HomeMy WebLinkAboutObservation of Excavation 05.07.2019K±A
Kaffir & I F „Inc.°
Geotechnical and Materials Engineers
and Environmental Scientists
An Employee Owned Company
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
May 7, 2019
Flores Construction
Attn: Larry Flores
3694 Valley View Road
Glenwood Springs; Colorado 81601
foresconstruction(a comcast.net
Subject:
Gentlemen:
10%1 AunNn
33Permix,
ui
1989-201
89 2 I
Project No. 18-7-451
Observation of Excavation, Proposed Residence, Lot 34, Spring Ridge Reserve,
Hidden Valley Drive, Garfield County, Colorado
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on May 3, 2019 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 August 31, 2018, Project No. 18-7-451.
The proposed residence is similar to that described in our previous report and will have slab -on -
grade floors. Spread footings placed on the natural soils and sized for an allowable bearing
pressure of 1,200 psf were designed for the foundation support.
At the time of our visit to the site, the building site had been leveled by cut into the hillside with
a retaining wall west of the building footprint. A perimeter footing trench excavation had been
cut in one level up to 4 feet below the adjacent ground surface. The northeast corner had
minimal cut depth to strip the topsoil. The soils exposed in the bottom of the excavation mainly
consisted of red -brown sandy silt and clay. Dark brown, slightly porous silt and clay was
exposed in the northeast corner area and should be cut down about 1 to 2 feet. No free water was
encountered in the excavation and the soils were slightly moist to moist.
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 1,200 psf. The dark brown silt and clay in the northeast corner and loose
disturbed soils in the footing areas should be removed to expose the undisturbed natural soils and
then moistened and compacted. 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
Flores Construction
May 7, 2019
Page 2
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
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
Kumar & Associates, Inc. Project No. 18.7-451