1875.01_DFR 3_11.07.17.pdfZipper Geo Associates
Daily Field Report
ZGA Project
1875.01
Daily Field
3 Page: 1 of 2
No.:
Report No.:
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Project:
Stormwater Detention Pipe
Location:
622 Bell Street —Edmonds, WA
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Installation Evaluation
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Client: ......... ..........
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Johnny Vong
Contractor:
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Al Asphalt
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ZGA Field Rep:
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B. Fowler
Permit No.:
................................................................................................................................................................................
6354052
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Date:
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11/7/2017
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Arr./Dep. Time:
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9:00 am / 11:00 am, 1:30pm / 2:00pm
Weather
Overcast, 50s
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Equipment
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Plate compactor, skid -steer loader,
Used:
HMA paver
We arrived on site at the request of the client Johnny Vong. The purpose of our site visit was to evaluate utility trench
backfill in the City of Edmonds right-of-way.
Utility trench backfill
Upon arrival, we observed that the contractor had installed and backfilled above a storm drain pipe that extended laterally
across Bell Street from CB # 4 and runs parallel next to the sidewalk in front of the residence. ZGA was not onsite during
installation of the pipe and did not observe backfill compaction. As such, ZGA can only evaluate the compaction of upper
6 to 12 inches of the trench backfill. Project superintendent Johnny Vong indicated that the City of Edmonds requires
compaction testing of the trench backfill that extended into Bell Street. The paving contractor, Al Asphalt was on site to
remove the existing cold patch, prepare the subgrade, and pave the utility trench lines. The contractor saw cut the cold
patched areas and roughly 1% feet laterally of the existing roadway around the cold patch areas. After removing the cold
patch, the contractor re-compacted/smoothed out the trench backfill with a plate compactor in preparation of paving.
We observed that the earthwork contractor had backfilled above the utilities with pit run sand and gravel. We completed
two in -field nuclear density tests at pavement subgrade elevation, one each in the westbound and eastbound lanes. All
test results met or exceeded 95 percent compaction. Test results are shown in Table 1 below.
Mr. Vong asked that we visit the site later in the day to observe subgrade preparation of the section of trench backfill that
extended parallel to Bell Street next to the sidewalk. Initial hand probing of that section of trench line penetrated 6 to 8
inches. Fill generally consisted of a mixture of pit run sand and gravel, 5/8-inch minus crushed rock, and recycled concrete
fragments, as such conventional nuclear density testing was not feasible due to the coarse nature of the material. We
recommended that the trench section be compacted to a firm and unyielding state prior to paving to reduce the risk of
settlement. The paving contractor indicated that the upper 4 inches of loose material would be removed and the
underlying subgrade re -compacted. When we arrived on site in the afternoon, we observed that the contractor had
removed the loose fill and compacted the subgrade with a plate compactor. Subsequent hand probing penetrated
minimally indicting that the fill had been adequately compacted for pavement subgrade, in our opinion.
Reviewed by: ljitw
This field report presents the results of our on -site testing as well as the observations and opinions of the field representative regarding the contractor's activities.
The contractor is responsible to complete the project in accordance with the approved plans and specifications regardless of our presence on site and our
observations and test results. Our services do not include supervision or direction of the contractor's work of that of its subcontractors or responsibility for job site
Zipper Geo Associates
Daily Field Report
Daily Field Report
ZGA Project No.: 1875.01 3 Page: 2 of 2
No..
..................................................................................................................................................................................................................................................................................................
Stormwater Detention Pipe
Project: Date: 11-7-17
Installation Evaluation
Table 1. Summary of Field Density Test Results
Test
Test
Test
General
Approx.
Feet
Mat'I
Field
%
%
Pass/Fail
Elev.
No.
Date
Method
Location
to
Type
Dry
Field
Comp.
(ft)
Grade
Density
Moist.
Field
(pcf)
DT-1
11/07
N
CB # 4 trench
N/A
0
1
129
4
95
P
backfill in City
of Edmonds
right-of-way
(WB lane)
DT-2
11/07
N
CB # 4 trench
N/A
0
1
131
4
96
P
backfill in City
of Edmonds
right-of-way
(EB lane)
Percent Compaction Based on: Specification:
® Modified Proctor, ASTM D 1557 ® 95% ❑ 90%
LEGEND
DT = Density Test
RT = Retest
TEST METHOD
N = Nuclear (ASTM D 292)
Optimum
Material
Reference
Material
Max. Dry
Moisture
Type
Sample #
Description
Density (pcf)
(%)
Import Fill (pit run
1
NA
136
5
sand and gravel)
*Typical value based on material composition.
19023 36t" Avenue W., Suite D, Lynnwood, WA 98036 P (425) 582-9928 F (425) 582-9930