5720 EAST DR 2018-01-02 MF Import

Geotechnical Engineering Report Parcel 00471700002401- 57XX East Drive Everett, Washington December 12, 2009 RMI File No.53409 Page 4 Any disturbed areas should be restabilized as soon as possible through vegetation planting or other approved means. Within exposed soil areas, vegetation planting, hydro -seeding, and/or straw mulching are effective means to minimize erosion and allow vegetation to begin rapidly. All excavation spoils should be covered with plastic in the event of rain to minimize the potential for erosion and siltation. Seismic Considerations The Site Class is shown as C in Table 1613.5.2 of the 2006 International Building Code (IBC). Hazards associated with seismic activity include liquefaction potential, slope instability, and amplification of ground motion due to soft soil. The medium dense to very dense soils that are interpreted to underlie this site do not have a significant potential for liquefaction or amplification of ground motion but surficial slides of loose soils at the surface of the slope may occur. The hazard associated with seismicity for sites underlain by sands is primarily liquefaction. The type of soil that is most susceptible to liquefaction during an earthquake is a saturated loose fine to medium - grained sand deposit. A loose saturated sand deposit when subjected to vibration tends to compact and decrease in volume. If the sand deposit does not drain the pore water pressure increases. If the pore water pressure is allowed to build up by continuous vibration, a "quick" condition will be reached when the pore pressure equals the effective overburden pressure at some depths. Under this condition the sand is temporarily transformed into a liquid state and loses its load bearing capacity. As these soils are well drained and medium dense to very dense we consider the liquefaction potential for this site to be low. Site Drainage Surface Drainage: It is desirable that positive surface drainage be provided so as to direct surface water away from the foundations of the building. Ponding of surface water should not be allowed adjacent to the structure nor in any area where footings, slabs or pavements are to be constructed. It is recommended that the ground surface next to the building be sloped at about 3 degrees away from the building for a minimum of 10 feet. It is imperative that concentrated water flow not be allowed DS116' f RMIASSOCIATES LLC