HomeMy WebLinkAboutObservation of Excavation 04.29.2025I (+A $;,ffii'Ttrtrtr1'"'rd*'
*5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email : kaglerrwood@kumarusa.com
An Emdoyct O{mtd Compony www'kumarusa'com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
Aprll29,2025
Coiorado Energy Systems
Attn: Ian Moritz
27 4 Mountain Shadows Drive
Glenwood Springs, Colorado 81601
ian@coloradoenergysystems. com
Project No. 25-7-281
Subject: Observation of Excavation, Proposed Second Story Addition,274 Mountain
Shadows Drive, Glenwood Springs, Colorado
Dear lan:
,{s requested, a representative of Kumar & Associates observed the excavation at the subject site
o;r dpril 18, 202.5 to evaluate the soils exposed for foundation support. The findings of our
*bser,'ations arrd recommendations for the foundation support are presented in this repod. The
seivices were per{bnned in accordance with our agreement for professional engineering services
trr Ccrioraclo Energy Systems dated April t5,2025.
T'he secocd story addition is proposed to be supported on two isolated footing pads sized for an
a.lJowabie bearing pressure of 1,600 psf. The addition will not have ground level development
belorv and r,o,'ill be supported on structural steel and wood elements.
Ar t-he tiine of our visit to the site, two pad excavations had each been cut to between 3 and
3). feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of firm, sandy clay and gravel. Results of swell-consolidation testing performed on a
sample taken lrorn the site, shown on Figure 1, indicate the soils have low to moderate
c;cmpressibility under conditi<-rns of loading and wetting. The results of a gradation analysis
pei'formed on a sample of sandy clay and gravel (minus 3-inch fraction) obtained fiom the site
are presented on Figure 2. No free water was encountered in the excavation and the soils were
slightly moist.
Considering the conditions exposed in the excavation and the nature of the proposed
construction, spread footings placed on the undisturbed natural soil designed for an allowable
soil bearing pressure of 1,600 psf should be adequate for support of the proposed addition. The
exposed soils tend to compress when wetted and there could be some post-construction
settlement of the foundation especially if the bearing soils become wet. Footings should be a
minimum width of 2 feet for columns. Loose and disturbed soils in footing areas should be
removed and the exposed soils moistened and compacted. Exterior footings should be provided
wirh adequate soil cover above their bearing elevations for frost protection. Backfill should be
compacted and the surface graded to drain away from the new pads.
Colorado Energy Systems
Apri|29,2025
Page2
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and do not include subsurface exploration to evaluate the
subsurface conditions within the loaded depth of foundation influence. This study is based on
the assumption that soils beneath the footings have equal or better support than those exposed.
The risk of foundation movement may be greater than indicated in this report because of possible
variations in the subsurface conditions. In order to reveal the nature and extent of variations in
the subsurface conditions below the excavation, drilling would be required. It is possible the
data obtained by subsurface exploration could change the recommendations contained in this
letter.
If you have any questions or need further assistance, please call our office.
Sincerely,
Wasmay &. &*a*aia\w%, t{,c,
James H. Parsons,
Rev. by: SLP
JHFlkac
attachments Figure 1 - Swell Consolidation Test Results
Figure 2 - Gradation Test Results
Kumar & Associates, lnc. o Project No. 25-7-281
SAMPLE OF: Sondy Cloy ond Grovel
FROM: Footing Grode - Eosl Pod
WC = 1 5.3 %, DD = 105 pcf
(
innot be Gproducod,
te8ted. Ths
NO MOVEMENT UPON
WETTING
1
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-3
-4
-5
-6
1.0 APPLIED PRESSURE - KSF t0 100
25-7 -281 Kumar & Associates SWELL_CONSOLIDATION TEST RTSULTS Fig. 1
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100
90
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70
60
50
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20
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20
50
40
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IN MILLIMETERS
152
DIAMETER OF PA
CLAY TO SILT COBBLES
GRAVEL 33 % SAND 23
LIQUID LIMIT
SAMPI.E OF: Sondy Cloy ond Grovel
%
PLASTICITY INDEX
SILT AND CLAY 44%
FROM: Fooling Grode - East Pod
lhoso tesl rEsulls opply only lo lh6
somplos whlch werE l6sl€d. The
trsllng roporl sholl nol bs reproduced,
€xcept ln lull, wllhoul lho wrlll€n
qpprovol of Kumor & Assoclol.s, lno.
Sl€vo onolysis l6sling ls psrformed in
occordonco wlth ASTM D6913, ASTM D7928,
ASTM Cl56 ondlor ASTM Dl140.
HYDROMETER ANALYSIS SIEVE ANALYSIS
TIME READINES
24 HRS 7 HRS
Ittltt
I
SAND GRAVEL
FIN E MEDTUM lCOlnSr FINE COARSE
25-7 -281 Kumar & Associates GRADATION TIST RESULTS Fig. 2