HomeMy WebLinkAboutObservation of Excavation 01.18.20231(+A 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 Employ*® rimed Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
January 18, 2023
SCIB, LLC
Attn: Luke Gosda
0115 Boomerang Road, Suite 5201B
Aspen, Colorado 81611
Luke. og sda(&sunriseco.com
Project No. 21-7-595.A
Subject: Observation of Excavation, Proposed Residence, Lot 284, Ironbridge, Blue Heron
Vista, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on January 17, 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 August 11, 2021, Project No. 21-7-595.
The proposed residence is similar to that described in our previous report and will be a 2-story
structure supported on a structural slab foundation imposing a maximum allowable bearing
pressure of 1,500 psf.
At the time of our visit to the site, the foundation excavation had been cut in 2 levels from about
1 to 4 feet below the adjacent ground surface. The northeast perimeter grade beam trench had
been stepped down about 3 feet where the ground slopes down to the adjacent MSE site wall and
micro -piles had been installed. The soils exposed in the bottom of the excavation mainly
consisted of gravelly sandy silt and clay fill. Results of in -place moisture -density tests indicated
at least 98% compaction in the central and western area and around 90% near the eastern stepped
down part. The excavation was around 10 feet away from the backside of the MSE wall. No
free water was encountered in the excavation and the soils were very moist from snow melt and
not frozen.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site and suitable for support of structural slab foundation designed for the recommended
allowable bearing pressure of 1,500 psf. The lower density soils in the eastern part appear
localized to along the step-down and the micro -piles will lessen potential impacts to the MSE
wall. Loose disturbed soils should be moisture adjusted to near optimum and compacted. The
soils should be protected from frost and precipitation inundation and concrete should not be
placed on frozen soils. 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
SCIB, LLC
January 18, 2023
Page 2
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 &
Steven L.
SLP/kac
Kumar & Associates, Inc. 9 Project No. 21-7-595.A