Reso 2002-070 - Laserfiche WebLink

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Geotechnical Report Identify and summarize any special geologic conditions, including, but not limited to, compressible and expansive soils, tunnels and mine shafts, unstable slopes, active seismic zones, excessive ground water and areas prone to liquefaction. Indicate if these conditions will prevent the use or significantly increase the cost of developing the site for a public library building. A geotechnical report was prepared in April 2002 by a qualified consultant, Kleinfelder, Inc., to describe the subgrade conditions of the project site and evaluate any geologic or seismic hazards. The investigation consisted of field exploration, laboratory testing, engineering analysis, and design recommendations. The report concluded that the site is suitable for the planned library as there were no unusual geologic hazards found. The main engineering concern is the presence of moderately to highly expansive soils which are commonly found in the San Francisco Bay Area and can be mitigated through conventional design and construction methods. These soils are prone to shrink or swell due to changes in moisture content which, if not mitigated, could cause unacceptable levels of settlement beneath a structure. To mitigate this soil condition, the report recommended the slight Beeping of foundations, importing of non- expansiveengineered fill or lime treatment of these soils beneath the building, as well as insuring that surface water is drained away from the building. According to information provided by Kleinfelder, Inc., the site is not located within an Alquist-Priolo Earthquake Fault Zone, where special studies addressing the potential for surface fault rupture are required. The closest fault considered capable of rupture is the Hayward fault, located approximately 4 kilometers east of the site. There are no particular seismic hazards at the site other than the potential for strong ground shaking, which is typical in the San Francisco Bay Area. There are no geologic hazards such as unstable slopes, excessive groundwater, tunnels, shafts, or areas prone to liquefaction. Demolition Describe any necessary demolition of structures and the associated costs involved with the site. (If no demolition, indicate by "N/A") Structure(s) to be Demolished 1. > Old library and parking 2. > Professional office building and parking lot 3. > 4. > 5. > 6.> Total Demolition: Demolition Cost Estimate $ 24,581 $ 52,022 $ 76,603 21