10008 25TH AVE SE 2016-01-01 MF Import

1. �� � 3.0 CONCLUSIONS AND RECOMMENDATIONS � Based on conditions observed in the explorations, construction of the project appears feasible � using standazd conswction equiprci:nt and methods. Geotechnical conclusions and recommendations are presented for seismic consideration.;,site grading, foundation suppoR, floor slab support,and drainage. �_) . 3.1 SEISMIIC CONSIDERATIONS � The project site is lo�ated within seismic Zone 3 as defned by the 1997 Unifortn Duilding Code (UBC). The following values may be used in the UBC based analysis of earthquake loads: seismic zone � factor Z=0.30; soil profile type S�, seismic ccefficient C,= 0.45 and seismic coefficient C,= 0.33. The design response spectra may be computed based on Figure l63 in the UBC. l t 3.2 SITE GRADING , Site grading is expected to consist of removing existing asphalt, stripping vegetation and topsoil, excavating for new foundations, subgrade preparation for 800r slabs, exterior grade backfill, and utility � trench backfill. Asphalt is not suitable for reuse and should be wasted offsite at an approveci localion. lVegetation and topsoit should be stripped from the addition areas. Based on our field explorations, we , estimate the stripping depth to vary from Y: to 2 feet. The limits of stripping should extend at least 5 ft 1 beyond the buildirg footprint. Stripped matetial is considered unsuitable for reuse as fill, but may be stockpiled and reused in landscape areas. If not reused, the material should be wasted off site at an ' approved location. -� Field explocations completed in the area of the building additions revealed the presence of fill � which may be present below proposed foundation depth. Fill will not provide proper suppoR of foundations, but will provide adequate suppoR for slabon-grade floors if properly recompacted. 1 Excavations for foundations should be extended to suitable bearing scil. A geotechnical engineer should observe the Coundation excavation to check that suitable native soil is present. If fill or disturt�ed native i soil is exposed at foundation subgrade, it should be overexcavated to expose undisturbed native soil. The _; overexcavation should extend laterally outward from the edges of the footing a distance equal to at least one-half the depth of the overexcavation. Overexcavations should be bacY.filled with structural fill as ' recommended in Section 3.3 of this report. Based on conditions observed in test pits excavated in 1989, overexcavation depths are expected ro range from 0 to 2 fi. , ..J JSIlBN7 I�PROJECT10110D50101EA5TMONT RPTDOC 3-I L�wonuHs50cUi�s /