Laserfiche WebLink
The Pioneer Engineering Corporation <br />Project No: S97-0124 <br />06/09/97 <br /> Page No: ii <br /> <br />deposit is known to extend to several tens of feet in depth. <br /> <br />Groundwater - We did not encountered groundwater table in our SPT boring. We noticed very moist <br />soil samples below 12 feet. <br /> <br />Design Recommendations <br /> <br />Based on the results of our study, we believe the site is suitable for proposed development, provided <br />following recommendations are followed. <br /> <br />Foundations <br /> <br />As indicated earlier, the site is underlain by roughly 2 to 11.5 feet of old fill having consistencies of <br />medium stiff to stiff. There are no records of old fill placement and compaction monitoring activities. <br />Due to inherent non-homogeneons characteristics associated with any uncontrolled fill soil stratum, <br />there is a potential for the presence of boulders, construction debris, or any other non-soil materials <br />even though we did not encounter them in our boring. Moreover, fill depths increase from 2 feet near <br />northern site boundary to 11.5 feet near southern boundary of proposed building pad. <br /> <br />Considering the inherent non-homogeneous characteristics associated with fill soil stratum, and the <br />presence of variable depths of fall under the proposed building area, we believe there is a moderate <br />potential for post construction differential settlements. In addition, there is a potential for slope <br />instability due to un-benched fill placement over original native subgrade. Therefore, we recommend <br />following two foundation support options. <br /> <br />Option I: Shallow-Deep Foundation System <br /> <br />In our opinion, this foundation system is the most cost-effective solution for fill situation at the site. <br />Such a system typically consists of a conventional shallow spread footing partially supported by soil and <br />partially supported by 2-inch to 4-inch diameter galvanized steel pin piles. Typically, first 18-inch <br />deep footing trenches are excavated to expose the foundation subgrade and then pin piles are driven <br />into the subgrade at a particular spacing. At least 3 inches of pin pile is embedded into the shallow <br /> <br /> <br />