HomeMy WebLinkAboutBLDR-6-11-19353ENGSOILEVALUATION.tif August 10, 2011
Mr. Curtis Barlowe
Barlowe Brothers, LLC email: barlowc @bellsouth.net
PO Box 2866
Hickory, North Carolina 28603
RE: Report of Foundation Soil Evaluation
835 32 nd Ave. Dr. NW
Hickory, NC 28601
Permit #6 -11 -19353
Unifour Job Number 3691
Dear Mr. Barlowe:
As you requested, Unifour Engineering & Testing Laboratories, PC ( Unifour) was
retained to test and observe the shallow foundation soil for 835 32 Ave. Dr. NW,
located in Hickory, North Carolina. Unifour's scope did not include investigation of
deep subsurface conditions or the development of engineering recommendations for
foundation design.
Dynamic Cone Penetrometer (DCP) tests were performed in the soil within the
foundation footprint of the proposed structure at the bottom of footing elevation (BOF)
and as deep as 3 feet below BOF. The DCP test is performed by driving a 1
diameter steel cone into the soil using a 15 -pound weight falling 20 inches. The
number of blows required to drive the cone 13/4 inches is designated as the Cone
Penetrometer Resistance and is recorded in units of 'blows per increment' or bpi. The
test procedure is described in ASTM Special Technical Publication STP -399. The
DCP test values were correlated to an estimated Standard Penetration Resistance (N-
value) based on the soil type, using procedures described in STP -399. The field data
and estimated N- values are presented in the attached Report of Dynamic Cone
Penetrometer Test forms.
The foundation soil encountered at and below the BOF at the test locations consisted
predominately of silty sand. The estimated N- values indicated in the DCP tests were
generally greater than 7 blows per foot (bpf). However, loose soils were encountered
at the BOF along the north and east footing lines.
MU nifour
4kac,. \C_M,i ._� ,.�:E �. Engineering & Testing Laboratories, PC
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Foundation Soil Evaluation -3691
°d August 10, 2011
835 32 Ave. Dr. NW, Hickory, NC Page 2
According to information provided by you, the foundation design and footing widths for
this structure are based on an allowable soil bearing pressure of 2,000 pounds per
square foot. Due to encounter of loose soils along the north and east footing lines,
Unifour recommended modifying the excavation limits in this area. Unifour
recommended undercutting the north footing line to a depth of 1 foot below BOF to
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remove loose soil and widening the footing line to a total width of 30 inches. As an
alternative to undercutting the footing line in the loose soil area you may elect to
widen the footing line to a total width of 36 inches at the current BOF, followed by
mechanically tamping and compacting the exposed soils prior to concrete
placement. The footing modifications should extend across the full length of both
the north and east exterior wall lines. The modified footings should also contain 3
continuous pieces of #4(minimum) rebar that should extend an additional 10 feet
laterally beyond the limits of the modified footings.
r Please note that inclement weather conditions can affect the current soil conditions
and the soil's bearing pressure. Unifour should be requested to re- evaluate the
foundation soil conditions if inclement weather is encountered prior to the placement
of footing concrete.
E
Since bearing capacity of soil is partly a function of soil type and footing width, these
test results should be considered valid only for the locations and elevations noted at
the time of our testing.
We appreciate the opportunity to be of service to you on this phase of the project. If
we can provide any additional engineering or testing services please contact us.
Respectfully submitted, 00 %0 11 11 , ,,,. 1
UNIFOUR ENGINEERING & TESTING LABORATORIES �.f�1�k - Cri,q()
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Matthew D. Hartl , El �Y Bobby L. Barnes, PE
Project Engineer Principal Engineer
Registered, NC 019385
Date:
Attachments: Report of DCP Test 08 -10 -11
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