HomeMy WebLinkAboutObservation of Excavation 09.04.2018H-PVKUMAR
Geotechnlcâl Engìneerlng I EnglneErlng Geology
Materials Testing I Envlronmental
5020 County Road 154
Glenwood Springs, C0 91601
Phone: (970) 945-7988
Fax (970) 94s-84S4
Email: hpkglenwood@kumarusa.com
Office Locations:Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, Summit County, Colorado
September 4,2018
Divide Creek Builders
Attn: Max Filiss
1531 County Road 342
Silt, Colorado 81652
max @dividecreekbuilders.com
Project No. 18-7-249
Subject:Observation of Excavation, Proposed Foster Barn, Aspen Valley Polo Club,
164ll Old Highway 82, Garfield County, Colorado
Gentlemen
As requested by Chris Calalrro, a representative of H-P/Kumar observed the excavation at the
subject site on August 30, 2018 to evaluate the soils exposed fol foundation support. The
findings of our observations and recommendations for the foundation design are presented in this
report. The services were performed in general accordance with our agrcement for professional
engineering services to Divide Creek Builders, dated April 4,2018.
The Foster barn (barn #3) has been designed to be supported on shallolv spread footings sized for
an allowable bearing pressure of 1,500 psf.
At the time of our visit to the site, the foundation excavation had been cut in 2 levels frcm r/z to
2 feet below the adjacent ground surface. The perimeter footing trcnch was typically 2 feet deep
arid the interior footing pad excavations were between Yz to 2 feet deep. The soils exposed in the
bottom of the excavation consisted of relatively dense, silty sandy gravel with cobbles. The
results of a gradation analysis performed on a sample of the gravel (nr,inus 3-inch fraction)
obtainecl from the site are presented on Figure L No fi'ee water was encountered in the
excavation and the soils rvere slightly moist.
Considering the conclitions exposed in the excavation arid the nature of the proposed
construction, spread footings placed on the undisturbed natural gravel soil designed for an
allowable soil bearing pressure of 1,500 psf shoul.d be adeqr-rate for support of the proposed barn.
The exposed soils are relatively dense ancl post-construction settlement should be relatively
minor. Footings should be a minimurn width of 16 inches for continuous walls and 2 feet for
columns. Loose disturbed soils in footing areas should be removed or moistened and compacted.
Exterior footings should be provided with adequate soil çover above their bearing elevations for
frost protection. Continuous foundation walls shor"rld be reinforced top and bottom to span local
Divide Creek Builders
September 4,2018
Page2
anomalies such as by assuming an unsupported length of at least 10 feet. Structural fill placed
within floor slab areas can consist of the on-site gravel soils (excluding rock over 6 inches)
compacted to at least 95o/o of standard Proctor density at a moisture content near optimum.
Backfill placed around the structure should be compacted and the surface gradecl tCI prevent
ponding within at least 10 feet of the buiiding.
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 irave equai or better support than those exposed.
The risk of foundation movement may be greater than inclicatecl in this repofi because of possible
variations in the substtrface conditions. Ìn order to reveal the natnre and extent of variations in
the subsurface conclitions below the excavation, drilling would be required. It is possible the
datâ obtained by subsurface exploration could change the recomrnendations contained in this
letter' Our services do not include determining the prescncc, prcvention or possibility of ¡rolcl or
other biological contaminants (MOBC) cleveloping in the future, If the client is concerned about
MOBC, fhen a professional in this special field of practice shoulcl be consulted.
Tf yorr have any questions or neecl further aosistanco, please call our officc,i
Sincerely,
H.PT KUMAR
Steven L. Pawlak,
SLP/kac
Attachment: Figure 1-t Results
cc:Divide creek Builders - chris calabro (chri s g dividecreekbuilders.cop)
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H.PÈKUIVIAR
Project No. 18-7-249
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FINC MEOIUM FINE COÄRSE
1B-7 -249 H-PryKUMAR GRADATION TIST RESULTS Fig 1