HomeMy WebLinkAboutObservation of Excavation 12.15.20211(+A Geotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumamsa.com
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Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
December 15, 2021
Red House Architecture
Attn: Bruce Barth
815 Blake Avenue
Glenwood Springs, Colorado 81601
brucenredhousearchitecture. com
Project No. 21-7-455.A
Subject: Observation of Excavation, Proposed Residence, Lot RR3, Filing 8, Elk Springs,
620 Juniper Drive, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on November 30, 2021 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 and
presented our findings in a report dated June 24, 2021, Project No. 21-7-455.
The proposed residence location and design are essentially the same as shown in our previous
report. Spread footings placed on the natural soils and sized for the recommended allowable
bearing pressure of 1,500 psf were designed for the foundation support.
At the time of our visit to the site, the foundation excavation had been cut in multiple levels from
about 1 to 6 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of mainly silty sandy clay. Large basalt boulders were encountered in the
west wing and the resulting depressions had been backfilled with road base to design footing
grade. Compaction testing was attempted but due to frozen condition, the testing could not be
completed and the subgrade will need to be thawed. No free water was encountered in the
excavation and the clay soils were slightly moist.
Red House Architecture
December 15, 2021
Page 2
The natural clay soils 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 1,500 psf. Loose disturbed soils should be removed in the footing areas to
expose the undisturbed natural soils. The bearing soils should be protected from frost and
concrete should not be placed on frozen soils. The backfilled areas should be evaluated for
compaction when completely thawed out. Other recommendations presented in our previous
report which are applicable 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
conditions for possible changes to recommendations contained in this letter. Our services do not
include determining the presence, prevention or possibility of mold or other biological
contaminants (MOBC) developing in the future. If the client is concerned about MOBC, then a
professional in this special field of practice should be consulted.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, Inc.
RE
Steven L. Pawlak, P.E. Ica 15222 •
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