Food Lion-LR 900829GEOTECHNICAL INVESTIGATION
for
Food Lion, Store No. 6A
Sandy Lake @ Samuel Blvd.
Coppell, Texas
ALPHA REPORT NO. 90238
ALPHA TESTING, INC.
An 4;cnc Services Gicuo ComPCTIY
22Cy Nsccnsrn St. Suite TC0
-c!res "excs 15229
2'- %_ZC -8
AAX 2 ?414C64023
August 29, 1990
Artech Design Group
1303 Walnut Hill Lane, Suite 130
Irving, Texas 75038
Attention: Mr. Rory Chen, AIA
Re: Geotechnical Investigation
Food Lion, Store No. 6A
Sandy Lake @ Samuel Blvd.
Coppell, Texas
ALPHA Report No. 90238
Gentlemen:
Submitted herewith is the report of our geotechnical investigation
at the site of the referenced project. This study was authorized
by Mr. Rory Chen, AIA, in accordance with our proposal agreement
dated August 21, 1990.
This report contains the results of our findings, an engineering
interpretation of these with respect to the available project
characteristics and recommendations to aid desicn and construction
of foundations and other earth connected phases of this project.
We appreciate the opportunity to be of service to you on this
project. If we can be of further assistance, such as providing
our materials testing services during construction, please contact
our office.
Very truly yours,
w
I L I
: ALPHA EST ING, IIN C .
vid A. Lewis, P.E.
Manager of Engineering Services
Jim L. Hillhouse, P.E.
President
Copies: (4) Client
Alpha Report No. 90238
Although movements are estimated to be within tolerable limits
for structural safety, such movements could be detrimental to
the slab if it were rigidly connected.-to the foundation.
Floor slabs which are dowelled into the perimeter grade beam
typically develop a plastic hinge (crack) -.parallel to and
approximately five to ten ft inside of the building perimeter.
The plastic hinge may be controlled by constructing a joint
in the floor slab in the area of the anticipated hinge
location.
There may be certain areas where it will be difficult or
impractical to make the slab floating. In such areas, it may
be necessary to increase the slab thickness and 'reinforcement
to prevent the foundations from cracking the slab and settling
independently. In addition, a moisture barrier of
polyethylene sheeting or similar material should be placed
between the slab and subgrade soils to retard moisture
migration through the slab.
6.4 Pavements
The sandy clay or clayey sand soils encountered near the
existing ground surface will probably constitute the subgrade
for most of the parking and drive areas. Therefore, it is
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Alpha Report No. 90238
recommended that these soils be improved prior to construction
of the pavements.
It is recommended that the existing sandy clay or clayey sand
soils in drive and parking areas be graded to achieve final
subgrade elevation. The exposed surface of the sandy clays
should be scarified to a depth of at least 6 inches and then
be compacted to at least 98 percent of Standard Proctor
maximum dry density (ASTM D 698) at /or slightly above the
optimum moisture content.
California Bearing Ratio (CBR) tests have not been performed
for this specific project, but our previous experience with
similar soils indicates that the CBR value for existing sandy
clay or clayey sand will be in the range of 8 to 10. Using
the above CBR value, and assuming normal traffic for a 15 —year
project life, we provide the following pavement design for
parking and drive areas provided traffic will consist of cars
and occasional light trucks. Pavements could then consist of
5 inches of adequately reinforced concrete in both light duty
and heavy truck traffic areas. Theoretically, a thinner
pavement section is possible in the light traffic area,
however, to provide adequate concrete cover for the
reinforcing steel, a 5 inch pavement section is required.
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Alpha Report No. 90238
The calculations used to determine the required pavement
thickness are based only on the physical and engineering
properties of the materials and conventional thickness
determination procedures. Related civil design factors such
as subgrade drainage, shoulder support, cross - sectional
configurations, surface elevations, reinforcing steel, joint
design and environmental factors will significantly affect the
service life and must be included in the preparation of the
construction drawings and specifications.
6.5 Pavement Specifications
Pavements should be specified, constructed and tested to meet
the following requirements:
1. Portland Cement Concrete - Texas SDHPT Item 360.
Specify a minimum compressive strength of 3,000 lbs.
per sq inch.
2. Recompacted Subgrade - on -site sandy clay and /clayey
sand materials should be scarified to a depth of 6
inches and recompacted to at least 98 pet.:cent of
ASTM 698 at /or slightly above the optimum moisture.
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