10730 19TH AVE SE 2018-01-02 MF Import

. W. T. Duryea Company JN 87105 May 28, 1987 Page 3 that it is intended to regzade the existing fills and to use ' some of this fi.il as structural fill in the building area. This ' fill at the test pit location was from a glacial till deposit and can be used as structuzal fill under the proper moisture conditions . The fill overlies a significant topaoil layet. Any soil contaminated with organic soil or wetter than the optimum requized for compaction should not be used as structural fill. Glacial till soils generally contain 25 to 35 pezcent silt and, thus, aze verp moisture sensitive. The best time for site grading activity is in the dryer summer months. The site may be gtaded in wet weather , but on-site soils then could not be used as fill and greater amounts of .select imported fill would be required . S� FOUNDATIONS � The proposed structure may be supported on cnnventional continuous and spread footings bearing on the weathered till soils underlying the topsoil oz on structural fill placed above inorganic native soils . Fill placed under footings should extend outwards from the edge of the footings at least an amount equal to the depth of fill underneath the footings . Exterior footings should be bottomed at a minimum depth of twelve (12) inches below the lowest adjacent outside finish grade. Interior footings may be at a depth of twelve (12) inches below the top � of the slab. Footings founded on weathered till soils or structural fill may be designed for an allowable soil bearing capacity Qf twenty-five hundred (2500) pounds per square foot (psf) . Footings beating on dense glacial till soils may also be designed fos a bearing pressure of five thousand cseee� psf . Continuous and individual spread footings should have minimum • widths of twelve (12) and eighteen (18 ) inches , respectively. A one-third increase in the above bearing pressures may be used when considering short term wind or seismic loads . For this design criteria, it is anticipated that total settlements of footings founded on weathered till soils and on fills less than five (5) feet thick will be about one-half inch. Foundations on weathered till soils should experience negligible settlement. Almost all settlement due to dead loads from the building structute should occur during construction. Lateral loads due to wind or seismic forces may be resisted by friction between the foundations and the supporting compacted fill subgrade or by passive earth pressure on the foundations . For the latter, the foundations must be poured "neat" against the existing soil or backfilled with a compacted fill meeting Cti07'FCH CONSULTANTS INC.