HomeMy WebLinkAboutObservation of Excavation 11.02.22rcn ftrmr&Affimq,hc"'
Geotechnical and Maledals Engineas
and Environmental Scientists
An Emdoltas (}tmcd Cornpony
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
November 2,2022
Terry Thompson
233 Vaquero Road
Carbondale, Colorado 81623
terr.v @thomp sonfr amer. com
Project No. 21-7-901
Subject: Observation of Excavation, Proposed Residence, Lot 14, Callicotte Ranch, Sopris
Lane, Garfield County, Colorado
Dear Terry:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on November I,2022 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 January 13,2022, Project No. 21-7-901.
At the time of our visit to the site, the foundation excavation had been cut in 3 levels up to 6 feet
below the adjacent ground surface. The eastern portion ofthe house had been filled up to 3 feet
above the surrounding terrain. The fill appeared tobe 3/o inch road base and reported to have been
compacted with a Iarge, ride-on, vibratory compactor. To our knowledge, no density testing of
the filI was performed as it was placed. The natural soils exposed in the bottom of the
excavation consisted of mostly brown, stiff, sandy silty clay in the central part of the main
excavation. The soils in the garuge excavation, on the north side of the house, consisted of
relatively dense, basalt rocks in a whitish sandy silt matrix. The basalt rocks in the white sandy
silty matrix soils were also present in the southwest and west parts of the excavation. No free
water was encountered in the excavation and the soils were slightly moist to moist. Some
organic topsoil material was observed in the south-central part of the apparent building area but,
as the building had not been staked, this may have been outside the building area.
The natural 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 2,000 psf. There could be some differential settlement between footing)
bearing on the natural soils and footings bearing on structural fill. Loose and disturbed soils
should be moistened and compacted or 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
Terry Thompson
November 2,2022
PageZ
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,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 concemed 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,
Daniel E. Hardin,
Rev. by: SLP
DEHlkac
Kumar & Associates, lnc. @ Project No. 21-7-901