HomeMy WebLinkAboutObservation of Excavation 06.19.24I n'A fliffi1fi#f*:ffiH'""ril'
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An Employcc Orncd Compony
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
hne 19,2024
Tally Ho Construction
Attn: Jeff Parrington
111 W. 3'd Street
Rifle, Colorado 81650
j eff@tallyhoconstruction. com
Subject:
Project No.24-7-134
Observation of Excavation, Proposed Building Two,6763 Highway 82,
Glenwood Springs, Colorado
Dear Jeff:
As requested, a representative of Kumar & Associates observed the excavation at the subject site
on June 6,2024, 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 Tally Ho Construction dated January 30,2024.
The proposed building will be one level steel frame structure with a slab-on-grade floor,
approximately 60' by 100'.
At the time of our visit to the site, the foundation excavation had been cut in three levels from
Iy2to 6 feet below the adjacent ground surface. The soils exposed in the bottom of the
excavation consisted of silty sandy gravel with cobbles. The results of a gradation analysis
performed on a sample from the site (minus I-Il2 inch fraction) obtained from the site are
presented on Figure 1. No free water was encountered in the excavation and the soils were
slightly moist to 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 2,000 psf should be adequate for support of the proposed building. 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 16 inches for continuous walls and2 feet for columns. Loose and disturbed soils in
footing areas should be removed and the bearing level extended down to the undisturbed natural
soils. Exterior footings should be provided with adequate soil cover above their bearing
Tally Ho
June 19,2024
Page2
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 should also be designed to resist alateral earth
pressure based on an equivalent fluid unit weight of at least 50 pcf for on-site soil as backfill.
Structural fill placed within floor slab areas can consist of the on-site soils compacted to at least
95% of standard Proctor density at a moisture content near optimum. Backfill placed around the
structure should be compacted and the surface graded to prevent ponding within at least 10 feet
of the building.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and do not include subsurface exploration to evaluate the
subsurface conditions within the loaded depth of foundation influence. This study is based on
the assumption that soils beneath the footings have equal or better support than those exposed.
The risk of foundation movement may be greater than indicated in this report because of possible
variations in the subsurface conditions. In order to reveal the nafure and extent of variations in
the subsurface conditions below the excavation, drilling would be required. It is possible the
data obtained by subsurface exploration could change the 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 funher assistance, please call our office
Sincerely,
Kumar & Associates, lnc
Daniel E. Hardin, P.E.
DEHlkac
cc Ridge Runner Construction - Brent Lough blridgerunner@,email.com
a
Kumar & Associates, lnc. @ Project No. 257-134
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SIEVE ANALYSISHYDROMETER ANALYSIS
U.S. SANDARO SERIESIITE RruIXCS
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DIAMET F PARTICLES IN
CLAY TO SILT COBBLES
GRAVEL 31 %
LIQUID LIMIT
SAMPLE OF: -
SAND 39 %
PLASTICIW INDEX
SILT ANO CLAY 30 %
FROM: -
Th..c 16rl r.tulh opply only lo lh.
rompl.! whloh w.ro l.!i.d. Th.
l.tllng raporl.holl nol ba r.prcduoad,
.xc.pl ln full, vllhoul th. wrlil.n
qpprcvol of Kumor & Artoclola!, lnc.
sl.v. onolytir l.rllng It p.rformtd In
occordonc. vlth Asttl 069.13, ASIM 07928,
ASTI clJ6 ond,/or ASTM Dll,to'
GRAVELSAND
COARSEFINEMEDIUM ICOARSE FINE
24-7 -134 Kumar & Associates GRADATION TEST RESULTS Fig. 1