2824 GRAND AVE NAUTICA CONDOMINIUMS 2018-01-02 MF Import

GEOTECHNICAL ENGINEERING STUDY Cascasia Pacific Properties, Ltd. July 15, 1999 E-8602 Page 12 For resistance to uplift, not including the weight of the pile, an allowable uplift capacity of twenty (20) tons can be used. An allowable lateral load capacity was calculated for eighteen ( 18) inch diameter augercast piles, based on a horizontal modulus of subgrade reaction of sixty (60) pounds per cubic inch (pci) and an allowable deflection of one-half inch. Based on the above assumptions, an allowable lateral load capacity of fifteen (15) tons can be used for free head conditions, and an allowable lateral load capacity of thirty-five (35) tons can be used for fully fixed head conditions. The allowable lateral load capacities can be evaluated for other values of allowable deflection, if requested. The subgrade reaction approach (Besse and Matlock, 1956) was considered as part of the lateral load analyses. If requested, interaction diagrams for determining moment/deflection characteristics of the pile can be provided. We estimate differential settlements using a pile foundation will be less than one-half inch. Seismic Design Considerations The Puget Sound region is classified as Zone 3 by the Uniform Building Code (UBC). The largest earthquakes in the Puget Sound region have been subcrustal (intraplate) events, ranging in depth from fifty (50) to seventy (70) kilometers. Such deep events have exhibited no surface faulting. Weaver and Shedlock (1989) researched the probable or known source areas for the crustal, intraplate, and subduction zone earthquakes in the Washington and Oregon area. Crustal and intraplate earthquakes are the only events in Washington and Oregon in which there is a historical record. Shallow crustal earthquakes occur within the North American Plate, and typically do not exceed focal depths of approximately 20 kilometers. Intraplate earthquakes occur in the subducting Juan de Fuca plate, and typically occur below depths of 40 kilometers. The subduction .-one earthquake, in which there is no historical record in the Washington and Oregon area, would have its source along the interface between the North American Plate and the subducting Juan de Fuca Plate. Magnitude 8+ e; •thy i;;kes are thought to be possible along this interface, and would occur at depths of a, . .iroately 50 to 60 kilometers (Weaver and Shedlock, 1989)• The UBC Earthquake regulations have established a series of soil profile types that are used as a basis for seismic design of strictures. Based on the encountered soil conditions, it. is our opinion that soil type So from Table 16-J of the 1997 UBC should be useJ for design. Earth con..H.M., Inc.