7200 HARDESON RD 2016-01-01 MF Import

� �� � ai CNA Architecture Group 1£ April 1991 .� W-7352 Page 9 5.3 Shallow Foundations It is our opinion that shailow, isolated or cuntinuous spread footings founded within undisturbed native soils and/or compacted structural fill placed above the medium dense native deposits would provide suitable foundation si�pport for the proposed development. Prior to footing construction, the site should be prepared by stripping, prerolling and/or structural fill placement as outiined earlier. An allowable soil bearing pressure of 3,000 pounds per square foot (ps� may be utilized for design of shallow footings founded in the medium dense natural soils or properly compacted structural fill. No footings should be founded in or above any topsoil, undocumented fill, or loose native soils. These allowable bearing pressures may be increased by up to one-third to accommodate transient or seismic loads. The base of exterior footings should be located a minimum a depth of 18 inches below adjacent grade or top of floor slab, whichever is lower. Interior footings should penetrate at least 12 inches beiow surrounding ground or slab level. We recommend that all footings have a minimum dimension of 18 inches. If the footings are constructed above structurai fill, the base of the structural fill pad should extend laterally outside the edge of the foundation, a distance equal to the thickness of the structurai fill layer beneath the footing. This will require that excavation of existing fill extend outside the buiiding limits on a 1H:1V slope down and out to the native soils. Foundation settlements will be closely related to the quality of the earthwork performed on the site. Assuming moderate loading, and fill placement according to the referenced specifications, we estimate that total settlement of the foundation elements placed on the properly prepared native soils or structural fill should not exceed one inch, with differential settlements of approximatel 3/a ch or less. Due to the anticipated structural fiil thickness, abrupt differential settlemen is not expected. However, it should be noted that actual settlements could increase if care is not exercised during fill piacement and/or foundation construction. We recommend that footing excavations be observed prior to placement nf concrete by a representative from our firm to observe that the bearing soils are undisturbed and compacted consistent with the recommendations within this report. << .; ;