HomeMy WebLinkAboutObservation of Excavation 11.17.2022
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
November 17, 2022
Revised December 5, 2022
Russell Cartwright
35 Willowview Way
Parachute, Colorado 81635
russecart@gmail.com Project No. 22-7-523.A
Subject: Observation of Excavation, Proposed Residence, Lot 6, Block 3, Section 2,
Battlement Creek Village, 47 Valley View Place, Garfield County, Colorado
Dear Russell:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on October 26, 2022 to evaluate the soils exposed for foundation support. We then subsequently
performed compaction testing on the structural fill placed below the footing areas. The findings
of our observations and recommendations are presented in this report. The services are
supplemental to our agreement for professional engineering services to you dated July 25, 2022.
We previously conducted a subsoil study for design of foundations at the site and presented
our findings in a report dated September 27, 2022, Project No. 22-7-523.A. The proposed
construction is similar to that discussed in our previous report. The building has been designed
to be supported on spread footings bearing on structural fill and sized for an allowable soil
bearing pressure of 1,500 psf with, as recommended with some risk of settlement.
At the time of our October 26 site visit, the foundation excavation had been cut in one level from
about 1 to 6 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of stiff to very stiff, sandy clayey silt. Results of swell-consolidation
testing performed on samples 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. No groundwater was encountered in the excavation and the soils were slightly moist.
We subsequently observed the scarifying, moistening and compacting of the subgrade soils and
then the placement and compaction of the 2 feet of on-site soils placed as structural fill below the
footing areas on a part-time basis. Based on our test results, the structural fill was compacted to
at least 98% standard Proctor density as recommended. The results of our laboratory Proctor and
compaction testing on the structural fill will be provided under separate cover.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site and the structural fill adequately compacted, and suitable for support of spread
footings designed for the recommended allowable bearing pressure of 1,500 psf. The risk of
foundation settlement is if the bearing soils below the structural fill were to become wetted and
precautions should be taken to prevent wetting. Prior to the footing construction, any loose
disturbed soils should be removed or the subgrade re-compacted as needed. The bearing soils
Kumar & Associates