HomeMy WebLinkAboutObservation of Excavation 10.25.2022
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 25, 2022
Scott Rosette
1998 Odin Drive
Silt, Colorado 81652
dottrosette@outlook.com
Project No. 22-7-688
Subject: Observation of Pit Excavations, Proposed Metal Storage Building, 1998 Odin
Drive, Lot 41, Asgard Subdivision, Third Filing, Silt, Colorado
Dear Scott:
As requested, a representative of Kumar & Associates observed the pit excavations at the subject
site on October 14, 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 October 14, 2022.
The proposed steel frame, metal skin, 40’ by 80’ storage building will have a slab-on-grade floor.
Foundations were designed for an allowable soil bearing pressure of 1,500 psf. The lot slopes
down to the southeast.
At the time of our visit to the site, we observed two pit excavations that had been excavated on
the lot near the southwest (Pit 1) and northeast (Pit 2) part of the lot. The soil exposed in the
pits, below about 1 foot of topsoil, consisted of silty sand and gravel down to the bottom of the
pits at 6 to 7 feet deep. The results of a gradation analysis performed on a sample of the silty
sand and gravel (minus 3-inch fraction) obtained from Pit 1 at about 4 feet deep are presented on
Figure 1. No free water was encountered in the pit excavations and the soils were slightly moist.
Considering the conditions exposed in the pit excavations 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 can be used for support of the proposed storage building.
Footings should be a minimum width of 16 inches for continuous walls and 2 feet for columns.
Loose and disturbed soils (and any topsoil) in footing areas should be removed and the bearing
level extended down to the undisturbed natural granular soils. The bearing soils should be
protected against frost and concrete should not be placed on frozen 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 45 pcf for on-site soil as backfill. A perimeter foundation drain
should be provided to prevent temporary buildup of hydrostatic pressure behind retaining walls
Kumar & Associates