4920 EVERGREEN WAY STAPLES 2020-02-07

Terracon Consultants, Inc. Geotechnical Engineers and Environmental Consultants lierracon 21905 64th Ave. W., Ste 100, Mountlake Terrace,WA 98043 0: (425)771-3304 F: (425) 771-3549 Report No.: 001 Date: September 19, 2019 1 of 4 Project: Staples Rockery Replacement Terracon Job No: 81175122 Client: Hilbers, Inc. Contractor: REV Drilling, Inc. Terracon Field Rep.: T. Benson Location: 4920 Evergreen Way Everett,WA Time Onsite: 0700 to 1545 Permit No.: W1712-001 Weather: Partly cloudy, high 50s Equipment: Refer to text Equipment Onsite GEAX DTC 80 (hydraulic rotary drill) REV Drilling, Inc. TB 285 (mini-excavator) REV Drilling, Inc. GTH-844 (forklift) REV Drilling, Inc. Linkbelt RTC-8065 (crane) REV Drilling, Inc. A Terracon representative was onsite at the request of the general contractor, Hilbers, Inc. (Hilbers) to observe soldier pile installation by the retaining wall subcontractor, REV Drilling, Inc. (REV). Soldier Pile Installation The Terracon representative observed and documented the installation of soldier piles by REV. A total of 2 soldier piles - P-14 and P-16 —were installed, leveled, and backfilled with structural concrete and lean mix per the contract documents. Soils encountered were generally consistent with the soil units described in the geotechnical engineering report. Prior to installation of the soldier piles, a Terracon representative observed the piles prior to installation. This discrepancy was evaluate by Terracon and deemed not withstanding for this piles. The piles arrived with a protective coating of corrosion inhibiting compound. The bottom 7 to 8 feet of the piles were not protective coated as this unprotected length will be placed in structural concrete, and is considered acceptable. Work began at P-14 and progressed to the south to P-16. Drilling was performed using a 30-inch diameter auger without the use of casing. The drilled shaft remained relatively stable throughout soldier pile installation with little to no caving observed. Piles were placed in the shaft via crane and leveled using hand levels, an alignment stringer, wood lagging, and clamps to suspend the soldier piles above the base of the shaft. No water was observed in the bottom of the shafts following soldier pile leveling and before placement of structural concrete. Structural concrete was delivered by Smokey Point Concrete(mix design PG60P)and Concrete was gravity fed directly to the shaft from the mix truck.The concrete was placed to an approximate elevation of 305 feet within each shaft, which is a depth of about 11 feet from the base of the shaft and covers the unprotected length of pile. The shaft is then filled with lean mix concrete from the top of the structural concrete to ground surface using the same process described for structural concrete. Installation details of each pile are presented on the pile installation forms attached to this report. During drilling of the soldier pile shafts and installation of the soldier piles, the Terracon representative periodically obserbved the condition of the rockery. No significant changes to the condition of the rockery were observed during soldier pile installation. A Terracon representative will return to the site tomorrow, 9/20/19, to continue observation of soldier pile installation. To the best of our knowledge, work was completed consistent with the contract documents. .ekikREVIEWED BY: Zachary L. Koehn,P.E. )`' This report presents opinions formed as a result of our observations of the contractors activities relating to geotechnical engineering. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of the Terracon field representative. The presence of our.. field representative will be for the purpose of providing observation and field testing services. Our work does not include supervision or direction of the actual work of the contractor,its employees,or agents. Neither the presence of the Terracon field representative nor the observation and testing by Terracon shall excuse the contractor in any way for defects discovered in its work. Terracon will not be responsible for job or site safety on this project.