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_ s � Project No. JB-20100 4 December 2000 Page 5 and resulting cracking/distress. Recommendations to help reduce the movement of the foundations and concrete slab-on-grade floors/flatwork are discussed in later sections of this report. 4.2 Geotechnical Hazards Risk of geotechnical hazards will always exist due to uncertainties of geologic conditions and the unpredictability of seismic activity in the area. However, in our opinion, based on available data, there are no indications of geotechnical hazards that would preclude use of the site for the proposed development. The proposed structures should be designed to meet current Uniform Building Code (UBC) requirements to limit potential damage from ground shaking. 5.0 RECOMMENDATIONS 5.1 Earthwork 5.1.1 General Final grading plans were not available during preparation of this report. We • recommend that final grading plans be reviewed by our office prior to starting the grading operations. As previously discussed, results of the subsurface site investigation indicate _ the existing near-surface soils are loose and could be subject to adverse settlement. These near surface soils are not the best material for support of foundations, floor slabs, and exterior flatwork/sidewalks in their present • state. To reduce the potential for adverse settlement, we recommend these subgrade soils be over-excavated a minimum of 2 feet below the planned _ footing elevation and replaced with moisture-conditioned, compacted fill in the foundation areas and at least 5 feet beyond the structure and exterior flatwork/sidewalk areas in plan view, if practicable. If compacted engineered fill is to be placed in these areas as part of the site grading, the depth of over-excavation may be reduced by the thickness of the fill. Deeper sub- excavation may be required depending on soil conditions encountered during grading. Figure 11, Foundation Materials Under Building, presents the details for over-excavating and replacing the soil with compacted, engineered fill within the building limits. Compaction recommendations are discussed in Section 5.1.4 Fill Placement and Compaction. 1 5.1.2 Site Clearing All grading must be observed by our representative. It is especially ®Korbmacher Engineering, Inc.