7818 LARIMER RD B Geotech Report 2022-10-25

For the crawl space to remain free of moisture, it is important that drainage recommendations are properly implemented, and adequate inspections are performed prior to the placement of concrete. • As a minimum, subgrade beneath a structural floor system should be graded so that water does not pond. Perimeter drains, and under -slab drains should be installed in conjunction with a sump pump system to eliminate the potential for ponding and any subsequent damage to foundation and slab elements. The lot -specific perimeter dewatering and underdrain systems should be properly designed and connected to the area underdrain system or a sump -pump system for suitable discharge from the lot. • The underdrain system should consist of adequate lateral drains and a main drain, regular clean out and inspection locations, and proper connections to the sump -pump system for discharge into suitable receptacles located away from the site. • Drainage recommendations illustrated in Figure 8 should be implemented • The entire design and construction team should evaluate, within their respective field of expertise, the current and potential sources of water throughout the life of the structure and provide any design/construction criteria to alleviate the potential for moisture changes. If recommended drain systems are used, the actual design/layout, outlets, locations, and construction means, and methods should be observed by a representative of AGS. RETAINING WALLS Retaining walls should not be constructed without a geotechnical design for the site after site grading plans and project design is completed and made available for our review. In general, for preliminary design, retaining walls for at -rest conditions can be designed to resist an equivalent fluid density of 65 pcf for on -site granular materials. Retaining walls for unrestrained conditions (free lateral movement) can be designed to resist an equivalent fluid density of 50 pcf for on -site granular materials. For passive resistance of unrestrained walls, we recommend passive resistance of 300 psf per foot of wall height. A coefficient of friction value of 0.35 may be used for contact between the prepared soil surface and concrete base. The above recommended values do not include a factor of safety or allowances for surcharge loads such as adjacent foundations, sloping backfill, vehicle traffic, or hydrostatic pressure. We should be contacted to provide additional recommendations for any specific site retaining conditions. Proposed Construction Project No: 0470-WA18 January 24, 2019 Page No: 10 of 17