Reso13 PC 13-09 2859 Initial Study Mitigated Negative Declaration Kensington

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Proposed Senior Assisted Living Facility PSI Project No. 575-308-2 August 3, 2011 Page 15 Based on the near surface soil encountered in the borings, it is our opinion that a modulus of subgrade reaction (k) of 130 pci is suitable, given the presence of the underlying base course. Based on this, we offer the following pavement recommendations: Light Dutv Section • 6 Inches Portland Cement Concrete • 4 inches Class II Aggregate Base Heavv Dutv Section • 6'/2 Inches Portland Cement Concrete • 4 inches Class II Aggregate Base For this design, a minimum 28-day compressive strength of 4,000 psi is recommended for the concrete. Joints for the concrete slabs should not exceed 15 feet for the light duty sections and 15 feet for the heavy duty sections. Proper load transfer should be provided across slab joints perpendicular to traffic, as deemed necessary by the project designer. The aggregate base course and the upper 12 inches of subgrade should be compacted to at least 95 percent of the material's maximum dry density. At the trash enclosure and entrance/exit areas, a minimum concrete thickness of 7 inches over 4 inches of aggregate base is recommended. The above recommended pavement sections represent minimum design thicknesses and, as such, periodic maintenance should be anticipated. Also, these recommended pavement sections should be confirmed or modified by your Civil Engineer, based on actual traffic and the owner's requirements. The pavement section materials and construction should comply with the Caltrans Standard Specifications and local municipality requirements. Where pavement areas are adjacent to heavily landscaping areas, we recommend some measures of moisture control be taken to prevent the subgrade soils from becoming saturated. It is recommended that the concrete curbing adjacent to the landscape areas extend into the prepared subgrade to reduce the potential for irrigation water to saturate the subgrade soils.