Valley R Center-CS 890919COMM. NO.:
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URBAN ARCHITECTURE--DALLAS
BY:
URBAN ARCHITECTURE--DALLaS 7001 PRESTON RD. SUITE 210 L.B. 12 DALLAS, TEXAS 7S205 (214) 522-8494
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EXPANSION JOINT
VALLEY RANCH CENTRE
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UAD #84437
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URBAN ARCHITECTURE--DALLAS 7001 PRESTON RD. SUITE 210 L.B. 12 DALLAS, TEXAS 75205 [214) 522-B494
It is recommended that the existing clay soils in drive and
parking areas be excavated to achieve final subgrade elevation.
The exposed surface of the clays should be scarified to a depth
of at least 6 inches and mixed with an estimated 5 to 7 percent
of hydrated lime (by dry unit weight) in conformance with Texas
Highway Department Item 260. The actual amount of lime required
should be determined by additional laboratory tests. Results of
a lime series reported by Southwestern Laboratories indicate
that 6 percent of hydrated lime will be required at this site.
The soil-lime mixture should 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. In all areas
where hydrated lime is used to stabilize the subgrade soils,
routine Atterberg-limit tests should be performed to assure that
the resulting plasticity index of the soil-lime mixture is at or
below 15.
Texas
this
soils
Triaxial Classification tests have not been performed for
specific project, but our previous experience with similar
indicates that the Texas Triaxial value for lime
stabilized clay will be about 1.0. The Texas Triaxial value for
the natural untreated clay will be about 6.0. Using the above
values, and assuming normal traffic for a 15-year project life,
we provide the following pavement recommendations for the
parking and drive areas. An asphaltic concrete pavement section
constructed upon a lime stabilized subgrade could consist of at
least 5.0 inches of asphaltic concrete, composed of 3.5 inches
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of binder under 1.5 inches of surface course in light duty
(automobile) traffic areas. In areas where heavy truck traffic
is expected, 6 inches of asphaltic concrete (4.5 inches of
binder and 1.5 inches of surface course) should be adequate.
the light
cover for
required.
In the event concrete pavements are used, the above recommended
procedure for mechanical lime stabilization would also be
required due to the highly plastic soils encountered near the
surface and the fact that the pavements are subject to flooding.
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
traffic area, however, to provide adequate concrete
the reinforcing steel, a 5 inch pavement section is
All concrete for pavements should have. a 28-day
design strength of at least 3,000 psi.
The calculations used to determine the required pavement
thickness are based on only 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 constructed
drawings and specifications.
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