HomeMy WebLinkAboutObservation of Excavation 09.12.24Kumar & Associates, Inc.®
K Geotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone. (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
An Employee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
September 12, 2024
Uriel Mellin
144 Cliffrose Way
Glenwood Springs, Colorado 81601
uri el.mellin(a,hotmail. com
Project No. 24-7-514
Subject: Observation of Excavation, Proposed Apartment and Commercial Building,
252 County Road 167, Garfield County, Colorado
Dear Uriel:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on September 3, 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 for a nearby building
and presented our findings in a report dated March 26, 2019, Project No. 19-7-171. The current
observation was conducted in accordance with our agreement for professional engineering
services to you dated August 29, 2024.
The proposed building will be a single -story wood -frame building over a full depth basement
level. The building will have commercial spaces on the ground floor and residential spaces at
the basement level. The building has been designed to be supported on spread footings placed
on the native gravel soils and sized for an assumed allowable soil bearing pressure of 3,500 psf.
At the time of our visit to the site, the foundation excavation had been cut in one level from 7 to
10 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted primarily of dense, silty sandy gravel with cobbles. Under the stairwell excavation
stiff to very stiff sand and silt was exposed. The sand and silt soils possess a low bearing
capacity and typically low settlement potential for the assumed shallow depth above the gravel
soils. We recommended the stairway be redesigned for an allowable bearing capacity of 1,500
psf or the excavation be deepened to expose natural gravel soils. No free water was encountered
in the excavation and the soils were slightly moist to moist.
The soil conditions exposed within the primary building area of the excavation are consistent
with those previously encountered on the nearby site and suitable for support of spread footings
designed for the assumed allowable bearing pressure of 3,500 psf. The sand and silt soils can be
used for support of spread footings designed for an allowable bearing pressure of 1,500 psf with
a risk of settlement. Loose disturbed soils should be removed in the footing areas to expose
the undisturbed natural soils. Other recommendations presented in our previous report which
are applicable should also be observed.
Uriel Mellin
September 12, 2024
Page 2
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 nearby 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.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates,
James H. Parsons, P
Rev. by: SLP
JHP/kac
Kumar & Associates, Inc. 0 Project No. 24-7-514