2011-12-06_REVISION - M2009018 (52)

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2. Based on the presence of soluble sulfates, a Type II or Type V cement should be used for all concrete exposed to the soils or bedrock. Also, a maximum water - cementitious material ratio of 0.50 along with a minimum compressive strength of 4,000 p.s.i. is recommended. 3. The bottom of all foundation components should be placed a minimum of 30 inches below finished grade for frost protection: 4. The completed open excavation should be observed by an experienced Soils Engineer or technician from our office, to confirm the subsurface conditions described in this report and observe any variations which may affect construction at the site. 6 SITE GRADING, LANDSCAPING & DRAINAGE Every precaution should be taken to prevent wetting o f the foundation subsoils and the percolation of water in the backfill zone or other areas that may reach the foundation elements. Water infiltrating near the foundation may result in architectural or structural damage due to consolidating or swelling of the subsoils. The soil design criteria assumes that historic soil moisture content will be maintained. Backfill around the outside perimeter of the structure should be compacted at optimum moisture, or above, and to at least 90 percent of standard proctor density as determined by ASTM Standard Test D -698. A suggested specification for placement of back fills is included as Appendix A. Back fill material should be relatively impervious and non - swelling. The backfill should be free of frozen soil, large dried clods, and organic matter. Backfilling should only be accomplished when concrete strength and adequate support to foundation walls (if used) are applied and acceptable to the Foundation Engineer. It is our opinion that the natural soils at the site could be used for backfill material. Finished grades should be sloped away from the structure on all sides to provide positive drainage.