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Kirkland | Tacoma | Mount Vernon 425-827-7701| www.aesgeo.com
Date Mailed: Principal / PM: Bruce Guenzler, L.G., L.E.G.
This document is considered a DRAFT until signed or initialed by an AESI Principal or Project Manager
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FIELD REPORT
Date Project Name Project No. Report No.
11/16/2022 Renton Elementary School 16 20180398E003 069
Location Municipality AESI Project Manager AESI Field Rep
1075 Duvall Ave NE Renton Bruce Guenzler, L.E.G. Jackson Lundgren, G.I.T.
Permit No. Client/Owner Attn Requested By
B21004604 Renton School District No. 403 Ed Thomson Contractor
Engineer/Architect General Contractor Grading Contractor Weather
CPL / Hutteball + Oremus Cornerstone/Kyle Continental Dirt Contractors/ Jerry Jr. Sunny, 80’s
THE FOLLOWING WAS NOTED:
Associated Earth Sciences Inc. (AESI) was onsite at 7:00am at the request of the general contractor to observe excavation and
backfill within the southern parking lot and adjacent curb subgrades above the StormTech stormwater vault, as well as soil
conditions within light pole basin excavations along Duvall Avenue NE. While onsite we met with representatives from both
Cornerstone and Continental Dirt Contractors.
Excavation and Backfill
Upon arrival, AESI observed contractor perform a proof roll with a fully loaded front loader within the southern parking lot and
along adjacent curb subgrades. AESI observed areas of yielding and recommended excavating approximately 18 to 24-inches within
existing backfill material along the southern parking lot and adjacent curb subgrades, as well as above the top of the StormTech
stormwater vault (Fig 1).
AESI observed contractor excavate approximately 175 yards of saturated backfill material 18 to 24 inches below paving grade above
the top of the stormwater vault (Photo 1). AESI observed during excavation that backfill material being removed was moist to wet
and contained trace organics (wood) and cobbles. The excavated fill was reused on site soil, placed above a non woven filter fabric
separating the on site soils from washed rock backfill for storm water storage arches. The 6 to 12 inches of soil immediately above
the non woven fabric was saturated and very soft. At the AESI then observed contractor grade the excavation and place Tensar TX7
tri-axial geogrid along the approximately 100-foot by 30-foot excavated area (Photo 2). Contractor then backfilled excavation with
imported 2.5-inch minus crushed rock in approximately 8 to 12-inch lifts compacted with a large drum roller (photo 3). Contractor
relayed further excavation and backfill would continue 11/16/2022.
Light Pole Base Observations
AESI observed contractor had excavated 36 to 48-inch diameter boreholes to a depth of approximately 6 to 8 feet within native and
fill material along Duvall Avenue NE for light pole basins. AESI observed minor caving near the bottom 2 feet of the boreholes, as well as up to 4 feet of groundwater within the excavations. AESI recommended pumping water from the excavations before placement of
the rebar cages and concrete. Contractor relayed a vacuum truck would be utilized to remove groundwater and sediment sloughed
from the sides of the excavations during caving as needed. AESI recommended backfilling the approximately 2-foot deep trenches
for electrical conduit between basins with imported material. Contractor relayed light pole basins would be backfilled with imported
gravel borrow.
AESI will return for further observations and testing as requested by the client.
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Date Project Name Project No. Report No.
11/16/2022 Renton ES 16 20180398E003 069
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FIELD REPORT
Figure 1: Approximate area of over-excavation and backfill with imported 2.5-inch minus crushed rock shown in green, areas where further
excavation and backfill are recommend shown in red.
Photo 1: Excavation within saturated material along top of stormwater vault
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Date Project Name Project No. Report No.
11/16/2022 Renton ES 16 20180398E003 069
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FIELD REPORT
Photo 2: Placing Tensar TX7 tri-axial geogrid along graded surface on top of stormwater vault
Photo 3: Drum roller compacting 2.5-inch crushed rock imported backfill material within excavated area along top of stormwater vault