights presented in the table. The passive pressure given is appropriate for the depth of level structural fill 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 least 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 ' walls and assume that no surcharges, such as those caused by slopes, vehicles, or adjacent foundations will be exerted on the walls. If these conditions exist, those pressures should be added to the above lateral soil pressures. Where sloping backfill is desired behind the walls, we will need to be given the wall dimensions and the slope of the backfill in order to provide the appropriate design earth pressures. The surcharge due to traffic loads behind a wall can typically be accounted for by adding a uniform pressure equal to 2 feet multiplied by the above active fluid density. Wall Pressures Due to Seismic Forces The surcharge wall loads that could be imposed by the design earthquake, we recommend adding a uniform lateral pressure to the above-recommended active pressure. The recommended surcharge pressure is 7H pounds per square foot (psf), where H is the design retention height of the wall. Using this increased pressure, the safety factor against sliding and overturning can be reduced to 1.2 for the seismic analysis. 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 assume 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 r higher soil forces that occur during compaction. 1 GEOTECH CONSULTANTS,INC.