HomeMy WebLinkAboutObservation of Excavation 11.11.2022l(+-rt Kumar & Associates, lnc.''o
Geotechnical and Materiãls Ertgineers 5020 County Road 154
and [nvironrnenlal Scientìsls Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email : kaglenwood@kumarusa.com
&.nämplc,YøêQwnødÇçwrpanywvwv.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
November 11,2022
Frank Fraser
0719Road225
Rifle, Colorado 81650
fiasergaragef@,srn ai1 . c onl
Project No.22-7-713
Subject.Observation olExcavation, Proposed Garage Building, 07 l9 Road 22-5 (Antlers
Lane), Garfield County, Colorado
Mr. Fraser
As requested, a representative of Kumar & Associates obserued the excavation at the subject site
onNovemberT.2022toevaluatethesoilsexposedforfoundationsupport. Thefindingsofour
obseryations and recommendations for the foundation supporl are presented in this report. The
services were performed in accordance with our agreement for professional engineering services
to you dated November 3, 2022
The proposeci steel builcling will be 40'x4O' in plan size and supported on a monolithic structural
slab foundation with turn-down edges insulated against frost penetration. An allowable soil
bearing pressure of I,500 psf is designated lor the foundation support.
At the time of our visit to the site, the building excavation had been cut in one level with the
perimeter turn-down edge depth of one-foot. The soils exposed in the bottom of the excavation
consisted of very sancly silty clay. Results of swell-consolidation testing perfbrmed on a sample
taken from the site, shown on Figure 1, indicate the soils are slightly to moderately compressible
under conditions of loading and wetting. No free water was encountered in the excavation and
the soils were moist.
Considering the conclitions exposed in the excavation and the nature of the proposecl
construction, spread fbotings/structural slab placed on the undisturbed natural soil designed for
an allowable soil bearing pressure of 1,500 psf should be adequate for support of the proposed
building. The exposecl soils tend to compress when wetted under load and there could be some
Frank F-raser
November 11,2A22
Page 2
post-construction settletnent. The bearing soils should be protected against Íiost and concrete
should not be placed on frozen soils. Exterior footings should be provided with aclequate frost
protection' continuous fbundation walls/tum-down edges should be adequately reinforced to
span local anomalies both longitudinally and transverse into the structural slab. A perirneter
foundation drain should not be provided fbr the slab-at-grade design. Structural fill placed
within slab and pavement areas can consist of the on-site soils or imported road base cornpacted
to at least 95% of standard Proctor density at å moisture content near optimum. Landscape that
requires regular heavy in.igation, such as sod, an<l
10 feet of the fbundation.
sprinkler heads should not be located within
The recommendations submitted in this letter are based on our obseruation of the soils exposed
within the foundation excavation anci do not include subsurfüce exploration to evaluate the
sttbsurface 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 dsk of foundation movement may be greater than indicated in tl-ris 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 wourd be required. It is possible the
data obtained by subsurface exploration could change the recommendations contained in this
letter' our services do uot include determining the presence, prevention or possibility of mold or
other biological contaminants (MOBC) developing in the future, if the client is conce*ed 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,
Kunr¿¡r & Associateso
I;'-.1 ;
Steven L. Pawlak,
sLP/ljf
Attachment: Figure 1 * sweil-consoridation Test Resurts
(Í,15222
Kumar & Aseociatcs, lnc. a
Project No. Z2-T-713
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SAMPLE OF: Very Sondy Silty Cloy
FROM: Bottom of Excovoiion, Eosi Side
WC = 15,5 %, DD = 10J pcf
-200 = 54 %
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NO MOVEMENT UPON
WETTING
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22-7 -7 13 Kumar & Associates SWELL-CONSOLIDATION TEST RESULTS Fig. 1