4812 HARBOR LN 2018-01-02 MF Import

December3, I"S Project No. T-41" Exrevedoes Site excavations of more than four feet should be laid back at a minimum slope inclination of 1:1 (Horimntal:Vertical). If there is insufficient room to complete the excavations in this manner or if excavations greater than 20 feet in depth are planted, the use of temporary shoring to support the excavations may need to be considered. If it appears that shoring is required, we should be contacted to provide necessary parameters for design and construction. The abovc information is provided solely for the benefit of the owner and other design consultants, and should not be construed to imply that Terra Associates, Inc. assumes responsibility for job site safety. It is understood that job site safety is the sole responsibility of the project contractor. 4.4 Foundations Spread Footings The building may be supported on conventional spread foundations bearing on competent native soils or on structural fills placed above competent native soils, as recommended in the Site Preparation and trading section of this report. Competent native soils are considered as dense silty sand/sandy silt encountered at depths of five feet and three feet at Test Borings B-1 and B-2, respectively. Perimeter foundations should be placed at least 1.5 feet below final exterior grades for frost protection. We recommend designing foundations for a net allowable bearing capacity of 2,500 pounds per square foot (psf). For short -tern loads, such as wind and seismic, a one-third increase in this allowable capacity an be used. For the anticipated building loads and this bearing stress applied, building settlements should be negligible. For designing foundations to resist lateral loads, a base friction coefficient of 0.4 can be used. Passive earth pressures acting on the side of the footing and buried portion of the foundation stem wall can also be considered. We recommend calculating this lateral resistance using an equivalent fluid weight of 300 pounds per cubic foot (pcl). We recommend not including the upper 12 inches of soil in this computation as it can be affected by weather or disturbed by future grading activity. This value assumes the foundation will be constructed neat against competent native soil or backfilled with structural fill, as described in the Site Preparation and Grading section of this report. The passive value recommended includes a safety factor of 1.5. 4.5 Lateral Earth Pressures The magnitude of earth pressure development on lower -level or retaining walls will partly depend on the quality of the wall backfill. We recommend placing and compacting wall backfill as structural fill, as recommended in the Site Preparation and Grading section of this report. To guard against deveiopment of hydrostatic pressure, wall drainage must be installed. A typical wall drainage detail is attached as Figure 4. Page No. 6