2109 MCDOUGALL AVE 2018-01-02 MF Import

Geotechnical Engineering Eva."dtion 2109 McDougall Ave, Everett -Cobb February 14, 2007 RMI File No.34206 Page 3 lightlines leading to an appropriate collection and discharge point. Roof drains should be lightlined separately of footing drains. All drainage should be routed to an appropriate discharge point. Foundations Conventional shallcw spread foundations should extend through any fill and should be placed on undisturbed medium dense or better native soils. Footings, including interior footings, should extend at least 18 inches below the lowest adjacent finished ground surface for frost protection and/or bearing capacity and lateral resistance considerations. Minimum foundation widths of 18 and 24 inches should be considered for continuous and isolated spread footings, respectively. Standing water should not be allowed to accumulate in footing trenches. All loose or disturbed soil should be removed from the foundation excavation prior to pouring of the concrete. For foundations constructed as outlined above, we recommend an allowable design bearing pressure of not more than 3,000 pounds per square fool (psi) be used for the footing design if footings are foundr ' on the very dense unweathered till. if footings are placed on the weathered till the bearing pressure should be restricted to 2000 psi. Current International Residential Code (IRC) guidelines should be used •vhcn considering increased allowable bearing pressure for short-term transitory wind or seismic toads. Potential foundation settlement using the recommended allowable bearing pressure is estimated to be less than 1 inch total and 1/2-inch differential between adjacent footings or across a distance of about 25 feet. Lateral loads may be resisted by friction on the base of the footing and passive resistance against the subsurface portions of the foundation. A coefficient of Iriction of 0.35 may be used to calculate the base friction, and should be applied to the vertical dead load only. Passive resistance may be calculated as a triangular equivalent fluid pressure distribution. An equivalent fluid density of 200 pounds per cubic foot (pef) should be used for passive resistance design. These recommended values incorporate safety factors of 1.5 and 2.0 applied to the estimated ultimate values for frictional and passive resistance, respectively. To achieve this value of passive resistance, the foundations should be placed "neat" (without fortis) against the native medium dense or better soils or compacted soil should be placed against the faces of the footing. We recommend that the upper foot of soil be neglected when calculating the passive resistance. The soil surface should be horizontal in front of the footing for a distance equal to at least three limes the depth of embedment of the footing. RMI ASSOCIATES LLC (�'