4805 BELVEDERE AVE 2016-01-01 MF Import

Su6surface Ecpiorntion, Geologic Na�ard, and Befvedere Lors Fast P�eliminary Geotechnical Engineenng Repon Evererr R'ashim m� Preliminarv Design_Recommendations I 1.2 Foundation Recommendations for Structures Located Between 20 and 40 Feet from the Top of the Str.cp Slope The risk of damage to the proposed structures by seismically induced landsliding is low, provided the recommendations contained in this report are properly followed. Our analyses indicate low factors of safety under seismic conditions for the area less than 40 feet from the top of the slope; however, the calculated downslope movement associated with landsliding 20 feet or more i:om the top of the slope is relatively minor. Two options for foundation support are recommended for structures sited between 20 and 40 feet from the top of the slope. The first option tiould be ro support these strucmres on comentional spread footings diat are deepened so that a horizontal distance of at least 40 feet is maintained between the base of the footings and the face ofthe stecp slope,to achieve an "effective setback" of 40 feet. Where placement of footings at sufficient depth to achicve the 40-foot effective setback is not practical, we recommend that foundation support be provided by driven pipe piles. Allowable axial capacities for driven pipe piles are provided in Table 3 below. Tablc 3 Summar}' of Allo�ti�able Pipe Pile Capacities Nominal Pipc �tinimum �Vall Minimum Allowable Axial Dinmetcr Thickncss Hammcr Size Ca acit � 4-inch Schedule 80 � 8501bs 16 6-in�— �ti –� ScheJule 80 2,OW Ibs 30 Driving Timc 16 15 In order for the stated pile capacities to apply, the pipe piles should be driven to rcfusal, whicli is defined as less th�n 1 inch of penetration during the specified period of continuous driving. The piles should achieve at least 5 feet of embedment into the very dense sand underlying the site. No lateral capacity would be provided by vertically installed pipe piles. Lateral capaciry could be attained through the usc of batter piles or passive resistance over the buried portions of the grade bcams. An AGSI representative must observe installation of all pipe piling. Combination sprcad fooiing/pipe pile foundations may also be utilized, provided the 40-foot effective setback is maintained. 5pread footings and pile caps should be connected with grade beams to fonn a rigid foundation. 11.3 Founda[ion Recommendations for Strucmres Located Between 0 and 20 Feet from the To � of the Stecp Slope 'I'hc risk of damage to the proposed strucmres by seismically induced landsliding is low, �ruvided the recommendations contained in �his report are properly followed. Our analyses ,A1arCh S, 20dJ ASSOCIATED EARTN SGENCES, 1NC. r:r:,: �r��,�r„n r.,��.��,��ato��:c��cr- u.�: Page 14