1318 37TH ST 2018-01-02 MF Import

Jarr.es Pirie ` JN 97072 March 18, 1997 Page 4 The native soils have poor drainage characteristics so using them for wall backfill involves a risk that some water may seep through walls. As a minimum, waterproofing should be provided where there will be below -grade, occupied spaces or moisture -sensitive areas, such as storage and mechanical rooms. In general, the more care and expense taken during the initial drainage and waterproofing installation, the fewer water problems that will develop later. Geotech Consultants, Inc. should be allowed to review the final development plans to verify that the recommendations presented in this report are adequately addressed in the design. Such a plan review would be additional work beyond the current scope of work for this study, and it may include revisions to our recommendations to accommodate site, development, and geotechnical constraints that become more evident during the review process. Conventional Foundations The proposed structures can be supported on conventional continuous and spread footings bearing on undisturbed, med;um-dense to dense, native soil or on structural fill placed above this competent, native soil. See the later sub -section entitled General Earthwork and Structural Fill for recommendations regarding the placement and compaction of structural fill beneath structures. We recommend that continuous and individual spread footings have minimum widths of 12 and 16 inches, respectively. They should be bottomed at least 12 inches below the lowest adjacent finish ground surface for frost protection. The local building codes should be reviewed to determine if different footing widths or embedment depths are required. Footing subgrades must be cleaned of loose or disturbed soil prior to pouring concrete. Depending upon site and equipment constraints, this may require removing the disturbed soil by hand. Depending on the final site grades, some overexcavation may be required below the footings to expose competent, native soil. Unless lean concrete is used to fill an overexcavated hole, the overexcavation must be at least as wide at the bottom as the sum of the depth of the overexcavation and the footing width. For example, an overexcavation extending 2 feet below the bottom of a 3-foot-wide footing must be at least 5 feet wide at the base of the excavation. If leant concrete is used, the overexcavation need only extend 6 inches beyond the edges of the footing. The following allowable bearing pressures are appropriate for footings constructed according to the above recommendations: Allowable Bearing Condition Bearing Pressure Placed directly on competent, 4,000 psf native soil Supported on structural fill placed 2,000 psf above competent, native soil Where: psf is pounds per square foot. GEOTECH CONSULTANTS, INC.