HomeMy WebLinkAboutObservation of Excavation 10.11.2023
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
www.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
October 11, 2023
Daly Capitol Builders
Attn: August Filiss
P.O. Box 324
Woody Creek, Colorado 81656
affwcc@yahoo.com
Project No. 23-7-490
Subject: Observation of Excavation, Proposed Steel Building, 9412 Highway 82, Garfield
County, Colorado
Dear August:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on October 3, 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 Daly Capitol Builders dated September 29, 2023.
The proposed steel building will be a single-story structure with a 20 by 100-foot footprint. The
building has been designed to be supported on spread footings sized for an allowable bearing
pressure of 1,500 psf.
At the time of our visit to the site, the foundation excavation had been cut in one level up to
2½ feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of medium dense, silty sand and gravel with subangular rock. The results of a
gradation analysis performed on a sample of sand and gravel (minus 1½-inch fraction) obtained
from the site are presented on Figure 1. No free water was encountered in the excavation and
the soils were slightly moist to 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 1,500 psf should be adequate for support of the proposed building.
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 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
well 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. A perimeter foundation drain should not be necessary for the
proposed slab-on-grade construction. Structural fill placed within floor slab areas can consist of
Kumar & Associates