HomeMy WebLinkAboutObservation of Excavation 04.12.2022'( � Kumar ni Associates, Inc.
Geotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
An Employee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
April 12, 2022
Brad Jennings
517 W. 13th Street
Glenwood Springs, Colorado 81601
brad. j ennings(&icloud.com
Project No. 21-7- 818
Subject: Observation of Excavation, Proposed Residence, Lot 32, Spring Ridge Reserve,
1255 Hidden Valley Drive, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on April 8, and 11, 2022 to evaluate the soils exposed for foundation support. The
findings of our observations 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 6, 2021, Project No. 21-7-818.
We understand the proposed residence has been designed to be founded on spread footings
bearing on the natural clay soils or bedrock and sized for an allowable bearing pressure of
1,200 psf.
At the time of our visit to the site on April 8, 2022, the foundation excavation had been cut in
2 levels from nil to 7 feet below the adjacent ground surface. The materials exposed in the
bottom of the excavation consisted of siltstone bedrock in the west part, slightly sandy clay in the
middle part, and topsoil in the east part. It was recommended that the topsoil be removed from
the footing areas and the bearing elevation be extended down to the relatively stiff, slightly sandy
clay soils.
At the time of our visit to the site on April 11, 2022, the foundation excavation had been cut in
multiple levels from 1 to 7 feet below the adjacent ground surface. The materials exposed in the
bottom of the excavation consisted of siltstone bedrock in the west part and slightly sandy clay
in the middle and east parts. No free water was encountered in the excavation and the soils were
slightly moist.
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 1,200 psf with a low risk of differential settlement. Loose and disturbed soils
and rock should be removed in the footing areas to expose the undisturbed natural soils or
bedrock. The bearing soils should be protected from frost and concrete should not be placed on
frozen soils. Other recommendations presented in our previous report which are applicable
should also be observed.
Brad Jennings
April 12, 2022
Page 2
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
(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,
Kumar & Associates, Inc.
Robert L. Duran, P.
Rev. by: SLP
RLD/kac
cc: Levi Troyer (lctroyerAmsn.com)
Kumar & Associates, Inc.'a Project No. 21-7-818