HomeMy WebLinkAboutObservation of Excavation 10.12.2022Kumar & Associates, Inc.
Mt -11
Geotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
Z 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
October 12, 2022
SCIB, LLC
Attn: Luke Gosda
0115 Boomerang Road, Suite 5201B
Aspen, Colorado 81611
lake. og sda cr,sunriseco.com
Project No. 21-7-219.A
Subject: Observation of Excavation, Proposed Residence, Lot 285, Ironbridge, Blue Heron
Vista, Garfield County, Colorado
Gentlemen:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on September 30 and October 10, 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 April 13, 2021, Project No. 21-7-219.
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 1'/2 to
3 feet below the adjacent ground surface. The northeast perimeter grade beam trench had been
stepped down about 1 Meet where the ground slopes down to the adjacent MSE site wall. The
soils exposed in the bottom of the excavation mainly consisted of sandy silt and clay fill. Results
of in -place moisture -density tests indicated about 98% compaction in the western part and
around 92 to 94% in the eastern stepped down trench 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 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 structural slab foundation designed for the recommended
allowable bearing pressure of 1,500 psf. The lower density soils in the eastern part appear
localized and the foundation step-down on the east side lessens potential impacts to the MSE
wall. Loose disturbed soils should be moistened as needed 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
SCIB, LLC
October 12, 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. 6 Project No. 21-7-219.A