HomeMy WebLinkAboutObservation of Excavation 09.02.202011
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September 2, 2020
Don and Dee Moore
25 Buckskin Circle
New Castle, Colorado 81647
Project No. 19-7-705
Subject: Observation of Excavation, Proposed Residence, Lot 35, Four Mile Ranch,
225 Maroon Drive, Garfield County, Colorado
Dear Don and Dee:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on August 2, 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 December 31, 2019, Project No. 19-7-705.
At the time of our visit to the site, the foundation excavation had been cut in multiple levels from
4 to 11%2 feet below the adjacent ground surface. The soils exposed in the upper levels in the
northwest portion of the excavation consisted of very stiff sandy silty clay. The soils exposed in
the two deeper levels in the main portion of the excavation consisted of dense silty sandy gravel
with cobbles and boulders. No free water was encountered in the excavation and the soils were
dry to slightly moist. Footing forms and some steel reinforcing bars were in place at the time of
our site visit.
The 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 recommended allowable
bearing pressure of 1,500 psf on the undisturbed natural fine-grained soils and 3,000 psf on the
natural dense gravel soils. Any loose and disturbed soils should be removed in the footing areas
to expose the undisturbed natural soils prior to the placement of concrete. 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 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
Don and Dee Moore
September 2, 2020
Page 2
(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,
David Noteboom, Staff Engine„
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Reviewed by:
Daniel E. Hardin, P.E.
cc: Evolve Structural — Sara Mickus (_