Subsurface exploration info-1994

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� SUBSURFACE EXPLORATION LOT 2, BLOCK 1 KELLY 2nd ADDITION ORONO, MINNFSOTA ALLIED No. 94117 negative skin fricdon, (downdrag), would be transferred to the piles as a result of the weight of the existing and planned fills and consolidation of the existing weak soils. Our computations indicate that piles driven to a depth of 45 feet below grade, at the location of SPT-4, would attain a safe working load of 35 tons per pile with a minimum factor of safety of 2.5. Based on pile driving to that depth, the net working load per pile would then be 20 tons. That would be the load capacity available for structural support of the building. The timber piles should conform with the requirements of MN/DOT specification 3471. The piles should be furnished and installed in accordance with the construction requirements of MN/DOT 2452. The pile driving work should begin with a test pile. Driving records should be maintained for all piles in order to facilitate computation of capacities using a suitable pile driving formula. Once the test piles have been driven and judged suitable, the remaining piles may be installed. To attain a working load capacity of 35 tons per pile, we recommend the piles be driven with a hammer having a manufacturer's rated energy on the order of 17,000 to 21,000 foot-pounds. There will be some loss of grade around the exterior of the residence during the lifetime of the structure. We suggest that this setdement be considered in the installation of the utilities. The utilities should have fle�cible connections to the house so that the settlement does not result in the shearing off or damage to the utilities. A structural engineer, registered to practice in the state of Minnesota should be retained for the design of the pile cap and grade beam system. 6