HomeMy WebLinkAboutObservation of Excavation 09.19.2023Kunw & Assoc1nte% km.
'( 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
September 19, 2023
SCIB, LLC
Attn: Luke Gosda
0115 Boomerang Road, Suite 5201B
Aspen, Colorado 81611
Luke. og sda(a)sunriseco.com
Project No. 20-7-785
Subject: Observation of Excavation, Proposed Residence, Lot 38, Ironbridge Phase 3,
Blue Heron Drive, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on September 14, 2023 to evaluate the soils exposed for foundation support. The findings of our
observations and recommendations for the foundation support are presented in this report. We
previously performed a subsoil study for foundation design at this site, report dated February 22,
2021, and a basement addendum report dated September 11, 2023, Project No. 20-7-785.
The proposed construction is similar to that discussed in our previous report with the addition of
a walkout lower level. The building has been designed to be supported on spread footings using
an allowable soil bearing pressure of 1,500 psf as recommended.
At the time of our visit to the site, the foundation excavation had been cut in 3 levels from 2'/2 to
9 feet below the adjacent ground surface. The grade steps were about 2'/2 to 6%2 feet between
levels. The soils exposed in the bottom of the excavation consisted of stiff, sandy silty clay in
the upper level and relatively dense, silty sandy gravel with cobbles in the lower level. 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 1,500 psf. Loose and disturbed soils should be removed in the footing areas
to expose the undisturbed natural soils. Other recommendations presented in our previous report
which are applicable, especially those to keep the clay bearing soils dry, 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
(MOBC) developing in the future. If the client is concerned about MOBC, then a professional in
this special field of practice should be consulted.
SCIB, LLC
September 19, 2023
Page 2
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, Inc ^o�O RE
n 15222 5,;
Steven L. Pawlak, P.E.
SLP/kac ��SS/cpNAl EN��
Kumar & Associates, Inc. 0 Project No. 20.7.785