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T~e Pioneer Engineering Corporation <br />Project No: S97-0124 <br />06/09/97 <br /> Page No: iii <br /> <br />footing base. Pin piles are driven to a particular depth using a particuhr driving energy and <br />corresponding refusal criterion based on the recommendations provided by a geotechnical engineer. <br />All pin piles can be easily proof-loaded in the field for vertical compression capacity. <br /> <br />Based on the results of our analyses, we provide following installation recommendations for pin piles. <br /> <br />Pile type: Grade A steel, SCH 40 and SCH 80, galvanized <br /> <br />Pile diameter: 3-inch nominal (SCH 80) along fill slope crest and 2-inch nominal (SCH40) for all other <br />locations <br /> <br />Pile spacing: Maximum 2 feet on center for 3-inch nominal (SCH 80) diameter piles along fill slope <br />crest and 6 feet on center for 2-inch nominal (SCH40) diameter piles at all other locations <br /> <br />Estimated pile depths: 10 to 20 feet below existing grades <br /> <br />Critical locations: Install piles at all stress points including all building corners, individual columns, <br />and any other isolated stress points. <br /> <br />Required working vertical compression capacity: 3 kip based on estimated maximum footing <br />pressure of 500 psf over 6-foot interval. Estimated footing load is roughly 200 psf. <br /> <br />Required factor of safety: 2.0 <br /> <br />Installation and Proof-loading: Ail piles should be installed and proof-loaded to 6 kips vertical <br />compression capacity in the presence of a geotechnical engineer. Piles can be installed and proof- <br />loaded using a backhoe having a minimum static weight of 20,000 lb. We recommend that a <br />geotechnical engineer should inspect the installation of pin piles and examine all excavated footings to <br />verify subgrade soil conditions. A geotechnical engineer must approve pin pile depths and compression <br />loading capacities. <br /> <br />Option II: Daylight basement and/or stepped footings <br /> <br />The proposed structure can be placed on conventional shallow spread footings bearing on native <br />subgrade present at depths of 2 to 11.5 feet. These footings will consist of stepped footing pads with <br />stem walls and a foundation retaining wall as a southern building wall. Footings should be at least 12 <br />inches wide. Footings can be designed using up to 1,000 psf net maximum allowable bearing capacity. <br /> <br /> <br />