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Project No. 9929.G Geotechnical Investigation/Vineyard Avenue, Pleasanton <br />Allowable Bearing Pressure <br />Edge Moisture Variation Distance (em) <br />Differential Soil Movement (ym) <br />8 August 2003 <br />Swelling Mode <br />Center Lift Edge Lift <br />1,500 psf 1,500 psf <br />5.0 feet 2.5 feet <br />3.2 inches 0.7 inches <br />The above design values are based on the following soil and climate parameters: <br />Parameter <br />Thornthwaite Moisture Index (Im) <br />Predominant Clay Mineral <br />Percent Passing #200 Sieve <br />Plasticity Index <br />Depth to Constant Suction <br />Soil Suction (pF) <br />Moisture Velocity <br />Estimated or Assumed Value <br />-20 <br />Montmorillonite <br />70% <br />20 <br />5 feet <br />3.6 <br />0.7 inches/month <br />39. Design criteria for post-tensioned slabs on less expansive on-site soils, bedrock or select <br />import fill, if necessary, can be provided once the properties and thickness of the select import <br />layer are known. <br />General Construction Requirements for Structural Mat &Post-Tensioned Slab <br />40. The near surface soil is low to moderately expansive and therefore the slab subgrade should <br />be soaked to saturation (minimum 5% above optimum) to a depth of 18 inches prior to placement <br />of the sand and Visqueen. This should be verified and approved by the Soil Engineer. The <br />penetration of a thin metal probe to a depth of 12 inches generally indicates sufficient saturation. <br />41. A Visqueen-type membrane at least 10 mil thick should be placed between the prepared <br />subgrade and the slab to provide an effective vapor bamer, and to minimize moisture <br />condensation under the floor coverings. The vapor barrier membrane shall be lapped adequately to <br />provide a continuous vapor proof barrier under the entire slab. Care must be taken to assure that the <br />membrane does not become torn and entangled with the reinforcing. <br />TERRASEARCH, inG Page 22 of 53 <br />