HomeMy WebLinkAboutObservation of Excavation 06.14.2024rcn l(umr & Associates, lnc.@
Geotechnical and Materials Engineers
and Environmental Scientists
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
ernail : kaglenwood@kumarusa.com
www.kumarusa.comAn Employcc Ourncd Compony
Office l,ocations: Deirver (HQ), Parker, Colorado Springs, Fort Collins. Glenwood Springs, and Summit County, Colorado
June 14,2024
Btech Construction
Attn: Joaquin Bianco
P.O. Box 811
Silt, Colorado 81652
btechconstructi on@hotmail. com
Project No. 23-7-174.A
Subject: Observation of Excavation, Proposed Residence, 897 County Road 231, Garfield
County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on June 4, 2024 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 foundations at the site, report dated
May 8, 2023, Project No. 23-7-174 and observed the shop excavation soil conditions, report
dated June 28, 2023, Project No.23-7-1744.
The proposed residence has been designed to be supported by spread footings placed on at least
3 feet of compacted structural filI and sized for an allowable bearing pressure of 1,500 psf with
a settlement risk.
At the time of our site visit, the foundation excavation had been cut in 1 level about 4 to 7 feet
below the adjacent ground surface, including the 3 feet of sub-excavation depth. The soils
exposed in the bottom of the excavation consisted of sandy silt. Results of swell-consolidation
testing performed on a sample taken from the cut depth, shown on Figure 1, indicate the natural
soils are relatively low density and moderately compressible under conditions of loading and
wetting. No free water was encountered in the excavation and the soils were slightly moist.
We are in the process of perlorming in-place density testing on the structural fill placed below
footing areas and the compaction results will be reported separately.
The soils exposed in the excavation and subsequent properly compacted structural filI are
consistent with those recommended for support of spread footings designed for the
recommended allowable bearing pressure of 1,500 psf. Other recommendations presented in
our previous report which are applicable, especially those to keep the bearing soils dry, should
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. We should be advised of any variations encountered in the excavation
Btech Construction
June 14,2024
Page2
conditions for possible changes to recommendations contained in this letter. Our services do
not include determining the presence, prevention orpossibility ofmold or other biological
contaminants (MOBC) developing in the future. If the client is concsmed about MOBC, then
a professional in this special field of practice should be consulted.
If you have any questions or need further assistanceo please call our office.
Sinc,erely,
Kumar & Associatee,
Steven L. Pawlak,
SLP/kac
Attachment:Test ResultsFigure I
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Kumar & Associates, lnc. o Project No.23-7-174.A
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SAMPLE OF: Sondy Silt
FROM: Boilom of Excovoiion
WC = 5.0 )6, DD = 65 pcf
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ADDITIONAL COMPRESSION
UNDER CONSTANT PRESSURE
DUE TO WETTING
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23-7 -17 4.A Kumar & Associates SWELL-CONSOLIDATION TEST RESULTS Fig. 1