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American Property Development ES-0599.06 <br /> June 9, 2016 Page 9 <br /> Revised October 16, 2017 <br /> • Apparent Earth Pressure 19H (psf), where "H" is the height of excavation <br /> • Slope Surcharge Hs/2 (ft.), where "Hs" is the height of slope* <br /> • Traffic Surcharge (where applicable) 70 psf, rectangular distribution <br /> • Preliminary Building Surcharge 125 psf(rectangular distribution)** <br /> *Add `Hs" to excavation height in calculating apparent earth pressure value. See Plate 4 for distribution of <br /> apparent earth pressure <br /> **Building surcharge values should be reevaluated based on further assessment of adjacent building foundation <br /> levels,proximity, and loading <br /> Soldier Piles <br /> Soldier pile installation should be observed by the geotechnical engineer to verify pile depths <br /> and soil conditions. If sloughing of the soldier pile excavation occurs, the contractor should be <br /> prepared to case soldier pile excavations, as necessary. Where groundwater seepage is <br /> encountered in excavations, localized sloughing should be expected. <br /> Timber Lagging <br /> Lagging should be installed in maximum four-foot lifts as the excavation is advanced. Lifts of <br /> up to six feet maximum may be acceptable for short periods, provided the lagging is installed <br /> immediately. The geotechnical engineer should observe the shoring excavation to assess the <br /> stability of the cut. The lagging should be backfilled as the excavation is advanced to minimize <br /> voids between the lagging and cut face, and to reduce the potential for ground subsidence <br /> behind the shoring wall. Where sloughing of the excavation results in the development of a <br /> large void, injecting lean mix into the void area should be considered. <br /> Due to anticipated soil arching between soldier piles, the timber lagging can be designed with a <br /> reduced pressure equal to thirty five percent of the design lateral earth pressure. <br /> Tieback Anchors <br /> Tiebacks should be located as high on the wall as possible and should be designed based on <br /> the following parameters: <br /> • Allowable Anchor Friction 1,900 psf <br /> • Declination Angle 15 to 20 degrees (from horizontal) <br /> • Soldier Pile End Bearing 18,000 psf <br /> • No Load Zone See Plate 5 of this study <br /> Earth Solutions NW,LLC <br />