12906 19TH AVE SE FRED MEYER FUELING STATION 2018-01-02 MF Import

Geotechnical Engineering Report d Jnne 27, 2008 Fred Meyer Fueling h'ncilio, Pr(jecl 02008-117 Health Administration (OSIIA) and American Petroleum Institute (At']) or other requirements. Based on OSHA regulations, the upper fill classifies as a Group C soil and glacial till would be classified as Group A soil. Accordingly, for excavations more than four feet but less than 20 feet in depth, the temporary side slopes should be laid back pith a mininnum slope inclination of 1%::1 (Horizontal: Vertical) in the upper fill and'/,:I (11: V) in glacial till. Following excavation, all exposed slopes must be covered with reinforced plastic sheeting that is securely anchored to the slope face. This sheeting will contain loose soil conditions that may develop on the slope face and ravel off, therefore, preventing erosion of the slope face during periods of precipitation. If there is insufficient room to complete the excavations in this manner, temporary shoring will be required. 4.4 U nderermund Storage Tanks (IISTs) Riley understands that two USTs will be installed to the west of the canopy. The installation of the USTs will require an excavation of up to 20 feet bgs. The USTs can be installed in a single excavation. The depth to the top of the UST is typically three fleet below finished grade with at least 2 feet of appropriate backfill material. The backfill can be either pea gravel or other material per American Petroleum Institute (At']) specifications for setting the tanks. Based on the groundwater condition, minor to moderate groundwater seepage will be expected during excavation. The amount of groundwater seepage should be minor if the construction occurs in dry season. In our opinion, conventional sump pumps and ditches should be adequate to control the groundwater. 'I he US"r system installation and design must be in accordance with AN regulations. The installation design will require tank hold clown slabs to accommodate possible buoyant forces. 43) Slab-ou-Grade Construction With site preparation completed as described in the Site Preparation <aid Grading section, suitable support for slab -on -grade construction should be provided. Riley recommends that slab -on -grade construction be supported on existing fill or native soil. hnnlediately below the floor slab, we recommend placing a liar -inch thick capillary break layer of clean, free - draining sand or gravel that has less than five percent passing the No. 200 sieve. This material will reduce the potential for upward capillary movement of water through the underlying soil and subsequent wetting of the floor slab. Where moisture by vapor transmission is undesirable, an 8 to 10-mil thick plastic membrane should be placed on a 4-inch thick layer of capillary break. The membrane should be covered with I to 2 inches of clean, moist sand to guard against damage during construction and to aid in curing of the concrete. The Riley Group, Inc.