10-26-1994 Council Agenda - Laserfiche WebLink

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Page I'(1r «'c nnticipate the structure would be constructed using above grade wood framing and would ordinarily utilize below grade masonry block foundation walls or cast -in -place concrete foundation wall construction. For this type of structure on minimum width footings. the actual soil contact pressures would not exceed about 1500 -1300 psf. Discussion - Review of the test borings indicates that in general. conditions are favorable for planned construction of a house. However, the borings do indicate the presence of inferior surficial soils to depths of 1. lo 6' at the boring locations. After removal and replacement of these soils. it is our opinion that spread footing construction can be performed either supported by the undisturbed natural soils or imported engineered fill. Although the actual static water table should be well below the surface at this lot, it is possible that the perched water condition detected by the borings may have an impact on the construction. nu i, 1 d i nr' Grad ijig _ltecommendat ions - We recommend that the existing fill or topsoil layer he removed from below the proposed house and garage area. Excavation should include any soft pockets of clay exposed below the fill /topsoil. Thus. the excavation should expose the underlying naturally deposited brown sandy lean clay till soils depicted by the borings at depths of 1' to 6' at the boring locations. The actual depth of excavation required may vary throughout the site. Therefore. some budges contingencies should be provided for possible additional excavation'. The excavation should be done carefully in order to minimize disturbance of the bearing soil. It may be necessary to perform the excavation into the clay soils using a backhoe. Where the excavation extends lower than foundation grade. the edges of the excavation and resulting fill should be oversized from the Planned outside edges of the foundation. by a distance at Least equal to the depth of fill required below the footing at that location 1i.e., 1:1 lateral oversize). After the excavation to final grades is performed, the exposed natural soils should be observed by a geotechnical engineer and fudge for suitability prior to placement of fill or footings. Page 51