HomeMy WebLinkAboutObservation of Excavation 11.16.23
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
November 16, 2023
Chelsea Tesky
208 Heather Lane
Glenwood Springs, Colorado 81601
chelseatesky@gmail.com
Project No. 23-7-607
Subject: Observation of Excavation, Proposed Residence, Lot 4, Gilead Gardens,
57 Garden Circle, New Castle, Colorado 81647
Dear Chelsea:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on November 13, 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 you dated October 19, 2023. A preliminary geotechnical study for this subdivision was
performed by Hepworth-Pawlak Geotechnical and presented in a report dated December 29,
2000 Job No. 100 672.
We understand the proposed residence has been designed to be founded on spread footings
bearing on the natural soils and sized for an allowable bearing pressure of 1,500 psf.
At the time of our visit to the site, the foundation excavation was essentially complete and had
been cut in one level 6 feet below the adjacent ground surface. The soils exposed in the bottom
of the excavation consisted of stiff sandy silt with scattered gravel. Results of swell-
consolidation testing performed on a sample taken from the site, shown on Figure 1, indicate the
soils are moderately compressible under conditions of loading and wetting with a low hydro-
compression potential when wetted under a constant light load. 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 1,500 psf can be used for support of the proposed residence with a risk
of settlement. The exposed soils tend to compress when wetted and there could be some post-
construction settlement of the foundation if the bearing soils become wet. Footings should be a
minimum width of 18 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. The exposed soils in footing areas should then be moistened and compacted. 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
Kumar & Associates