HomeMy WebLinkAboutObservation of Excavation 04.12.24I (frA *iffilfi'trtf*"lrtrf [$i *' "
An Employee Orned Compony
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
April 12,2024
Rudd Construction
Attn: Chris Jung
0132ParkAvenue
Basalt, Colorado 81621
chris@ruddconstruction.com
Project No. 17-7-858.A
Subject: Observation of Excavation, Proposed Building C, Cattle Creek Center, Garfield
County, Colorado
Dear Chris:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on April4, 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 7,2024, Project No. 17-7-858.
Building C is the northeast building of the group of 4 buildings in the main complex of buildings.
This area was filled to existing grade in the year 2000. The fill was placed for future building
foundation support and tested for compaction during placement. Strip footings placed on the
existing fill and sized for an allowable bearing pressure of 2,000 psf were designed for the
foundation support.
At the time of our visit to the site, the foundation excavation had been cut in two levels from
nil to 7 feet below the adjacent ground surface. The fill soils exposed in the bottom of the
excavation mainly consisted of sandy silt and clay with scattered gravel and cobbles. The results
of a gradation analysis performed on a sample of the fill soils (minus 3-inch fraction) obtained
from the site are presented on Figure 1 No free water was encountered in the excavation and
the soils were slightly moist to very moist.
The soil conditions exposed in the excavation are consistent with those expected at the site and
suitable for support of spread footings designed for the assumed allowable bearing pressure of
1,500 psf. Loose distr"rrbed soils and water softened areas in the footing areas should be
moistened and compacted. The bearing soils should be protected from frost and concrete should
not be placed on fi'ozen soils. Other recomlnendations 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 review of bearing soils 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
Rudd Construction
April12,2024
Page2
(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, lnc.
James H. Parsons, P.E.
Rev. By RLD
JHPlkac
attachments Figure 1 - Gradation Test Results
Table I - Summary of Laboratory Test Results
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Kumar & Associates, lnc. @ Project No. i7-7-858.A
I(+A lfumar & Associates, lnc."
Geotechnical and Materials Engineers
and Environmental Screntisls
TABLE 1
SUMMARY OF LABOMTORY TEST RESULTS
No.17-7-858,A
East Side
IN BOTTOM OF EXCAVATION
SAMPLE LOCATION
18.4
lolol
NATURAL
MOISTURE
CONTENT
locfl
NATURAL
DRY
DENSITY
5
(%)
GRAVEL
34
SAND
{%)
GRADATION
6 I
PERCENT
PASSING NO.
200 stEVE
t%l
LIQUID LIMIT
(%l
PLASTIC
INDEX
ATTERBERG LIMITS
PSF)
UNCONFINED
COMPRESSIVE
STRENGTH
Sandy Silt and Clay with
Scattered Gravel
sotL oR
BEDROCK TYPE
q
I
I
II
E
9
I
E
I
SIEVE ANALYSIS
CLEAR SQUARE OPENINGS
?/e, 1/Ar 1 1/rn
U.S. STANOARO SERIES
r6n lra ttd tt6 lio 18
HYDROMETER ANALYSIS
=
r00
90
80
70
60
50
40
30
20
10
o
o
10
20
30
40
5o
50
70
80
90
100
=b
.1 50 .300 I .600
.425
PARTICLES
.1 I 127 200
152
DIAMETER OF IN MI
CLAY TO SILT COBBLES
GRAVEL 5 % SAND 34 %
LIQUID LIMIT - PLASTICITY INDEX
SAMPLE OF: Sondy Sill ond Cloy with Scoltered Grovel
Slll ANU LUI Ol /6
FROM: Eosl Side of Boltom of Excovotion
Th€se l€sl r€sulls dpply only lo lh€
somplos which w€rs lssled. Tho
t€stldg r€port sholl not ba raproduced,
6xc€pt ln full, wllhoul lhe wrlll€n
opprovol of Kumor & Assoclolos, lnc.
Sisv€ qnqlysis losling is p.rformed ln
occordoncc wllh ASTM D6915, ASTM 07928,
ASTII 11136 dhd/nr ASTM nllto.
GRAVELSAND
COARSEFINEMEDTUM lCOlnSr FINE
1 7-7-8584 Kumar & Associates GRADATION TEST RESULTS Fig. 1