HomeMy WebLinkAboutExcavation of Observation 05.16.20231(+AKumar & Associates, Inc. 0
Geotechnicai 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
An Employee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
May 16, 2023
Ryan Blake
10862 Cottage Drive
Hanover, Minnesota 55341
Rblakel9(cohotmail.com
Project No. 17-7-697.A
Subject: Observation of Excavation, Proposed Residence, Lot 43, Filing 4B, Phase 2,
Oak Meadows, 657 Old Midland Spur, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on May 16, 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 October 30, 2017, Project No. 17-7-697.
We understand the proposed residence has been designed to be founded on spread footings
bearing on at least 3 feet of compacted structural fill placed on the native sandy clay soil. The
spread footings have been sized for an allowable soil bearing pressure of 2,500 psf with a 500 psf
minimum dead load.
At the time of our visit to the site, the foundation excavation had been cut in 2 levels from 3 to
12 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of very stiff sandy clay. 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 placed on 3 feet of structural fill and
designed for the recommended allowable bearing pressure of 2,500 psf with a minimum 500 psf
deadload. Loose and disturbed soils should be 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. Non-structural floor slabs should be placed on at least 2 feet
of structural fill. Structural fill placed beneath footings should consist of 3/-inch road base and
be compacted to at least 98 percent of the standard Proctor density at a moisture within 2 percent
of optimum. Structural fill placed beneath floor slabs should be compacted to at least 95 percent
of the standard Proctor density at a moisture within 2 percent of optimum. We should test
structural fill for compaction during placement.
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
Ryan Blake
May 16, 2023
Page 2
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.
R
Robert L. Duran, P 57322
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cc: Wild Trout Enterprises — Miguel Rojo (Miguel(&WildTroutEnterprises.com)
Kumar & Associates, Inc. @ Project No.17-7-697.A