319 76TH PL SW 2016-01-01 MF Import

SERS Public Safeh, 9-1-1 Communication Tower ( 'SI Report No 704-05224-1 December 26, 2000 Page 11 Allowable lateral frictional resistance between the base of footings and the subgrade can be expressed as the applied vertical load multiplied by a coefficient of friction of 0.35 for the very dense native silty sand with gravel soil. In addition, lateral loads may be resisted by an passive earth pressure based on an equivalent fluid density of 300 pounds per cubic foot (pcf)on footings poured "neat' against in-situ soils or properly backfilled with granular structural fill, respectively. These recommended values include a factor of safety of approximately 1.5,which is appropriate due to the amount of movement required to develop full passive resistance. We estimate that foundations designed and constructed in accordance with the above recommendations will experience total settlements generally less than 1-inch with differential settlements between columns generally less than Yrinch. If footings are constructed during wet weather, it may be necessary to protect the foundation excavation bottoms from disturbance during construction activities. In this regard, we recommend that a 3 to 4-inch thickness of crushed rock be placed at the bottom of the footing excavations immediately after the excavation is completed. If footings are constructed during the drier summer months, this crushed rock layer should not be required. 5.5 Drainage Considerations The site should be graded such that surface water is directed away from strictures and off the site. Water should not be allowed to stand in any area where structures are to be constructed 5.6 Constr_:ction Monitoring It is recommended that PSI be retained to examine and identify soil exposures created during project excavations in order to verify that soil conditions are as anticipated. We further recommend that any structural fills be observed and tested by our representative in order to evaluate the thoroughness and uniformity of their compaction. If possible, samples of fill materials should be submitted to our laboratury for evaluation prior to placement of fills on site (at least one week in advance of starting fill operations). Costs for the recommended observations during construction are beyond the scope of this current consultation. Such future services would be at an additional charge 6.0 General Our conclusions and recommendations described in this report are subject to the following general conditions (,'11