HomeMy WebLinkAboutObservation of Excavation 08.08.24
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
August 8, 2024
Lindsay Gurley
1319 County Road 127
Glenwood Springs, Colorado 81601
lindsay@lindsaygurley.com
Project No. 21-7-112
Subject: Observation of Excavation, Proposed Residence, 1319 County Road 127,
Garfield County, Colorado
Lindsay:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on July 31, 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 February 5, 2021, Project No. 21-7-112.
The proposed residence will be constructed in place of the existing residence and is planned to be
supported by spread footings sized for the recommended allowable bearing pressure of 2,500 psf.
At the time of our visit to the site, the foundation excavation had been cut in one level from
about 1½ to 5 feet below the adjacent ground surface. The soils exposed in the bottom of the
shallower depth, southern part of the excavation consisted of silty clayey sand and gravel. The
northern part consisted of sandstone bedrock. Results of swell-consolidation testing performed
on a sample of the sand taken from the site, shown on Figure 1, indicate the soils have low to
moderate compressibility under conditions of loading and wetting. No free water was
encountered in the excavation and the soils were slightly moist to moist.
The soil and bedrock 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. There is a potential for differential
settlement between soil and bedrock cut areas due to the variable bearing conditions. Loose
disturbed soils in the footing areas should be removed and the exposed soils moistened and
compacted. 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 the recommendations contained in this letter. Our services do
Kumar & Associates