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1 <br /> amec <br /> foster <br /> wheeler <br /> EXECUTIVE SUMMARY <br /> This summary of project geotechnical engineering considerations is presented for introductory <br /> purposes and should be used only in conjunction with the full text of this report. <br /> Project Description: The project site is currently an active school campus. Construction plans call for <br /> demolishing both existing school buildings for construction of a new two-story school building. The <br /> existing school gymnasium will not be demolished but has been integrated into the new school <br /> building configuration. The planned site layout shows the reconfigured new school building, parking <br /> and bus lanes west of the school building, and associated infrastructure, such as walkways and <br /> utilities, reconfigured around the building perimeter. The athletic field north of the school building will <br /> be redeveloped for a football field in the eastern half with a baseball field and running track in the <br /> western half. Only minor changes are planned for the parking lot and tennis courts south of the school <br /> campus across 26th Street. The parking lot will remain as is. The tennis court surface will be striped <br /> and converted into additional parking stalls. <br /> Exploratory Methods: We explored subsurface conditions around the school buildings and athletic <br /> field by drilling six borings (B-1 thorough B-6) on September 6, 2016, at strategic locations across the <br /> redevelopment area to depths of 15 to 21.5 feet below the ground surface (bgs). <br /> Soil Conditions: The subsurface soil conditions encountered were relatively uniform across the site. <br /> Borings B-1 and B-2 in Bagshaw Field encountered 1 foot of sand over 2.5 to 3.5 feet of loose fill over <br /> 10.5 to 12.5 feet of soft to very stiff fine sandy silt (Recessional Lacustrine) underlain by dense silty <br /> sand (Advance Outwash) to the full depth of the borings. Boring B-2 encountered 1 foot of relic topsoil <br /> between the fill and native silts. Borings B-3 through B-5 were advanced around the perimeter of the <br /> existing school buildings and encountered 1 to 3 feet of fill over 10 to 15 feet of stiff to very stiff fine <br /> sandy silt (Recessional Lacustrine) that was underlain by dense to very dense silty sand (Advance <br /> Outwash) to the borings' extent. Boring B-6, advanced in the north edge of the parking lot south of <br /> 26th Street, encountered 5.5 feet of very loose to medium dense fill over stiff fine sandy silt <br /> (Recessional Lacustrine). <br /> Groundwater Conditions: No groundwater was encountered in any of the explorations. However, at <br /> the drainage sand—soil subgrade contact horizon in Bagshaw Field, water was encountered and <br /> appeared to be caused by the athletic field irrigation system. <br /> Foundations: We recommend constructing gravel bearing pads to support spread footings. The <br /> bearing pads should be 1 foot thick and extend 1 foot beyond the edges of the footing. Also, a <br /> Amec Foster Wheeler <br /> Project No.6-917-18116-0 <br /> \\Sea-fs1\WordProc\ Projects\18000s\18116 Everett School District\Geotech Report\Revised\2017_10-19_Everett Middle School Geotech_Sx.docx <br />