4711 GLENHAVEN DR 2016-01-01 MF Import

V ] January 15, 1998 Project No. G97246A III. PRELIMINARY DESIGN RECONII��NDATIONS 8.0 INTRODUCTION Our exploration indicates that, from a geotechnical standpoint, the parcel is suitable for the proposed residcntial development provided the risks discussed aze understood and accepted by the owner and the geologic hazard mitigation and geotechnical recommendations contained herein are properly followed. The foundation bearing stratum is located at a relatively shallow ' depth in the lower por..'�� of the site and spread footing foundations may be utilized. VJe understand that the distribution of foundation loads of the three-story daylight basement, wood-frame building will be rypical; no heavily concentrated loads are anticipated. ' Consequently, the site's medium dense, silry sand soil will be capable of providing suitaUle foundation support. The loose fill soils which mande the steep slope adjacent to Glenhaven Drive will not provide suitable support for the concrete retaining walls proposed for the upper parl:ing area. Themfore, we recommend that d�ese walls be supported upon drilled piers extending dirough the fill and into the underlying natural soils. Our specific recommendations concerning site preparation and grading, and foundation support of d�e proposed residence and associated retaining walls are presented in the following sections of this report. 9.0 SITE PREPARATION Site preparation of planned build'uig areas should include die removal of all vegetadon. Addi[ionally, any organic topsoil should be removed and the remaining roou grubbed. Subsequcntly, excavations required achieve the proposed building subgrade elevation can be completed. Loose fill and natural soils are not suitable for foundation support. These soils sliould be svipped from the foundation area. Our exploration pits found that these soils extend to depths of apF;roximately 4 fee: below existing grades within the proposed building azea. The foundation excavation will require cuts of 2 feet in depth near the northwest comer of the building, and up to 12 feet in depth along die south footing line, exposine medium dense to dense bearing soils. Therefore, most of the unsuitable loose soils will be removed from [he building footprint during site excavation. The northeast corner of the residence will require placement of fill soils r�ngine benyeen 3 to S feet in depth. Prior to placement of any fill soils, we reconuncnd diat the upper 2 Ceet of die exis[in� loose natural soils be excavated, die basc of the esca��ation compacted, and the excavatcd material replaced as structural fill. S