HomeMy WebLinkAboutObservation of Excavation 09.22.2021I(+'I
An Employcc Owncd Compony
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
www.kuma¡usa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, ærd Summit County, Colorado
September 22,2021
Matt Ringer
7315 County Road 312
New Castle, Colorado 81647
mmrinser2l@qmail'com
projectNo ,21-7-321
Subjecil Observation of Excavationo Proposed Residence, 7315 County Road 312,
Garfield County, Colorado
Matt:
As requestedo a representative of Kumar & Associateso Inc. observed the excavation at the
subject site on September 17,2021to evaluate the soils exposed for foundation support. The
findings of our observations and recommendatíons for the foundation design are presented in this
report. We previously conducted a subsoil study for design of fowrdations at the site ard
presented our findings in areport dated May l2,2AZl, Project Na' 2l-7'321.
The residence design is essentially the same as described in our previous report. Spread footings
placed on the natural soils were designed for the foundation support.
At the time of our visit to the site, the foundation excavation had been cut in multþle levels from
about 4 to I feet below the adjacent ground surface. The soils exposed in the bottom ofthe
excavation were variable and consisted of very stiffto hard clay in cut ateas less than about
6 feet deep and clayey sand and gravel in deeper cut areas. Results of swell-consolidation testing
performed on a sample of clay taken from the síte, shown on Figure l, indioate the soils are
moderately expansive under conditions of loading and wetting. No free water was encountered
in the excavation and the soils were slightly moíst.
The soil çonditions exposed in the excavation are consistent with those previously çncountered
on the site and the gravel soils are suítable for support of spread footings designed for the
recommended allowable bearing pressure of 2,500 psf. The clay and loose distrnbed soils should
be removed from footing areas to expose the gravelly 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 exçavation could increase the risk of foundation
movement We should be advised of any variations encountered in the excavatìon conditions for
possible changes to recommendations contained in this letter. Our services do not include
determining the presence, prevention CIrpossibility of mold or other biological contaminants
Kumar & Associates, lnc.@
Geotechnical and Materials Engineers
and Environmental Scientists
Matt Ringer
Septernber 22,2021
Page2
(MOBC) developing in the future. If the client is concerned aboutMOBC, then a professional in
this special field ofpractice should be consulted.
If you have any questions or need further assistance, please call or¡r office.
Sincerely,
Kumar & Associates, lnc.
Stwen L. Pawlak, P
SLP/kac
Attachment: Figure I Test Rezults
Kumar & Associates, lnc.6)Project No.2'l-7-321
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SAUPLE OF: Sondy €lcy
FROII: Bstfom of Norlhwest Corner fooling Pod
Excovollon
WC = 8.8 X, DD = f 11 pcf
EXPANSION UNDER CONSTANT
PRESSURE UPON WETTING
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21-7-321 Kumar & Associates SWELL-CONSOLIDATION TEST RESULTS Fig. 1
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