3003 W CASINO RD BLDG 45-06 Geotech Report 2025-03-03

Geotechnical Engineering Report lierracon I Proposed Flight Line Steam Line Project Boeing Everett Facility • Everett, Washington January 17, 2012 • Terracon Project No.: 81115085 Cobbles or boulder sized materials may be exposed in footing and floor slab excavations. Such conditions could create point loads on the bottom of footings and mat foundations, increasing ' the potential for differential foundation movement or cracking. If such conditions are encountered in excavations, the cobbles and/or boulders should be removed and the resulting 111 excavation backfilled with engineered fill meeting the requirements of Section 9-03.17, Foundation Material Class A, as presented in the WSDOT Standard Specifications for Road, Bridge, and Municipal Construction. We recommend that the utilidor foundation areas be surfaced with at least 6 inches of compacted engineered fill meeting the requirements of Section 9-03.17, Foundation Material ' Class A, as presented in the WSDOT Standard Specifications for Road, Bridge, and Municipal Construction. The foundation material should be placed directly on dense to very dense glacial till soils. The purpose of the foundation material is to provide 1) protection for the moisture , sensitive glacial till subgrade during construction, 2) a leveling surface for precast utilidor components, and 3) more uniform support conditions between precast and cast-in-place components. The foundation material should be compacted to a firm and non-yielding condition and to at least 95 percent of the modified Proctor maximum dry density as determined by the ASTM:D-1557 test procedure. I 4.2.7 Engineered Fill Material Recommendations The utilidor is located within a paved industrial area. As such, all fill material placed for this 111 project should be placed in accordance with the recommendations herein for engineered fill. Prior to placement, the surfaces to receive engineered fill should be prepared as previously described. All engineered fill should be free of organic material, debris, or other deleterious material. Individual particle size should be less than 3 inches in maximum dimension. The suitability of soils for use as engineered fill depends primarily on the gradation and moisture , content of the soil when it is placed. As the amount of fines (that soil fraction passing the U.S. No. 200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult, or impossible, to achieve. Generally, soils containing more than about 5 percent fines by weight (based on that soil fraction passing the U.S. No. 4 sieve) cannot be compacted to a firm, non-yielding condition when the moisture I content is more than a few percent from optimum. The optimum moisture content is that which yields the greatest soil density under a given compactive effort. Recommendations for engineered fill are presented in the following sections. The use of other fill types should be reviewed and approved by the engineer. Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture content and densities throughout the fill. Fill lifts should not exceed 8 inches in loose thickness. I I Responsive • Resourceful • Reliable 8 I