HomeMy WebLinkAboutObservation of ExcavationK+A Geotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
Z, email: kaglenwood@kumarusa.com
An EMP10yee Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
June 21, 2023
Giard Homes
Attn: Roger Giard
roger ig ard(&giardhomes.com
Project No. 19-7-220.A
Subject: Observation of Building Pad, Proposed Residence, Lot 252, Ironbridge,
Garfield County, Colorado
Dear Roger:
As requested, a representative of Kumar & Associates observed the existing building pad and
performed density testing at the subject site on June 20, 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. The services were performed in accordance with our
agreement for professional engineering services to Giard Homes dated June 20, 2023.
At the time of our visit to the site, the building pad was in one level. The soils exposed in the
pad consisted of silty sandy gravel. Density testing was performed and indicated in -place
densities of 123.6 pcf to 125.0 pcf at moisture contents of 9.9% to 10.6%. Overall, the soils
appeared to be dense and moist. Based on our experience, we estimate that the soils were
compacted to about 98% of the maximum standard Proctor density.
Considering the conditions exposed at the site and the nature of the proposed construction,
spread footings and slabs placed on the exposed compacted soil should be suitable for support of
the proposed residence. Footings should be a minimum width of 16 inches for continuous walls
and 2 feet for columns. Loose and disturbed soils in footing areas should be removed or re -
compacted prior to placing concrete. Exterior footings should be provided with adequate soil
cover above their bearing elevations for frost protection. Continuous foundation walls should be
reinforced top and bottom to span local anomalies such as by assuming an unsupported length of
at least 10 feet. Foundation walls acting as retaining structures (if any) should also be designed
to resist a lateral earth pressure based on an equivalent fluid unit weight of at least 45 pcf for on -
site soil as backfill. Backfill placed around the structure should be compacted and the surface
graded to prevent ponding within at least 10 feet of the building.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation footprint and do not include subsurface exploration to evaluate the
subsurface conditions within the loaded depth of foundation influence. This study is based on
the assumption that soils beneath the footings have equal or better support than those exposed.
The risk of foundation movement may be greater than indicated in this report because of possible
variations in the subsurface conditions. In order to reveal the nature and extent of variations in
the subsurface conditions below the excavation, drilling would be required. It is possible the
data obtained by subsurface exploration could change the recommendations contained in this
Giard Homes
June 21, 2023
Page 2
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 & As
Daniel E. Hardin,
DEH/kac
Kumar & Associates, Inc. R Project No.19-7-220.A