7100 HARDESON RD Geotech Report 2025-03-06

Geotechnical Engineering Report lierracon Merrill Creek Operations Base Expansion • Everett, Washington December 14, 2020 • Terracon Project No. 81205012 Ge R p i ESaw-cut control joints should be placed in the slab to help control the location and extent of cracking. For additional recommendations refer to the ACI Design Manual. Joints or cracks should ' be sealed with a water-proof, non-extruding compressible compound specifically recommended for heavy duty concrete pavement and wet environments. Where floor slabs are tied to perimeter walls or turn-down slabs to meet structural or other construction objectives, our experience indicates differential movement between the walls and slabs will likely be observed in adjacent slab expansion joints or floor slab cracks beyond the length of the structural dowels. The Structural Engineer should account for potential differential settlement through use of sufficient control joints, appropriate reinforcing or other means. Particular care should be given to detailing of inspection pit walls where they join the floor slab. Floor Slab Construction Considerations Finished subgrade should be protected from traffic, rutting, or other disturbance and maintained in a relatively moist condition until floor slabs are constructed. If the subgrade should become damaged or desiccated prior to construction of floor slabs, the affected material should be removed and structural fill should be added to replace the resulting excavation. Final conditioning of the finished subgrade should be performed immediately prior to placement of the floor slab support course. The Geotechnical Engineer should observe and document the condition of the floor slab subgrades immediately prior to placement of the floor slab support course, reinforcing steel, and concrete. Attention should be paid to high traffic areas that were rutted and disturbed earlier, and to areas where backfilled trenches are located. L EARTH PRES SURES SURES S One or more inspection pits may be included in coach maintenance bays. We expect the depth of these pits may be up to 6 feet below the finish floor slab elevation. Below-grade vaults — such as oil-water separators or other below-grade stormwater handling structures, and below-grade equipment vaults or plenums associated with the paint booth — may be included with site design. The lateral earth pressure discussion and parameters below assume that these structures will be relatively rigid, and that wall movements/rotations required to achieve an "active" soil pressure condition are not acceptable for this project. Below grade structures such as coach inspection pits, stormwater vaults, equipment vaults and plenums, and similar structures are expected to be installed using open-cut techniques and backfilled with Structural Fill. However, this expectation assumes that these below-grade structures will be situated a suitable distance from shallow foundations to avoid additional loading from the foundation and to avoid impacts to the foundation. Lesser separation distances should be reviewed by the Geotechnical Engineer. For design purposes, a below-grade structure that Responsive • Resourceful ■ Reliable 15