8215 BROADWAY 2016-01-01 MF Import

ADaPT Ee¢ineerin¢, Ioc. Passive Pressure Method: Thc passive pressurc approach is conscrvative by neglecting the redistribution oC vertical stresses and shear forccs that devclop near the bottom of the pier and contribute to resisting lateral loads. We rccommend using the allowablc passivc carth pressure (expresscd as equivalcnt fluid unit weights) listed in Table 3. The allowable passive pressurc for soils below the maximum depth of the test boring may bc assumed to be as that shown for the lowest depth i��crement below. Table 3 Allowable Passive Pressures Depth (fcet) Allowable Passive Pressure (pc� p.2 0 2-12 250 12-28.5 350 The allowable passive earth pressure prescnted in 1'able 3 may be assumed to be acting over an area measuring 2 pier diameters in width by 8 pier diametcrs in depth, neglccting the uppermost 2 fcet of embcdment bclow the ground surface. According to the NAVPAC Design Manual 7.02 (1986), a lateral dc(lcction equal to about 0.01 timcs thc pier length would be required to mobilize the allowable passive pressure presented abovc. Highcr detlections would mobilize highcr passive pressures. When devcloping thc a!lowaLle passive pressure listed in Table 3, we have incoiporatcd a safety factor of at least 1.5, which is commonly applied to transient or seismic loading conditions. nlodulus of Suberade Reaction Method: Using this method, the pier is designed to resist latcral loads bascd on acceptable lateral detlection limits. For sandy soils, the cocfticient of horizontal subgrade reaction (ki,) is considercd tQ be d'rrccdy praportional to thc depth along thc pier. The formula to determine kh is kh = ni,x, where x is the depth below thc ground surface in inches. We recommend using thc value for the constant of horizontal sub��ade reaction (nh) for the various soil typcs presented in Table 4 bclow. The constant of horizontal subgrade rcar�ion may be assumed lo be equal to 70b pci for soils beyond the boring penctration depth. Table 4 Constant of liorizontal Subgradc Rcaclion (nh) Dcpth (feet) nh (p��) 0-2 0 2-12 20 12-28.5 70 Construction Considcrations: At this sitc, the near surface soils consis[ of loose to medium dense nativc fill materials b�rades to very dense till soils below 12-fcet at Qic location of boring B-I. Hard drilling conditions were en;ountered betwcen about 12 and 28.Sdeet bgs during drilling. The ground surface in the Icase area exhibits conerete rubble and wood debris. In addition, cobbles and boulders (ertatics) are VoiccStrcam Wireless H� �1 �s� �� ADaPT Pmjcct No. WA00-0074 P°LK �