HomeMy WebLinkAboutSoil Test{" t't"t"'.-' lr)vvVslr,y
5020 County Road 154
0lenwood $prirrgs, CO 81001
Plrur¡s: (970) g45"79BB
Fax (970) 945-8454
Ëmail: hpkglenwood@kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwoorl Springs, Summit Gounty, Colorado
April4, 20i8
{iregg Hollomon
7?1 County Road 112
Carbondale, Colorado 81623
gregghol lQmon@ ]¡ahoo.com
Project No. 18-7-241
Snbject: ûbsenation of Exsavation, Proposed GaragelShop,TTl County Road 1i2,
Garfield County, Coiorado
Dear Mr. Hollomon:
As requesled, the undersigned representalive of H-PlKumar observed tlre excavation at the
subject site on April 3,2018, to evaluate the soils exposed for foundation support. The findings
of our observations and recorñmendations for the foundation design are presented in this report.
The services were performed in acc*rdance with our agreenrent for professional engineering
services to you, dated April 2,2018.
The proposed garcge will be a one story Morton Building, steel frame, metal skin with a slab-on-
grade floor. Foundations were designed for an assumed allowable soil bearing pressure of 2,000
psf.
'4't the time of our visit to the site, the foundation excavation had been cut in two levels from 3 to
6 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of basalt cobbles and boulders in a calcareous, gravelly, sandy silt matrix. Undisturbed
sampiing of the matrix soils was not possible due to the rock contcnt. No free water was
encountered in the excavation and the soils were slightly moist. The excavation surface soils had
been loosened during excavati<¡n and probing ofthe subgrade revealed that there werc pockets of
loose soil up to 10 inches deep from rock removal. We rscommendecl to Jack Palomino, general
contractor at the site, to either remove the loose soils or mcisten and compact the footing and
slab subgrade. The loosened soils should be compacted to at Least gSVa of the maximum
standald Proctor density at a moisture content near optimum.
H-PVKUIVIAR
Gsotcchnical Fnginacrirrg | Ërrgírreerirrg Geology
Materials Testing I Environrnental
Ø
Gregg Holloman
April4, 2018
PageZ
Considering the conditions exposecl in the excavatian and the nature of the proposed
construction, spread footings placed on the undistulbed natural soil ciesigned for an allowable
soil bearing plessure of 2,00û psf can be used for support of the proposed garage. The exposed
matrix soils tend to compress when wetted and there could be some pûst-construction settlement
of the fr:undation if the bearing soils become wet. Footings shculii be a minimum width of 1ó
inches for continuous walls and 2 feeL fr¡r columns. Lerose and disturbed soils in footing areas
should be remaved or maistened and cornpacted as recomrnended above. Tihe bearing soils
should be pr:otected against frost and concrete should nût be placed on frozen soils. Exterior
footings should be provided with adequate soil cover above their bearing elevations for frast
protection. Continuous foundation walls should be reinforced top and bottom to span lccal
anomalies such as by assuming an unsupported length of at least 12 feet. Foundation walls
acting as retaining structures should also be designed to resist alateral earth prcssure based on an
equivalent fluid unit weight of àt least 50 pcf for on-site sc;il as backfill exclueling rock larger
than 6 inches. A perimeter foundation drain should be provided to prevent temporary builelup of
hyclrostatic pressure behind the fô¡"¡ndation retaining walls. Structural fill placed within floor
slab areas can consist of the on-site soils or a suitable imported gravel such as 3/q inch road base
or screened rock compacted to at least 957o of standard P¡octor density at a moisture content near
optinllrm. Backfili placed around the.structure should be compacted and the surface graded to
prevsnt ponding within at least 10 feet of the building.
The rec*mmendations submitted in this letter arc basecl on our observation of the soils exposed
within the founclation excavation and do n<¡t include subsurface explolation to evaluate the
subsurface conditions within the laaded depth of faundation influence. This study is based on
fhe assumption tbat soils beneath the footings have equal cr better suppofi 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 îo reveal the nature and extent ofvariations in
the subsurface conditions below the excavation, drilling wouid be required. It is possible the
data obtained by subsurface exploration could change the recommendaTions contained in this
letter. Our services do nc,t include determining the presence, prevention or possibility nf mold cr
H-P!KUMAR
Project No. 18-7-241
Gregg Holloman
April4, 2018
Page 3
athel biological contaminants (MOBC) developiug in the future. If the client is concerned about
MOBC, then a professir:nal in this special field r:f pracfice should be consulted.
If you have any questions or need further assistance, please call our office.
$incerely,
}.I-F* KUM,A,R
<.,rþ ç".
",a:
Daniel E. Hardin, P *4q{q {k a':
R.ev. By: SLP
DEI{/kac
t/t-.Jack Palomino ieqhpalomino5å9 g$ail.coni
H.PVKUMAR
Projec't No. 18-7-241