1802 W MARINE VIEW DR 2016-01-01 MF Import

consistency when subjected ta construction traffic or otherwise disturbed in an open excavation or in wet conditions. FOUNDATIONS We recommend that the circuit switcher be supported on a pile foundation to transfer the loads to the dense to very dense sand layer which was,encountered in our borings at approximately 27 feet below ground surface. We understand that the switcher will be supported on two pedestals and that the base of these pedestals shauld be at the ground surface. - i for the anticipated structural loads, we e�pect that treated timber piles wi1; be the most economical choice for pile support. Timber piles should conform to the size and quality requirements of ASTM D-25 Table 2. The piles should be cansidered to be end-bearing, and should be sized in accordance with ASTM D-25 Table 2 with a minimum tip diameter of 7 inches. We recommend that the foundation be supported on two piles driven vertically into the sand layer and spaced not closer than 9 feet from center to center. The estimated loads on each pile are 6,000 pounds vertical and 1,700 pounds horizontal with an overturning moment of 14,000 faot-pounds. This loading is • well within the typical loads imposed on timber piling of the size recommended. These piles should be tied together at the surface with a reinforced concrete pile cap onto which the circuit switcher will be attached. This cap should not allow any rotation of the pile head. A lateral load analysis indicates that with the imposed ]oads on the recommended piles, the lateral defornation should be less ihan 1/4 inch. The vertical settlement , should also be less than 1/4 inch. The potential for downdrag loads on pjles should be evaluated if any future substation expansions or additions are planned. Future changes such as lowering the groundwater table or an additional load near the piles could result in downdrag loads on the piles and an increase of the load on the pile tip. cor�r�e co�ra,n�m r�nv