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09/09/2013 Impact: Impact 15-4: Settlement and Foundation Movement The project's preliminary geotechnical studies determined that structural loads imposed by buildings more than approximately three stories in height would likely exceed the bearing capacity of either fill or weakly consolidated Bay mud underlying conventional shallow foundations. Such buildings would potentially experience gradual but excessive long-term total and differential settlements. Mitigation: Mitigation 15-4. The detailed, design-level geotechnical investigations required under Mitigation 15-1 for each project construction phase shall include a thickness and consolidation analysis of all clay soils underlying proposed building locations. This analysis shall be sufficient to accurately estimate the rate and total amount of consolidation expected to occur in response to building construction, as well as the likely magnitude of differential settlement. Building foundations, surface improvements, and utility connections shall be designed to structurally withstand the associated movement, without disrupting either pedestrian or vehicular connections to the building. The requirement described in Mitigation 15-1 for peer review of the recommended design-level geotechnical investigations, as well as for certification by the project civil engineer that all provisions of the investigation have been incorporated into the project's design and construction, would also apply to this mitigation and to all subsequent geotechnical and soils mitigation measures set forth in Draft EIR chapter 15 (Geology and Soils). Finding: Implementation of Mitigation 15-4 would reduce the potential compressible soil and settlement impacts to a less-than-significant level. Facts in Support of Finding: Implementation of Mitigation 15-4 would reduce potential compressible soil and settlement impacts to a less-than-significant level by requiring detailed, site-specific geotechnical investigations and solutions prepared by a registered engineering geologist or geotechnical engineer, with review and approval authority by the City Engineer. These facts are described in Draft EIR chapter 15 (Geology and Soils) on pages 15-1 through 15-15, which is hereby incorporated by reference. Impact: Impact 15-5: Expansive Soils. Near-surface clay soils subjected to seasonal cycles of wetting and drying can undergo significant volume changes, expanding when wet and shrinking when dry. Structures based in these materials would be subjected to significant stresses that could destabilize foundations and cause cracking or heaving of floor slabs and exterior pavements. Mitigation: Mitigation 15-5. The detailed, design-level geotechnical investigations required for each project construction phase under Mitigation 15-1 shall include an evaluation of the likely effects of building on expansive soils and shall recommend specific measures designed to minimize soil movement and/or counter its potentially destructive effects. Finding: Implementation of Mitigation 15-5 would reduce the potential expansive soil impacts to a less-than-significant level. ATTY/RES0.2901/STANFORD EIR CERTIfICATION RESO.#15294 REV:09-10-13 VR MUFF#100 Page 19 of 55