HomeMy WebLinkAboutObservation of Excavation 05.03.20231(+AGeotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumamsa.com
An Employee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
May 3, 2023
James Martinez
1055 County Road 255
Rifle, Colorado 81650
jartinez(a)martinezconstruction.com
Project No. 22-7-164.A
Subject: Observation of Excavation, Proposed Cabin, West of 1777 County Road 241,
East Elk Creek Road, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on April 24, 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 April 19, 2022, Project No. 22-7-164.
We understand the proposed cabin is to be founded on spread footings bearing on the natural
bedrock and sized for an allowable bearing pressure of 3,000 psf.
At the time of our visit to the site, the foundation excavation had been cut in one level from 4%2
to 9 feet below the adjacent ground surface. The material exposed in the bottom of the
excavation consisted of broken hard natural sandstone bedrock. No free water was encountered
in the excavation and the subsurface materials 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 3,000 psf. Loose and disturbed rock should be removed in the footing areas
to expose the undisturbed natural bedrock. 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 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.
James Martinez
May 3, 2023
Page 2
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, Ir
Robert L. Duran, P.E.
Rev. by: DEH
RLD/kac
Kumar & Associates, Inc. 0 Project No. 22-7-164.A