HomeMy WebLinkAboutRe: site visit/evaluate soils Jul 17 06 08: 32a p. l
� � = INSTANT TESTING COlVIPANY
71?5 West 12hth Street • Suice �OU • Savage, ivlN��37g 35th
� �� PHONE: 952-890-i366•FAX: 9�2-fi90-�883
\� ANN(VERSARY
. 2003
July 14, 2006
Mr . Mark Finney
3210 Korth Shore Drive
Orono , Minnesota 55391 Cell : 612-803-1720
RE: 3210 North Shore Drive
Orono , Hennepin County, Minnesota
As requested, a site visit was made July 14, 2006 at 9 : 45 A.M. to
evaluate subgrade soils tor construction of a detached garage at
a residential site.
�,t the time of the inspection, the garaqe footings were fully
exeavated to appropriate frost depth, with zooting forms in-place.
Witn the exception of a 12 ' section of che rear footyng line, the
footing base had been correctecl for over excavation, with
approximately 1 ' of a coarse i 1/2" clear aggregate.
To evaluate the subgrade soils , a 1 5/8" fluzed handauger probe was
put down near the mid-point of the front and rear footing lines .
The firs� handauger , cvnducted at the rear footing to a depth of 4
3/4 £eet , indicated zones of a moist lean clay, loamy sand & gravel ,
a dark organic clay at 1 1/4 feet , with a dark grey/green clayey sand
at depth. The strata of organic clay although primarily cohesive ,
contained a thin zone of clay loam with small root fibers and a
isolat�d pocket of peaty clay. This material had minimal organic
odar or fibrous content, with a organic content judged to be 6
percent or Iess .
The second probe was placed to 3 1/2 feet through the aggrega�e base
at the front footing, and indicated a strata of dark clayey
' sand underlain by a SP loamy sand . Subgrade soils at each -
probe location were firm, and capable of supporting full body weight
applied to the probe. Ground water was present at approximately 1
1/2 foot below the base, of the footing within the building pad.
The relative loadbearing capacity of the subgrade soils , was
determined by a dynamic cone penetrometer test conducted near the
mid-point of the rear footing line. The dynamic cone penetrometer
(DCP) , uses a eight kilogram (17 . 6 pound) hammer to drive a 20
millimeter diameter conical point into the soil , with he penetration
recorded in millimeters per blow. From the DCP readings , a per blow,
penetration average was recorded and a N-value derived. This N-
Jul 17 06 08: 32a p. 2
value, is an empirical relationship we have established to equate the
dynamic cone data to the more familiar blows per foot (BPF) standard
penetrat•ion soil boring test . �
Dynamic Cone Penetrometer Test
DCP Depth Per Blow Ava. / N-Value Estimated• Load
851 MM (33 . 5") 42 . 8 MM / N-7 : 3 2600 PSF
In our opinion, the observed and tested subgrade soils are
qenerally acceptable and would be expected to provide an assumed
bearing capacity requirement af 2000 P3F or less . We would
consider the footing design of 20" R 10" acceptable for the
proposed construction, but would recommend the addition of 2 - #5
reinforcement .rods . The reinforccment may be crossed at the corners,
with splices were required at a minimum 36 bar diameters . �
our observations and subsequent soil evaluation on this date are
Iimited in scope to soil conditions abserved within li.mited sections
of the footinq excavation and to depths achieved by shallow probes
and a dynamic cone penetrometer test. We therefore, are unable to
assess soil condi•;.ions at depths which may be encountered by soil
borinqs conducted as part of a standard subsurface geotechnical
investigation.
Sincerely,
Insta ' ng Company
� �
a y ta i Dennis Odens , P.E.
spector '
CC: City of Orono uildinq Inspections
, #701 - 1 / #605 1 1/4 / #304 - DCP {1) / #612 - 52
FINNEYMK.DOC