2802 HOYT AVE EVERETT ELKS Geotech Report 2018-01-02 MF Import

GeotechnicahEngineering Evaluation Everett Elks Club November 2, 2006 NGA File No. 751 106 Page 9 Soldier Wall Design: The shoring wall should be designed by an experienced structural engineer licensed in the State of Washington. In many cases, shoring contractors have qualified structural engineers on board, or have a working relationship with qualified wall designers. In any case, the wall designer should be provided a copy of our report, and we should be retained to review the shoring wall design prior to construction. If the shoring wall is allowed to yield at the top at least one thousandth of the height of the above ground portion of the wall, the wall should be designed for an active loading condition. If the wall is restrained from yielding by external bracing, tiebacks, or wall stiffness, the wall should be designed for an at -rest loading condition. Active pressure acting on the piles and lagging for design of the soldier piles should be calculated based on a triangular pressure distribution equivalent to that exerted by a fluid with a density of 40 pounds per cubic foot (pcf). If at -rest conditions prevail, the wall should be designed to resist loads resulting from a triangular pressure distribution equivalent to that exerted by a fluid with a density of 65 pcf. These values are based oil an assumed level wall backslope, and assume no surcharge loads behind the wall. Additional surcharge loads on the wall should be considered from adjacent foundation, slab, and pavement loads. We are available to provide consultation regarding additional surcharge loads on the shoring wall after the final wall location is determined. The above loads should be applied on the full center-!o-center pile spacing above the base of the cut These loads could be resisted by passive resistance acting on the below - grade portion of the piles, an L'or by tie -backs extending into the native soils behind the shoring wall. The passive resistance could be calculated based on a 250 pcf equivalent fluid density acting on two effective pile diameters below the base of the cut. This value incorporates a factor of safety of 2. The below -grade portion of the wall should not be shorter than 1.2 to 1.5 times the wall stick-up height. Shoring Wall Installation: The shoring wall should be installed by a shoring contractor experienced with this type of system. Although, we anticipate that an open -hole drilling method will be adequate for installing the soldier piles, the selected shoring contractor should be capable of casing the holes should sloughing conditions and/or water seepage be encountered. It nught be prudent to perform a few "tes'." (toles to confirm installation conditions prior to finalizing work plans. Any sloughing or water that may collect in the drilled holes should be removed prior to pouring grout. Grout should be readily available on NELSON GEOTEcHNICAL ASSOCIATES,