HomeMy WebLinkAboutObservation of Excavation 06.15.20231(+AGQRgffi & al and 8te8,;t16.0
Geotechninical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
Z� email: kaglenwood@kumarusa.com
An Employee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
June 15, 2023
Patrick Westfeldt
158 Wild Rose Drive
Glenwood Springs, Colorado 81601
p atrickbwestfeldt(d)gmail. com
Project No. 21-7-186
Subject: Observation of Excavation, Proposed Residence, Lot 114, Ironbridge, 295 Silver
Mountain Drive, Garfield County, Colorado
Gentlemen:
As requested by Jay Billington, a representative of Kumar & Associates, Inc. observed the
excavation at the subject site on June 15, 2023 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 April 14, 2021, Project No. 21-7-186.
The proposed residence is generally consistent with that described in our previous report and
includes a detached garage in the middle of the lot with the residence in the eastern area. Spread
footings placed on the natural gravel soils and sized for an allowable bearing pressure of 3,000
psf were recommended for the foundation support.
At the time of our visit to the site, the residence excavation had been cut in multiple levels from
about 2%2 to 3 feet below the adjacent ground surface. The steps in grade were about 1 to 1 Meet
between levels at the downhill, east side. The garage foundation excavation had been cut in one
level from about 1 %2 to 3 feet below the adjacent ground surface. The soils exposed in the bottom
of the residence excavation consisted of sandy gravel with cobbles and in the bottom of the
garage excavation consisted of silty clay. No free water was encountered in the excavation and
the soils were slightly moist to moist.
The soils exposed in the excavations are consistent with those previously encountered on the site.
The gravel soils are suitable for support of spread footings designed for the recommended
allowable bearing pressure of 3,000 psf. The clay soils can support spread footings designed for
an allowable bearing pressure of 1,500 psf which the structural engineer should confirm the
suitability of their design for the lower bearing pressure. Loose disturbed soils should be
compacted or removed in the footing areas to expose the undisturbed natural soils. 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 subsurface exploration at the site. Variations
in the subsurface conditions below the excavation could increase the risk of foundation
Patrick Westfeldt
June 15, 2023
Page 2
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. �"no REP�� l
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Steven L. Pawlak, P. �9/ j4,/2-3
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cc: JDB Construction - Ja gton (jdbcon@yahoo.com)
Kumar & Associates, Inc. Project No. 21-7-186