15 ATTACHMENT 9 - Laserfiche WebLink

Project No. 9929.G Geotechnical Investigation/Vineyard Avenue, Pleasanton 8 August 2003 42. A minimum of two inches of wetted sand should be placed over the vapor barrier to facilitate curing of the concrete and to act as a cushion to protect the membrane. The perimeter of the slab should be thickened to bear on the prepared building pad and to confine the sand. During winter construction, sand may become saturated due to rainy weather prior to pouring. Saturated sand is not desirable because there exists a high probability of creating sand pockets within the slab section during the concrete pour. As an alternate, a sand-fine gravel mixture that is stable under saturated conditions maybe used. However, the material must be approved by the Soil Engineer prior to use. 43. Slabs maybe constructed at pad grade. The perimeter of the slab should be thickened to bear on the prepared building pad and to confine the sand. 44. Any concrete flatwork such as steps, patios, or sidewalks should be designed independently of the slab. Waterproof joints should be provided between the flatwork and the structural unit. We have provided herein recommendations for a pier and grade beam foundation system. The following foundation recommendations are contingent upon adequate surface drainage being constructed as recommended in this report as designed by the project Civil Engineer, and maintained by the property owners at all times. Piers and Grade Beam Construction 45. The piers should have a minimum diameter of twelve (12) inches and extend to a minimum total depth of 10 feet below the pad grade, or three feet into native material, whichever is deeper. The actual depth of all piers will be determined in the field by the Soil Engineer. 46. The piers should be designed for an allowable skin friction of 500 p.s.f. for dead plus live loads below a depth of two feet measured from rough pad grade. This value maybe increased by one-third to resist short-term wind and/or seismic loads. The grade beam should be designed for an uplift pressure of 500 p.s.f. To resist uplift, the dead load of the structure and an allowable adhesion value of 400 p.s.f. acting along the length of the pier (neglecting the top 2 feet of TERRASEARCH, inc Page 23 of 53