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M98168GE . • embedment in the formational material to a depth of at least one and one-half (1 1/2) pier diameters into the formational material. The bottom of the pier holes should be cleaned to insure that all loose and disturbed materials are removed prior to placing pier concrete. Because of the rebounding potential in the formational materials when unloaded by excavation and because of the possibili- ty of desiccation of the newly exposed material we suggest that concrete be placed in the pier holes immediately after excavation and cleaning. If the piers are designed and constructed as discussed above we anticipate that the post construction settlement potential of each pier may be less than about one quarter (1/4) inch. The portion of the pier above the formational surface and in the weathered formational material should be cased with a sono tube or similar casing to help prevent flaring on the top of the pier holes and help provide a positive separation of the pier concrete and the adjacent soils. Construction of the piers should include case to prevent flaring of the top of the piers. Preventing flaring may be aided by casing the drilled pier excavation with a sono tube or similar casing. Reducing flaring is to help reduce the potential of swelling soils to impose uplift forces which will put the pier in tension. The drilled piers should be vertically reinforced to provide tensile strength in the piers should swelling oii site soils apply tensile forces on the piers. The structural engineer should be consulted to provide structural design recommendations. Grade beams between piers should be provided with void spaces between the soil and the grade beam. The grade beam should not come in contact with the soils. Separation is to help reduce the potential for heave of the foundations should the soils swell. Free ground water was not encountered in the teat borings at the time of the field study. We anticipate that fractured layers may exist in the formational material and that the fractured layers may carry or store water. If ground water is encountered, the pier holes should be dewatered prior to placing pier concrete. No pier concrete should be placed when more than six (6) inches of water exists in the bottom of the pier holes. The piers should be filled with a tremie placed concrete immediately after the drilling and cleaning operation is complete. 9 ~iambert ana ~,ooociateo WNWlTINO OEOTlCNN,C~I fMOIM{{p ENO YAtMI~I ~ESTNIO