HomeMy WebLinkAboutObservation of Excavationrcn tliltr&Arsûclfr¡,he."
Geotechnical and Maledals Engineers
and Environmental Scientists
An Employce Oumad Gompony
5û20 County Road i54
Clenwr¡od S¡rrings, CO 81601
phone: {97û) 945-1988
fax {97A} 945-8454
emaii : kaglenwood@kurnarusa.çùnl
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Of ice Locations: Denver (HQ), Parker,Colorado Springs,Fort Collins,Clenwood Springs, and
December 18,2020
Burkholder Homes
Attn: Todd Burkholder
P.O. Box 400
Carbondale, Colorado 81623
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Project No. 20-7-390.4
Subject: Observation of Excavation, Proposed Harper Residence, Lot 69, Ironbridge
Phase 2, River Bend Way, Garfield County, Colorado
Gentlemen,
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on December 14ft and I7'ú,2020 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 August 3,2020, Project No. 20-7-390. The
current observations were performed in accordance with our agreement for professional services
with Burkholder Homes dated December 13,2020.
At the time of our initial visit to the site, the excavation was in progress and the eastern part of
the excavation had been cut to design grades. 'When observed on December lTth the foundation
excavation had been cut to multiple levels from 13 feet to 5 feet below the adjacent ground
surface with depth decreasing toward the north and east. At all foundation levels the excavation
exposed a dense, slightly silty, sandy gravel and cobble soil. No free water was encountered in
the excavation and the soils were slightly moist.
The gravel 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
reconunended allowable bearing pressure of 2,500 psf. Any loose and disturbed soils should be
removed in the footing areas to expose the undisturbed natural soils prior to the placement of
concrete. The bearing soils should be protected against frost, and concrete should not be placed
on frozen soils. Other recorlrmendations 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
movement. We should be advised of any variations encountered in the excavation conditions for
Burkholder Homes
December 18,2020
Page2
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
(MOBC) developing in the future. If the client is concemed about MOBC, then a professional in
this special field ofpractice should be consulted.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, Inc.
ÀJìb ll"t'
David Noteboom, Staff Engineer
Reviewed by:
Steven L. Pawlak, P
SLP/kac
Kumar & Associates, lnc. 6l Project No.20-7-390.4