HomeMy WebLinkAboutObservation of Excavation 02.17.23
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
1 Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
February 17, 2023
Jose Gonzales
P.O. Box 2544
Glenwood Springs, Colorado 81602
dspincorporated@gmail.com
Project No. 21-7-222
Subject: Observation of Excavation, Proposed Residence, Lot 2, Dunlap Minor
Subdivision, Jewell Lane (CR 259), Garfield County, Colorado
Dear Mr. Gonzales:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on January 13, 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 May 11, 2021, Project No. 21-7-222.
The proposed residence will be a one-story wood frame structure over a crawlspace.
Foundations were designed for an allowable soil bearing pressure of 4,000 psf with a
minimum dead load of 1,000 psf based on our previous subsoil study.
At the time of our visit to the site, the foundation excavation had been cut in one level from 1½
to 3 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of medium dense, silty gravelly sand in the northwest half of the excavation and stiff,
sandy clayey silt in the southeastern half of the excavation. Results of swell-consolidation
testing performed on a sample of the sandy clayey silt taken from the northwestern part of the
site, shown on Figure 1, indicate the soils are low to moderated settlement potential under
conditions of loading and wetting. The results of a gradation analysis performed on a sample of
the silty gravelly sand (minus 1½-inch fraction) obtained from the southeastern part of the site
are presented on Figure 2. 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 designed for the recommended allowable
bearing pressure of 4,000 psf with a minimum dead load of 1,000 psf. Loose and disturbed soils
should be 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 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.
Kumar & Associates
Kumar & Associates