HomeMy WebLinkAboutObservation of Excavation 10.28.2022Ilk—Kumar
� ni Al and Associates, Inc.lnc.
Geotechnicaand 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 Employe® Owned Company www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
October 28, 2022
Steve Nilsson
787 Canyon Creek Drive
Glenwood Springs, Colorado 81601
ssnkgLysford.com
Project No. 22-7-291
Subject: Observation of Excavation, Proposed Residence, Lot 2, River View Ranch,
167 Shore Drive, Garfield County, Colorado
Steve:
As requested by Alan Short, a representative of Kumar & Associates, Inc. observed the
excavation at the subject site on October 27, 2022 to evaluate the soils exposed for foundation
support. The findings of our observations and recommendations for the foundation design are
presented in this report. We previously conducted a subsoil study for design of foundations at
the site and presented our findings in a report dated June 9, 2022, Project No. 22-7-291.
The proposed residence is essentially the same as described in our previous report except that it
has been shifted around 30 feet to the south off of the steep downslope to the river. Spread
footings placed on the natural soils and sized for an allowable bearing pressure of 1,500 psf have
been designed for the foundation support.
At the time of our visit to the site, the foundation excavation had been cut in multiple levels from
2 to 5 feet below the adjacent ground surface and footing forms and steel reinforcement had been
placed. The soils exposed in the bottom of the excavation consisted of sandy silt and sandy silty
clay. No free water was encountered in the excavation and the soil moistures ranged from
slightly moist to very moist from recent precipitation including about 2 inches of snow.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site and suitable for support of spread footings designed for the recommended allowable
bearing pressure of 1,500 psf with the settlement risk from subsurface wetting the bearing soils.
Loose disturbed soils should be removed in the footing areas. Since the bearing soils have been
wetted, it is preferable to compact the subgrade when it dries to near optimum then reset the steel
reinforcement. The bearing soils should be protected from frost and concrete should not be
placed on frozen soils. Other recommendations presented in our previous report which are
applicable should also be observed.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and the previous subsurface exploration at the site. Variations
in the subsurface conditions below the excavation could increase the risk of foundation
movement. We should be advised of any variations encountered in the excavation conditions for
Steve Nilsson
October 28, 2022
Page 2
possible changes to 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,
Kumar & Associates, Inc.
Steven L. Pawlak, P
SLP/kac
cc: Alan Short
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Kumar & Associates, Inc.:; Project No. 22-7-291