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Geotechnical Engineering Report lrerracon <br /> Proposed Flight Line Steam Line Project <br /> Boeing Everett Facility• Everett, Washington <br /> January 17, 2012 • Terracon Project No.: 81115085 <br /> 1 H:2V slope extending down and away from the edges of a surface surcharge, the change in <br /> pressure (Aq) beneath the surcharge may be calculated as Aq=V/(B+Z)(L+Z), were V is the total <br /> vertical surcharge load, B and L are the horizontal dimensions of the surcharge load area at the <br /> ground surface, and Z is the depth below the ground surface. It should be understood that this is <br /> a relatively simple calculation method that does not include the load distribution effect of the <br /> rigid concrete pavement section. Terracon is available to assist in more detailed vertical load <br /> distribution analyses, at your request. <br /> 4.7 Existing Foundation Protection <br /> Preliminary plans indicate that the northern portion of the utilidor will be constructed near <br /> existing structures. In particular, it appears that the north end of the utilidor will be located within <br /> a few feet of the east side of Building 40-21. Creating stable, temporary open cut excavations <br /> near existing foundations is typically the most cost effective means of maintaining adequate <br /> support for existing foundation elements during the construction of new facilities with deeper <br /> foundations. In order to maintain adequate foundation support for existing structures, we <br /> recommend that temporary open cut excavations made near the existing foundations be set <br /> back from the edge of existing foundation elements. Based on the soil types encountered in our <br /> explorations, we recommend that all temporary open cuts made adjacent to existing shallow <br /> foundation systems include of a level bench extending out from the edge of the existing footing <br /> a minimum distance of 3 feet. The elevation of the level bench should be greater than or equal , <br /> to the base elevation of the existing footing. Soils beyond the 3-foot minimum setback distance <br /> may be cut at a maximum temporary slope angle of 45 degrees (1H:1V). If the foundation <br /> subgrade elevation for existing structures and the proposed utilidor location and foundation <br /> depth do not allow enough room for the recommended temporary open cut configuration, we <br /> recommend that temporary support for existing foundations be provided by structural means. <br /> Preliminary plans indicate that the Building 40-21 column foundations located nearest to the <br /> planned utilidor have a bottom of footing elevation of about 540 feet. It is not clear based on the <br /> currently available information if shallow spread wall footings connect the Building 40-21 column <br /> foundations. We anticipate that the Building 40-21 column foundations carry a significant load. <br /> Based on preliminary plans, it appears that the bottom of the utilidor near Building 40-21 will <br /> have a foundation elevation of about 532 feet. Based on the current location and depth of the <br /> utilidor, temporary open cuts near the Building 40-21 column foundations do not appear feasible <br /> from a geotechnical perspective. Structural support for the existing foundations could be <br /> provided by soldier pile underpinning. Terracon is available to provide underpinning <br /> recommendations, at your request. Existing foundation location, depths, and loads will be <br /> required to develop geotechnical soldier pile underpinning recommendations. A structural <br /> engineer will likely be required to design the soldier pile to foundation connection. <br /> Responsive • Resourceful • Reliable 18 <br /> 1 <br />