4602 SEAHURST AVE 2018-01-02 MF Import

Geotechnical Design Parameters 95.1"5 Dynasty Homes site March 9, 1998 ■ Lateral seismic acceleratlon value for use In = 0.20g design ■ 1997 UBC Seismic Zone 3 zone factor, Z 0.30 ■ 1997 UBC Site Soil Profile Type So a Seismic Coefficient C, 0.36 ■ Seismic Coefficient C, = 0•54 Page 4 It is crucial to carefully and thoroughly redensify all of the In -place soil materials beneath the building floor slab footprints. All structural fill shall be compacted to at least 95% of the materials maximum dry density, as determined by ASTM D-1557-91 (Modified Proctor). The fill should be placed In lifts of no more than ten (10) Inches loose thickness for mechanical compaction equipment and four linches for hand operated compaction equipment. It Is also critical that any fill placed over a sk"V surface with a gradient of steeper than 4HAV be carefully benched Into the sloping surface. Any bench must beat least six feet wide and should be inclined sightly back towards Ova body of the slope to promote drainage and to provide some additional resistance to sliding. The majority of the in -place st ,Is are generaNy granular in nature, but are predominantly fine grained In nature (slit and day sized partldes passing the number 200 mesh sieve). Because of this, they are considered to be moisture sansltive. If they become wet it Is likely that it will become difficult, If not impossible, to work and compact them In - place. If earthwork is performed in wet weather, It may also be necessary to use a geotextile to separate the native sails from the new fill. We recommend that a Miret, 500X, or an equivalent approved in writing by the geotedmriical engineer, be used fur this purpose. This geotextiie must be installed in strict adherence wkh the manufacturers specification or any warranty or guarantee could be voided. Based on the nature and apparent density of the In -situ soil, the lack of a shallow groundwater WM that could surge durkp an earthquake and saturate the shallow sails, and the overall grain size distribution of the materials, ft is our professional opinion that the risk of these soils being subject to any significant degree of liquefaction during a severe earthquake is low to negligible. 50'd 4b:9T 966T-W-E0