HomeMy WebLinkAboutObservation of Excavation 8.11.2022lClImilmiff*'*"
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phone: (970) 945-79ttB
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August 11,2022
Shane Smith
2995 County Road 311
Silt, Colorado 81657
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Project No.22-7-328
Subject:Observation of Excavation, Proposed Shop, 2995 County Road 311, Garfield
County, Colorado
Shane:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on August 4,2022 to evaluate the soils exposed for foundation support. The findings
of our observations and recommendations for the foundation design are presented in this report'
We previously conducted a subsoil study for design of the residence foundations at the site and
presented our findings in a report dated August22,2A16, Project No. 16-7-308. The current
observation was conducted in accordance with our agreement for professional engineering
services to you dated April 28,2022.
The shop will be a 1 or 2-story structure with slab-on-grade floor. Spread footings placed on the
natural soils were designed for the foundation support.
At the time of our visit to the site, the foundation trench excavations had been cut in one level
about 5 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of silty clay and sand with organics. We understand that small cobble rock
was placed at the cut depth to improve the ground conditions for construction purposes due to the
soft wet soils. The results of laboratory testing performed on a sample of the natural soils are
presented in Table 1. No free water was encountered in the excavation and the soils were very
moist.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site and can be used for support of spread footings designed for the recommended
allowable bearing pressure of 1,000 psf with a settlement risk. Loose disturbed soils and mud
should be removed in the footing areas prior to concrete placement. Other recommendations
presented in our previous report which are applicable shouid also be observed.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and the previous limited subsurface exploration at the site'
Variations in the subsurface conditions below the excavation could increase the risk of
foundation movement. trVe should be advised of any variations encountered in the excavation
conditions for possible changes to recommendations contained in this letter. Our services do not
Shane Smith
August 11,2022
Page2
include determining the presence, prevention or possibility of mold or other biological
contaminants (MOBC) developing in the frrture. If the client is concemed about MOBC, then a
professional in this special field ofpractice should be consulted.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associateso Inc.
Steven L. Pawlak,
SLP/kac
Attachment:Table I Test Results
152?,.
Kumar & Associates, lnc. o'Project No. 22-7-328
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-7 TABLE I
SUMMARY OF LABORATORY TEST RESULTS
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LIOUþ LIMT
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PLASTIC
¡itoEx
IPSFI
ur{coI{FTNED
cotPREssrvE
STREI,IGTH
sotl oR
BEDROCKWPE
GRAVEL
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SAND
(%)
PERCÊì]T
PASSING ìIO.
200 stEvE
BOTTOM OF Þ(CAVATION
NATURAL
ITIOISTURE
coNTEt{f
NATURAL
ORY
DEt{StfY
lælt
Very Silty Clayey SandSouth Side 19.7 108