HomeMy WebLinkAboutObservation of ExcavationKumar & Associates, Inc.
'C 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@kumarusa.com
An Employee Uwned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
January 23, 2024
Domoplex, LLC
Attn: Slawek Wojciuch
2550 Highway 82, Unit 108A
Glenwood Springs, Colorado 81601
slawek(u,domoplex.com
Project No. 22-7-297.A
Subject: Observation of Excavation, Proposed Residence, Lot 51, Filing 9, Elk Springs,
0071 Vista Place, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on January 19 and 22, 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 and
presented our findings in a report dated May 20, 2022, Project No. 22-7-297.
We understand the proposed residence has been designed to be founded on spread footings
bearing on the natural soils or compacted structural fill and sized for an allowable bearing
pressure of 2,500 psf.
At the time of our visit to the site on January 19, 2024, the foundation excavation had been cut in
multiple levels from 3 to 8 feet below the adjacent ground surface. The excavation had been
overdug from %2 to 3 feet below footing elevations due to the removal of large boulders. The
material exposed in the bottom of the excavation consisted of basalt rock with sandy silt and
basalt gravel. No free water was encountered in the excavation and the soils were slightly moist.
Imported 3-inch minus aggregate base course from Western Slope Materials was being placed to
re-establish design footing grade.
At the time of our visit to the site on January 22, 2024, design footing grade had been re-
established with up to 2 feet of compacted 3-inch minus aggregate base course and the upper
6 to 8 inches with compacted 3/-inch aggregate base course. A ground heater and blankets had
covered the excavation over the weekend. Four nuclear density gauge tests were performed on
the 3/-inch base course with dry densities ranging from 133.3 pcf at 5.7 percent moisture content
to 135.7 pcf at 7.9 percent moisture content. Based on the compaction test results, the
compaction of the base course was judged to be adequate for support of the proposed footings.
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 2,500 psf. The bearing soils should be protected from frost and concrete
Domoplex, LLC
January 23, 2024
Page 2
should not be placed on frozen 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
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.
Robert L. Duran, P
Rev by: DEH
RLD/kac
573221
Kumar & Associates, Inc. 0 Project No. 22-7-297.A