HomeMy WebLinkAboutObservation of Excavation 08.10.2022K+Aand& Aswu1<1�,,�.Geotechnicai and Materials Engineers 5020 County Road 154
Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood(a&kumarusa.com
An Employee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
August 10, 2022
SCIB, LLC
Attn: Luke Gosda
0115 Boomerang Road, Suite 5201B
Aspen, Colorado 81611
Luke. osda()sunriseco.com
Project No. 21-7-304.A
Subject: Observation of Excavation, Proposed Residence and Garage, Lot 26, Ironbridge,
Phase III, River Bend Way, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on August 8, 2022 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 May 7, 2021, Project No. 21-7-304.
The residence will be above a basement and the garage will be detached in the uphill, south part
of the lot. Spread footings placed on dense gravel or compacted structural fill and sized for an
allowable bearing pressure of 2,500 psf were recommended for the foundation support.
At the time of our visit to the site, the foundation excavation for residence had essentially been
cut in one level from 5 to 6 feet below the adjacent ground surface. The soils exposed in the
bottom of the excavation consisted of dense, sandy gravel and cobbles. The garage excavation
consisted of cut and fill sections of around 1 to 2 feet to achieve the footing bearing level. the
fill material consisted of 3/-inch road base. Results of in -place density tests performed on the fill
material on August 9 (to be reported separately), indicated relative compaction of 98 to 99%. No
free water was encountered in the excavation and the soils were slightly moist.
The gravel soils exposed in the residence 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 2,500 psf. The garage soils are a combination of
natural clay and fill and an allowable bearing pressure of 1,500 psf should be adequate to support
footings with a minimum width of 20-inches and some settlement potential mainly if the bearing
soils are wetted. Loose disturbed soils in the footing areas should be removed to expose the
undisturbed natural soils or 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
SCIB, LLC
August 10, 2022
Page 2
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 &
Steven L.
SLP/kac
Kumar & Associates, Inc. Project No. 21-7-304.A