HomeMy WebLinkAboutObservation of Excavation 07.24.20231(+AandK°� n` , �.-
Geotechnical and Materials Engineers 5020 County Road 154
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
July 24, 2023
SCIB, LLC
Attn: Luke Gosda
0115 Boomerang Road, Suite 5201B
Aspen, Colorado 81611
luke. og sda(&sunriseco.com
Project No. 21-7-434.A
Subject: Observation of Excavation, Proposed Residence, Lot 37, Ironbridge Phase 3,
Blue Heron Drive, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on July 20 and 24, 2023 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 June 25, 2021, Project No. 21-7-434.
The proposed residence is similar to that described in our previous report but has been modified
to include a walkout basement level. Spread footings placed on the compacted fill or natural
soils and sized for the recommended allowable bearing pressure of 1,500 psf have been designed
for the foundation support.
At the time of our initial visit to the site, the eastern foundation excavation area had been cut in
3 levels from 2 to 5 feet deep mainly exposing compacted fill at the upper level and sandy gravel
at the lower level. When observed on July 24, the excavation was complete and cut in multiple
levels from about 2 to 8 feet below the adjacent ground surface. The soils exposed in the bottom
of the excavation consisted of compacted fill at the upper level and sandy gravel at the middle to
lower levels. The results of in -place dry density testing on the upper fill of 116.1 pcf at 7.3%
moisture content indicate around 98% compaction. No free water was encountered in the
excavation and the soils were slightly moist to 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 disturbed soils in the footing areas should be moistened and
compacted. 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
SCIB, LLC
July 24, 2023
Page 2
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 & Assoc
Steven L. Pawl
SLP/kac
Kumar & Associates, Inc. 0 Project No. 21.7-434.A