10105 19TH AVE SE Geotech Report 2018-01-02 MF Import (2)

�� - � KA No. 092-06160 October 25, 200b Page 7 Drainagc and Landscapine The ground surface should slope aw�y Gom building pads and pavement areas, toward appropriate drop inlets or othcr surface drainage devices. It is recommended that adjaccnt exterior grades be slopcd a minim»m of 2 percent for a minimum distance of 5 feet away from structures. Roof drains should be tightlined away from foundations. Subgrade soils in pavcment areas should be sloped a minimum of 1 percent and drainage gradients maintaine.� to carry sll surfacc water to collection iacilities and off-site. These gradcs should bc maintained for thc life of the project. Spccific rccommendations for and design of storm water disposal systems are beyond the scope of our services and should be prepared by othcr consultants that are familiar with design and dischargc rcquirements. Infiltration syslems should not bc located on slopes that excecd 30 percent, nor should systems be "st�cked" or lincd up with one anothcr down the slo�e. In6ltration systems should not be locaied ap slope of residences or rctaining stntctures. Utility Trench Backtill A contractor experienced in such work should excavate utility trcnches in acc�rdance with Occupational Safety and He�lth Administration (OSHA) standards. The responsibilily for the safeiy of opcn trcnches should be bornc by the contractor. Traffic and vibration adjacent to trench walls should be minimized; cyclic wetting and drying of'excavation side slopcs should be avoidcd. Depending upon tt�e location and depth oFsome utility trenches, groundwater floc� into open excavations could be experienced, especially during or shorily following periods of precipitation. Although dense glacial soils, which gene�ally have cohcsive strength, were encountered at relatively shallow depths below the existing sitc grades,beddin�and joint(fracture)planes in thcsc soils may still causc caving in trench wall cxcavations. Shoring or sloping back trench sidcwalls may be required within these soils. All utility trcnch backfill should consist of imported stnictural fill or suituble on-site material. Utility trench backfill placed in or adjacent to buildings and exterior slabs should be compacted to at least 95 percent of thc maximum dry density based on ASTM Test Mcthod D1557. The upper 5 fcct of utility vench backfill placed in pavement arcas should be compactcd to at;east 95 percent of thc maximum dry density bascd on ASTM Test Method D1557. Delow 5 fcet, utility trench backfill in pavement azeas should bc compacted to at least 90 perccnt of t.�e maximum dry density based on ASTM I'cst Method D 1557. Pipc bcdding should be in accordance with thc pipc manufacturer's recommendations. The contractar is responsible for removing all watcr-sensitive soils from ihc trenches regardless of the backfill location and compaclion requirements. Thc contractor should use appropriate equipment and mcthods to avoid dumage to the utilities and/or structures during fill placement nnd compaction. Krazan&Assacletee,Inc. � Offices Serving The Westem Uniied States ��\ 1