HomeMy WebLinkAboutObservation of Excavation 06.15.23Kt f*iffilflff:llffi1rls'i*'"
An Employcc Owncd ComPonY
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email : kaglenwood@kumarusa.com
www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
June 15,2023
Juan Suarez
37l l Grass Mesa Road
Garfield County, Colorado 81650
Project No. 23-7-356
Subject: Observation of Excavation, Proposed Residence, LoI44, Grass Mesa Ranch,
3711 Grass Mesa Road, Garfield County, Colorado
Juan:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on June 14, 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.
Hepworth-Pawlak Geotechnical (now Kumar & Associates) previously conducted a preliminary
subsoil study on Lot 44 for foundation design and presented the findings in a report dated
October 12,2007, Job No. 107 377 .
The proposed residence will be a single-story structure with slab-on-grade floor. Spread footings
placed on the natural soils and sized for an 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 one level ftom2l/,
to 4% feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of calcareous, silty clayey sand and gravel with cobbles and scattered boulders. The
excavation was rough cut and around lzto I foot of loosened material covered the excavation
bottom. No free water was encountered in the excavation and the soils were slightly moist.
The natural soils exposed in the excavation bottom (below the loosened soils) are consistent with
those previously encountered on the site and suitable for support of spread footings designed for
the assumed allowable bearing pressure of 1,500 psf. The loose disturbed soils should be
removed to expose the undisturbed natural soils or moistened and compacted to atleast95o/o
standard Proctor density. 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
Juan Suarez
June 15,2023
Page2
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, lnc.
Steven L. Pawlak,
SLPlkac
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Kumar & Associates, lnc. @ Project No, 23-7-356