7000 HARDESON RD 2018-01-02 MF Import

Quadrant 6-917-10260 12 April 1996 Page 5 subgrade soil. Foundations founded on compacted structural fill may be designed with a maximum allowable soil bearing pressure of 3,000 psf (pounds per square foot). The allowable bearing pressure may be increased by up to one-third to accommodate transient dynamic loads such as wind and seismic forces. Exterior footings should be located at least 18 inches below the lowest adjacent grades for frost protection. Interior footings need only extend 12 inches below slab level. We recommend that all continuous footings have a minimum width of Is inches, and isolated footings have a minimum dimension of 24 inches. We estimate total settlement of foundations founded in the prescribed bearing strata will be on the order of 1-inch or less. Differential settlement is estimated to be on the order of %-inch or less. Foundation settlement is often a function of how well the footing subgrade was prepared. Footing excavations should be free of loose or soft soils, slough, debris, or standing water prior to pouring footing concrete. No foundation element should be set in or above loose or disturbed soils, organic soils, or uncompacted fill. We recommend that the building be provided with a perimeter footing drain with clean -outs to collect available water for those portions of the building adjacent to landscaped areas. Footing drains are not necessary in areas where the pavement comes right up against the building. Footing drains should consist of a minimum 44nch diameter perforated PVC pipe fully enveloped in pea gravel or washed rock and be placed at the footing subgrade elevation around the outside of the perimeter foundation. Site grades should be planned to provide a positive surface drainage away from the buildings and to avoid ponding. Roof and surface runoff should not discharge into the footing drain system. Instead, a separate tight line drain network should be installed to direct runoff away from the complete buildings. 4.4 Preload/Surcharge Considerations The relic settling pond sediments underlying the eastern 150 to 200 feet of the building pad would tend to consolidate under the loads imposed by site filling and the structure, and without preloading the foundation could experience unacceptable settlements. In order to reduce post - construction settlements to an estimated range of 1 inches or less, we recommend preloading the eastern 225 feet (mezzanine portion) of the maintenance building pad with a temporary fill. Within the bus wash and fueling building pads, and the eastern portion of the paved areas, as shown on Preload and Parking Plan, Figure 3, some short-term settlement is possible due to site filling above deep settling pond sediments. Within these areas, we recommend that site filling be completed to the top of the parking lot slab at least 45 days prior to paving or foundation construction. Following the 45-day period, we estimate that tong -term post -construction settlements will be 1 inch or less. This 45-day period could be reduced based on survey results from the settlement markers described below. In order to reduce post -construction settlements to reasonable magnitudes, we recommend a preload intensity of about 700 pounds per square foot (psf). Assuming a unit weight for a A