HomeMy WebLinkAboutObservation of Excavation 7.14.2022'(+AKamer &Associates, Inc.®
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 Compony www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
July 14, 2022
Russell Cartwright
35 Willowview Way
Parachute, Colorado 81635
russecart@gmail.com
Project No. 22-7-176.01
Subject: Observation of Excavation, Proposed Residence, Lot 13, Block 7, Willow Creek
Section 1, 48 Ridge View Place, Battlement Mesa, Garfield County, Colorado
Dear Russell:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on July 5, 2022 to evaluate the soils exposed for foundation support. The findings of our
observations and recommendations are presented in this report. The services are supplemental to
our agreement for professional services to you dated February 10, 2022.
We previously prepared a subsoil study for design of foundations at the site and presented our
findings in a report dated April 7, 2022, Project No. 22-7-176. The proposed construction is
similar to that discussed in our previous report. Spread footings sized for an allowable soil
bearing pressure of 1,200 psf were recommended for foundation support with some risk of
settlement.
At the time of our site visit, the foundation excavation which was essentially complete had been
cut in one level from about 1 to 4 feet below the adjacent ground surface. There was minor cut
in the garage floor slab area. The soils exposed in the bottom of the excavation consisted of stiff,
slightly sandy occasionally clayey silt. The excavation subgrade had been moistened and
compacted. Results of swell -consolidation testing performed on samples taken from the site,
shown on Figure 1, indicate the soils are moderately compressible under conditions of loading
and wetting with a low hydro -compression potential. 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 1,200 psf. The risk of settlement is primarily if the bearing soils were to
become wetted with depth and precautions should be taken to prevent wetting. Prior to the
footing construction, any loose and disturbed soils should be removed in the footing areas to
expose the undisturbed natural soils and the subgrade re -compacted as needed. 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
Russell Cartwright
July 14, 21722
Page 2
movement. We should be advised of any variations encountered in the excavation conditions for
possible changes to recommendations contained in this letter.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Assoeia4es. Inc.
o 6216
David A. Young, P. •
DAY/kac Gam•••
SSS.....4
attachment Figure
Test Results
Kumar & Associates, Inc. ' Project No. 22-7-176.01
SAMPLE OF: Slightly Sandy Silt
FROM: Bottom of Excavation
WC = 6.0 %, DD = 95 pcf
1
ADDITIONAL COMPRESSION
UNDER CONSTANT PRESSURE
DUE TO WETTING
..
0
X
J
J
—1
IBJ
N
—2
Z
O
H
Q
o
—
3
J
O
1n
Z
O
—4
—5
0
—6
I
N
—
`
These test results apply only to the
samples tested. The testing report
i
shall not be reproduced, except in
full, without the written approval of
Kumar and Associates, Inc. Swell
Consolidation testing performed in
—
accordance with ASTM D-4546.
.1
1.0
APPLIED PRESSURE - KSF 10 100
z
0
o
°s
s
N
N
4 22-7-176.01
Kumar & Associates
SWELL—CONSOLIDATION TEST RESULTS
Fig. 1