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Project No. 364 571 Page 4 Based on our analyses, we recommend that 30-foot-long, 60-inch-diameter dr/lied piers be designed for the following max/mum bending moment and shear: Maximum bending moment = 2455 foot&ips Depth below top of pier to maximum bending moment = 3.0 feet Maximum shear -- 133.8 kips at a depth of 22 feet Lateral deflection of the pier head during the design loading of 25 kips is estimated to be approximately 1/2 inch. Groundwater is not anticipated during excavation of the drilled pier foundation. A tremie pipe should be used to place concrete so as to prevent the concrete from hitting the side walls of the excavation. The tremie pipe should be equipped with a water tight valve at its lower end to prevent contamination of the first charge of concrete in case some groundwater seepage does enter the excavation. The lower end of the tremie should be kept embedded in the fresh concrete throughout the pour. Free fall of the concrete should not be allowed. Switch Building Foundation It is our opinion that the switch building can be supported on a shallow footings provided that the building pad is prepared as recommended below. We recommend that the switch building area be dearer of vegetation and organic debris and the unsuitable material hauled off the site. A minimum depth of removal of 12 inches is recommended. Any excavation remain/rig from removal of tree root bails should be cleaned of loose soil and debris and backfilled w/th properly compacted structural fill, Any new fill placed in the building pad area should be imported sand or gravel containing less than 5 percent particles passing the No. 200 sieve. The imported materials should be wetted or aerated as needed, and then compacted to at least 95 percent of the maximum laboratory dry demity determined in accordance w/th ASTM Test Method D 698. A qualified geotechnical consultant should observe the building pad preparation and test the compacted fill prior to constructing footings. We recommend that spread or continuous footings be designed for a maximum allowable soil bearing pressure of 2,000 psi (dead plus live loads), The footings should be founded at least 18 inches below the lowest adjacent rough grade and should be at least 12 inches wide. All footings should be reinforced in accordance with the structural engineer's recommendations. The building floor slab should be supported on at least 6 inches of clean, crushed aggregate (3/4-inch minus).