711 112TH ST SE 7 ELEVEN Geotech Report 2018-01-02 MF Import

( Subsurjacc rxplorarim� m�d ProposeA 7-Eleven Propertv Geatechnica! Engineering Repon Fverert, Washin¢mn Desipn Recnmmendatians TnUle 1 Allow�ubie Picr Loads Embedmcnt Approximate Maximum Vertical Cnpacit}� Diametcr (estimated total len th) Len h(bnsed on EP-4) (tons) 18 inches 3 feet 15 feet 6 18 inches 5 feet 17 feet ]0 18 inches 7 feet 19 feet 14 IS inches 9 feet 21 feet 18 13 inches 11 feet 23 feet 24 Lateral Pier Capariry Although the majority of lateral resistance to wind and seismic loading will be generated by the grade beams, the piers will provide an additional capaciry of 2A rons (applied at the pier top) per pier. Piers within ]0 feet of another picr along the direction of force should be considered to be in the zone of influence and the lateral capacity of only one of these piers should be used in design. Allowable design loads may be increased by one-third for short-term wind or seismic loa�ling. Anti�ipated settlement o� pier-supported structures should be less than I inch. 9.4 Small-Diameter Pipe Piles An alternativc method for providing deeper foundation support for the Phase 11 office building would be to use small-diameter pipe piles. Pipe piles rypically are 3 or 4 inches in diameter and are driven to an acceptcc� refusal crireria using hydraulic or oscillatory methods. If pipe piles are used for foun�ation support of thc office building, we recommend nominal 4-inch- diameter, Schedule 80 pipe be used. The pipe should be driven to refusal and penetrate thc existing fill sail layers. For 4-inch-diameter pipe, driven with an 850 foot-pound hammer, refusal is typically defined as 14 to 16 seconds per inch penetracion. Four-inch-diameter pipe driven to refusal will be capable of providing a vertical capaciry of 5 tons each. Allowable design loads may be increased by one-third for short-term wind or seismic loading. Anticipated settlement of pipe pile-supported strucmres should be Iess than 1 inch. While providing suitable vertical capaciry, the driven pipe piles provide litde resistance against lateral forccs. The resistance ro lateral forces can be improved by installation of battered piles and by the design of the grade beam system. The number and spacing bettveen piles and Ihe design uf gradc bcams should be performed by a structural engineer. ,NnrcH /9, 2(X)l .�SSOCL�TED E�RTN SCIEh'C£S sRx„��.n�e�norv-v.n�ur„��r�n-�cn� Poge 11 I�