2001 Geotechnical Evaluation Report

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RVC Homes Project BABX-01-0124 April 12, 2001 Page 7 C.4.e. Frost Protection. In heated areas, we recommend the perimeter pile caps and grade beams extend a minimum of 3 1/2 feet below exterior grade for frost protection. Interior pile caps and grade beams may be placed immediately beneath the slab unless foundation construction will take place during the winter. During winter construction, pile caps and grade beams should be placed a minimum of 5 feet below grade to be protected from freezing. In unheated areas, we recommend the pile caps and grade beams also be placed a minimum of 5 feet below grade. C.4.f. Settlement. We anticipate total and differential settlement of the piles will be less than 1/2 inch and 1/4 inch, respectively, under the assumed loads. C.4.g. Concrete Fill. We recommend the piles be filled with concrete. This will increase their stiffness and load carrying capacities, and aid in maintaining the pile strength if the steel shell partially corrodes. We recommend the concrete have a minimum 28-day compressive strength of 2,500 pounds per square inch. C.5. Pile cap, Grade Beam and Foundation Wall Backfill To minimize the risk of excessive negative loading on foundation walls, pile caps and grade beams due to consolidation of the underlying soft, loose or organic soils, we recommend backfill placed around these structural elements consist of poorly graded sand with less than 5 percent passing the number 200 sieve. This material should extend a minimum of 2 feet away from the backfilled building elements. A 1-foot thick layer of clayey topsoil, slab, or pavement should cap the granular backfill at the surface. C.6. External Features Due to thick deposits of soft organic soils, it is likely the ground surfaces at the site will settle continually, however, the rate of settlement should decrease with time. The amount of settlement can be reduced by minimizing raises in grade. We recommend external features be designed to tolerate continual settlement of the general area surrounding the house. Driveway aprons and sidewalks should be hinged at the structure to prevent development of tripping hazards. These items should be structurally designed. Connections of the underground utilities should be made flexible. especially at the house connection.