HomeMy WebLinkAboutObservation of Excavation 9.22.2022I(+AGeotechnical 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 Employee CWned Compony www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
September 22, 2022
Lynda Cameron
c/o Trevor Mountjoy
725 Spring Park Ridge Road
Carbondale, Colorado 81623
trevor.mountj oy(u,eaglesriseinvestments. com
Project No. 22-7-644
Subject: Observation of Excavation, Proposed Steel Barn, 725 Spring Park Ridge Road,
Garfield County, Colorado
Dear Ms. Cameron:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on September 20, 2022, 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 you dated September 20, 2022.
The proposed barn will be a tall, one-story, steel frame structure with a slab -on -grade floor.
Foundations were designed based on an assumed allowable soil bearing pressure of 3,000 psf.
At the time of our visit to the site, the foundation excavation had been cut in one level up to
6 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of stiff, sandy silty clay. No free water was encountered in the excavation and the soils
were slightly moist.
Considering the conditions exposed in the excavation and the nature of the proposed
construction, spread footings placed on the undisturbed natural soil designed for an allowable
soil bearing pressure of 3,000 psf can be used for support of the proposed barn. The exposed
soils tend to expand when wetted and there could be some post -construction movement
/settlement of the foundation if the bearing soils become wet. Footings should be a minimum
width of 16 inches for continuous walls and 2 feet for columns. Loose and disturbed soils (and
existing fill) in footing areas should be removed and the bearing level extended down to the
undisturbed natural soils. 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 50 pcf for on-site soil
as backfill. A perimeter foundation drain should be provided to prevent temporary buildup of
hydrostatic pressure behind retaining walls. Structural fill placed within floor slab areas can
consist of the on-site soils compacted to at least 95% of standard Proctor density at a moisture
content at about 2% over optimum. Backfill placed around the structure should be compacted
Lynda Cameron
September 22, 2022
Page 2
and the surface graded to prevent ponding within at least 10 feet of the building. Landscape that
requires regular heavy irrigation, such as sod, and sprinkler heads should not be located within
10 feet of the foundation.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation 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
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,
Itun1
Daniel
DEM
Kumar & Associates, Inc. " Project No. 22-7-644