2616 BAKER AVE 2018-02-01 - Laserfiche WebLink

- • • Geotechnical Reconnaissance 2616 Baker Avenue Everett, Washington August 28, 2015 Excavation and Footin�s The proposed perimeter and interior strip footings should be supported on native undisturbed glacial soil. We anticipate that the existing site might be underlain by about 2 to 3 fect of undocumented fill or loose soil. Conventional spread footings should either be supported on competent soil beneath the fill or on compacted fill. All footings must be supported in native undisturbcd soil or compacted fill. We recommend using an allowable bearing capacity of 2,000 psf for design of footings supportcd on thc native, undisturbed, medium dense, silty SAND or compacted fill. Lateral resistance for footings may be calculated at 300 pcf per foot of overburden. The coefficient of friction bctween the footing and the soil can be calculated as 0.4. The footing area must be free from loose or wet soil prior to placing reinforcing or pouring concrete. The geotechnical engineer should vcrify the bearing. If native undisturbed soil is not encountered in the uppermost 30 inches of excavation then we recommend the following measures to improve the subgrade prior to pouring the footings: • Remove all organic-rich soil to expose the silty SAND soil. Depth of the footing shall be at least 30 inches below existing grade. • Compact the exposed subgrade with a vibratory compactor such as a jumping jack tmtil it achieves a firm unyielding condition. The soil must be properly moisnire conditioned to achieve compaction. If it is too dusty, sprinkle with water briefly. If the soil pumps, bringing water to the surface, dry thc soil before compacting or add Portland eement to the soil to dry the subgrade. • The footi�lg n�ay be pourcd directly against the soil or onto compacted 5/8'"-0" crushed rock. Thc rock laycr shall not cxceed 6 inchcs in loosc thickness for compactio�� witll a jumping jack. Footings may bc pourcd neat against the trench or formed. • The support for the posts or framing should bc brotight to the surface by means of a reinforced concretc stem wall integrated into the footing witl� proper reinforcing. Reinforci►1g for the stem wall and connections for the posts shotild be provided by the structural engineer. Temporarv Exccn�crtions Prior to excavating for the footings the existin�building should bc supported on temporary cribbing and beams or by other means. Excavation for the site appears to be limited to rather shallow excavations for conventional spread footings. Excavations decper than 3 feet should be shaped at 1 H:1 V to prevent sloughing and to protect workers in the excavation below. The coi�tractor should take appropriate mcasures to protect workers in excavations that are deeper than about 4 feet depth. The protection of thc workers and maintaining safe excavations shall be thc ongoing responsibility of the general contractor. / 1841 Geo Letter Report 4 �1� The Galli Groa�p