8110 LARIMER RD 2016-01-01 MF Import

GeoTest Services, Inc. 8110 Larimer Road, Evereti, WA Foundation walls, Retaining walls and Lateral earth pressure March 22, 20^,.' Job No.O�•U753 The lateral earth pressures that develop against subsurface building and retaining walis will depend on the method of backfili placement, degree of compaction, slope of backfill, type of backfill material, provisions for drainage, magnitude and location of any adjacent surcharge loads, and the degree to which the wall can yield Iateraliy during or after placement of backfill. If the wall is allowed to rotate or yield so the top of the wall moves an amount equal to or greater than about 0.001 times its height (a yielding wall), the soil pressure exerted will be the active soil pressure. When a subsurface wall is restrained against la!eral movement or tilting (a nonyielding wall), the soil pressure exerted is the at-rest soil pressure. Wall restraint may devalop if a rig�d structural nerivork is constructed prior to backfiliing or the wall is inherently stiff. For non-yielding walls such as foundation walls with level backfill under drained conditions, use the following design dala: Maximum soil density (gravel soil assumed) = 135 Iblft' Coefficient of At-Rest Earlh Pressure Ko = 0.41 At-Rest Earth Pressure equivalent Fluid density = 55 Iblft' For yielding walls such as earth retaining walls with level backfill under dreined conditions use the following design data: Maximum soil density (gravel soil assumed) = 135 Iblft' Coe�cient of Active Earth Pressure Ka = 0.26 Active earth pressure equivalent fluid density = 35 Iblft' Design of subsurface walls should include appropriate lateral pressures caused by surcharge loads located within a horizontal distance equal to or less than the height of the wall. For uniform surcharge pressures, a uniformly distributed lateral pressure equal to 35 percent and 50 percent of ihe vertical surcharge pressure should be added to the lateral soil pressures for yielding and nonyielding walls, respectively. Passive earth pressures developed against the sides of building foundations, in conjunction wilh friction developed beriveen the base of the footings and the supporting subgrade, will resist lateral loads transmitted from the structure to its foundation. For passive resistance of foundation walls against well-compacted fill under drained conditions, use the following design data: Maximum soil density (gravel soil assumed) = 135 Iblft� �oe�cient of Passive Earth Pressure Kp = 3.69 Passive earth pressure equivalent fluid density = 300 Iblft' Coe�cient of Lateral Sliding = 0.35 Page 3 of 5