10200 19TH AVE SE COSTCO FUEL STATION 2016-01-01 MF Import

GEOTECHNICAL ENGINEERING STUDY Costco Wholesale c/o Barghausen Consultinq Engineers E-8556 January 13, 1999 Page 6 For foundations bearing on at least two feet of structural fill, an allowable soil bearing capacity of two thousand five hundred 12,500) psf can be used. Footings bearing on the competent native soils underlying the fill can be designed using ��n allowable soil be�ring capacity of five thousand (5,000) psf. Continuous and individual �pread footings should have minimum widths of eighteen (18) and twenty-four (24) inches, respectively. Loading of this magnitude would be provided with theoretical factor-of-safety in excess of three against actual shear failure. A one-third increase in r.he above allowable soil bearing capacities can be assumed for short-term wind and seismic loading conditions. Exterior foundation elements should be placed a minimum depth of eighteen (18) inches below final exteriar grade. Interior spread foundations can be placed at a minimum depth of twelve (12) inches below the top of slab, except in unheated areas, where interior foundation elements should be founded at a minimum depth of eighteen (18) inches. Assuming foundation support for the proposed structures is in accordance with the recommendations contained in this reoort, we expect total settlements of approximately one inch and differential settlemeni of approximately one-half inch. Most of the anticipated settlements should occur during construction as dead loads are applied. Lateral loads can be resisted by friction betweE:n the base of the foundation and the s�pporting soil, and by passive soil pressure actinq on the face of the buried portion of the foundation. The foundation excavations must be backfilled with structural fill Yo establish adequate passive resistance around the foundation elements. Resistance to Iateral loads from passive earth pressures can be calculated using an �quivalent fluid pressure of three hundred fifty (350) pounds per cubic foot {pcfl. For frictional capacity, a coefficient of 0.40 may be used for foundations elements bearing on competent native soils or structural fill. These lateral resistance values are allowable values, a factor-of-safety of 1 .5 has been included. Footing excavations should be observed by a representative of ECI, prior to placing forms or rebar, to verify that conditions are as anticipated in this report. Compaction testing of structural fill in foundation areas should be periodically performed by ECI. Eanh Consultnnis, hc. I�