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

1 JJMD Buildings Bobs Burger&Brew JN 09266 ' November 18, 2009 Page 5 ' SEISMIC CONSIDERATIONS In accordance with Table 1613.5.2 of the 2006 International Building Code (IBC), the site class ' within 100 feet of the ground surface is best represented by Site Class C (Very Dense Soil and Soft Rock). The site soils are not susceptible to seismic liquefaction because of their dense nature. As noted in the USGS website, the mapped spectral acceleration value for 0.2 second (Se)and 1.0 sec (S)equals 1.21g and 0.43g, respectively. CONVENTIONAL FOUNDATIONS We recommend that continuous and individual spread footings have minimum widths of 12 and 16 inches, respectively. Exterior footings should also be bottomed at least 18 inches below the lowest adjacent finish ground surface for protection against frost and erosion. The local building codes ' should be reviewed to determine if different footing widths or embedment depths are required. Footing subgrades must be cleaned of loose or disturbed soil prior to pouring concrete. Depending upon site and equipment constraints, this may require removing the disturbed soil by hand. An allowable bearing pressure of 3,000 pounds per square foot (psf) is appropriate for footings supported on competent native soil. A one-third increase in this design bearing pressure may be used when considering short-term wind or seismic loads. For the above design criteria, it is anticipated that the total post-construction settlement of footings founded on competent native soil will be less than one inch, with differential settlements on the order of one-quarter inch in a distance of 25 feet along a continuous footing with a uniform load. ' Lateral loads due to wind or seismic forces may be resisted by friction between the foundation and the bearing soil, or by passive earth pressure acting on the vertical, embedded portions of the ' foundation. For the latter condition, the foundation must be either poured directly against relatively level, undisturbed soil or be surrounded by level structural fill. We recommend using the following ultimate values for the foundation's resistance to lateral loading: ' PARAMETER ULTIMATE • VALUE Coefficient.of Friction_ __ _- _ 0.50-_- ' Passive Earth Pressure 350 pcf ' • Where:(I)pcf is pounds per cubic foot,and(ii)passive earth pressure is computed using the equivalent fluid density. ' 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 RETAINING WALLS Retaining walls backfilled on only one side should be designed to resist the lateral earth pressures imposed by the soil they retain. The following recommended parameters are for walls that restrain level backfill: 1 GEOTECH CONSULTANTS,INC.