HomeMy WebLinkAboutObservation of Excavation 09.29.18H.PVKUMAR 5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) 945-7988
Fax (970) 945-8454
Email: hpkglenwood@kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, Summit Counly, Colorado
September 29,2017
Amy and Chuck Perrin
38 Pinetree Place
Parachute, Colorado 81635
anUleeperriLG) gmai [, cq¡U
Project No. 17-7-460.01
Subject:Observation of Excavation, Proposed Residence, Lot 5, Bloek 1, The Preserve at
Battlement Creek, Battlement Mesa,0008 Meadow Creek Drive, Garfield
County, Colorado
Dear Mr. and Mrs. Perrin:
As requested, a representative of H-P/Kumar observed the excavation at the subject site on
September 14,2017 to evaluate the soils exposed for foundation support. The findings of our
observations and recommendations are presented in this report. We previously conducted a
subsoil study for design of foundations at the site and presented or"rr findings in a report dated
Jnly 11,2017, Project No. 17-7-460.
The proposed construction is similar to that discussed in our previous report. Spread footings
bearing on the natural soils designed for an allowable soil bearing pressure of 1,000 psf were
recommended for foundation support with some risk of settlement.
At the time of our site visit, the foundation excavation which was essentially complete had been
cut in one level from about Vzto 3 feet below the adjacent ground surface. The soils exposed in
the bottom of the excavation consisted of stiff, very sandy silt. The excavation subgrade had
been moistened and compacted. Results of swell-consolidation testing performed on sample of
the soils taken from the site, shown on Figure 1, indicate low compressibility under natural
moistu¡e and light loading conditions with a moderate collapse potential when wetted under a
constant light surcharge. The sample showed moderately high compressibility when loaded after
Geotechnical Engineering I Engineering Geology
Materials Testlng I Environmenial
Amy and Chuck Penin
September 29,20t7
Page2
wetting. The sample was likely disturbed due to the sampling process. No free water was
encountered in the excavation and the soils were slightly moist.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site and suitable for support of spread footings designed for the recommended allowable
bearing pressure of 1,000 psf. The risk of settlement is if the bearing soils were to become
wetted and precautions such as positive surface drainage away from and limiting irrigation near
foundation walls should be taken to prevent wetting. Prior to the footing construction, any loose
disturbed soils should be removed and the subgrade re-compacted as needed. Other
recommendations presented in our previous report which are applicable should also be observed.
The recommenclations submitted in this letter are based on our observation of the soiis exposed
within the foundation excavation and the previous subsurface exploration at the site. Variations
in the subsurface conditions below the excavation could increase the risk of foundation
movement. We should be advised of any variations encountered in the excavation conditions for
possible changes to recommendations contained in this letter.
If you have any questions or need further assistance, please call our office.
Sincerely,
H-Pt KU
David A. Young, P.E
DAYlkac
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attachment Figure 1, Swell-Consolidation Test Results
Garfield County Building Dept. - Jim Wilson (jwilson@garfield-county.coml
H.P*KUIVIAR
Project No. 17-7-460.01
SAMPLE OF: Very Sondy Sili
FROM: Bollom of Excovotion
\NC = 7.4 %, DD = 99 pcf
AODITIONÂL COMPRESSION
UNDER CONSTANT PRESSURE
DUE TO WETTING
:
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full, ribÒut tnr sdlt.r opprôvdr óf
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17 -7 -460.01 H.PryKUMAR SWELL-CONSOLIDATION TEST RTSULTS Fig. 1