2000 HEWITT AVE EVERETT EVENT CENTER 2018-01-01 MF Import

. . � � �: conshuction slope will extend hom Elevation 80 w the plane of the vertical shoring wall. As shown on the Elevation of the Design Drawings, the theoretical intersection of the constructioe slope with the shoring wall is genecally at or above Elevation 106 feet. Because of the poorer quality soils at shallow depth,as noted below, and the relatively steep construction slope in &ont of the wall, the shoring wall has bern designed assuming an effective base of excavation at Elevation 104 feet. 2. SUBSURFACE CONDITIONS As pnsented in the geotechnical investigation rcport, the site has been investigated by a series of exploratory boreholes and associated soil classification usring. In thc viciniry of the plenned shoring, these investigations have indicated that the subsurface conditions consist of sevml fcet of silty sand fill, ovalying medium dense sands to a depth of 12 to 14 feet and dense gtaci411y overridrn send and silty sand, with local silt la�ers. Perched groundwater was rncouncered during drilling but it is anticipated that drainage/deprcssurization of water in the vicinity of the wall will occur during excavation to depths in ezcess of 20 Cat below the base of the shoring. 3. DESIGN 3.1 Concept ' The retaining structure consists of solditt pi!cs in�talled along the Irngth of the wall section to be shored. The soldier piles will be embedded into the underlying glacial soils. The piles will each be supported by a single anchor. Cantilevered pi' s have not been used, evrn at the end of the wall where the height is limited,because of the low allewable passive toe support provided by the 1H:1V slope beneath the base of the shoring. Pile spacing is 8 feet and the wall lagging consists of treated wood. 3.2 Design Earth Pressures Earth pressures specified for design of the soldier pile shoring wall are: Equivalent uniform earth pressure 23H(H is wall height) Passive Earth Presswe Equivalent Fluid Density Above Elevation 90 feet 100 pcf Below Elevation 90 feet 240 pcf Lateral Live Load Surcharge Pressare 80 psf The equival�•nt uniform earth pressuro for the anchored wall is used to compute the actual total earth pressure load on the wall, and the appazent earth pressure distribution for assigning relarive loads between the anchor and the toe of the wall,and for calculating bending moments within the soldier pile, is indicated on the Drawings. Other design parameters used aze: Allowable Pile End Bearing 15 ksf Allowable Pile Skin Friction 1 ksf Allowable Anchor Pullout 3 kips/ft 3.3 Pile and Anchor Design Ground Support PLLC -(�