Gateway BP(1.2)-CS 960508BROCKE rTE' DAVIS' .DRAKE, inc.
consulting engineers
May 8, 1996
Mr. Ken Griffin, P.E.
City of Coppell
255 Parkway Blvd.
Coppell, Texas 75019
Fritz Warehouse
Alternate Pavement Design
Coppell, Texas
BDD Project No. C96046
Dear Mr. Griffin:
We respectfully request that an alternate pavement section be allowed for the above referenced project.
In lieu of lime stabilization, the pavement strength will be increased from 3500 psi to 4000 psi at 28 days
(7" in truck dock, 6" in drive lanes, 5" in passenger car parking area).
I have enclosed the soils report from HBC Engineering for the project. Their recommendation for 40
daily repetitions is 7" 3500 psi concrete without lime stabilization.
If you have any questions please feel free to call.
Sincerely,
BROCKETTE'DAVIS' D ,R~,~_~
Project Manager /
JAR/ds
Enclosure (1) Geotechnical Investigation
C~vil 8: Structural Engineering · Surveying
4144 North Central Expressway. Suite II00 · Dallas, Texas 75204
(214i 824-3647 · Civil,'Survey Fax (214) 824-7064 · Structural Fax (214) 824-2586
./
GEOTECHNICAL INVESTIGATION
PROPOSED OFFICE/WAREHOUSES
GATEWAY BOULEVARD
COPPELL, TEXAS
HBC Report No. 42-1121-96
February, 1996
Prepared for:
Abbott Development
Alhambra, California
HBC ENGINEERING
J February 20, 1996 Fll~ 1'
Abbott Development ENGINEERING. INC.
812 Date Avenue, Suite A
Alhambra, California 91802
Attn: Mr. Walter G. Fuller
Re:
Geotechnical Investigation
Proposed Office/Warehouses
Gateway Boulevard
Coppell, Texas
HBC Report No. 42-1121-96
Gentlemen:
In accordance with your authorization, HBC has completed its geotechnical investigation at the above
referenced site. The work was accomplished following the general scope outlined in HBC's January
26, 1996 proposal. The results are presented in the attached report.
Please do not hesitate to contact us if there are any questions. We stand ready to assist in any way
during the design or construction phase of the project.
We appreciate the opportunity to provide these services.
Sincerely. ~..c.. ~....r~.~.~ ,~,,,
$?" o
HBC ENGINEE~NG, INC. ~....: .................
~ ~ /. 4-~ · t,~'...~ 5.~5.~...~
~eX k. WILliams, r.~.
Ralph B. Barnes, Jr., P~.
Principal
GEW:RBB:cc
CC:
Brockette Davis Drake/Robert Hill/Jim Riley (2)
Catellus Development Corporation/Stephen L. Bryan (1)
Gromatzky Dupress and Associates/Scott McCrary (2)
l-louston Office
2313 W. Sam Houston Parkv, ay N.nh: Suite 1()7
Houston. Texas 77043
(713) 722-0700 Fax 1713~ 722-0788
Dallas Of'rice
4747 Irving Blvd.; Suite 2(16
Dallas, Texas 75247
(214) 630-1011) Fax (214) 630-7{}70
Austin Office
3913 Todd Lane; Suite 312
Austin. Texas 78744
(512)442-1122 Fax (512) 442-1181
allowances in final grades should take into consideration post construction movement of flatwork,
particularly if such movement would be critical. Where paving or flatwork abuts the structure care
should be taken that the joint is properly sealed and maintained to prevent the infiltration of surface
water.
Planters located adjacent to the structure should preferably be self-contained. Sprinkler mains should
be located a minimum of five feet away from the building line. If heads must be located adjacent to
the structure, then service lines off the main should be provided.
Roof drains should discharge on. pavement or be extended away from the structure. Ideally, roof
drains should discharge to storm sewers by closed pipe.
Area Paving
Subgrade materials at this site are anticipated to consist of clays. These clays are subject to loss in
support value with the moisture increases which occur beneath pavement sections. They react with
hydrated lime, which serves to improve and maintain their support value. Lime stabilization is
recommended in areas subject to frequent, heavy truck traffic.
A minimum of 8 percent hydrated lime (TxDOT Item 264), by dry weight, should be used. The lime
should be thoroughly mixed and blended with the top 6 inches of the subgrade (TxDOT, Item 260).
Stabilization should extend a minimum of one foot beyond the edge of the pavement.
HBC ENGINEERING
42-1121-96 -11-
The subgrade should then be uniformly compacted to a minimum of 95 percent of ASTM D698 near,
-1 to +3 percent, the optimum moisture content determined by that test. It should then be protected
and maintained in a moist condition until the pavement is placed.
Area paving will be Portland cement concrete. In employee parking lots and other areas not subject
to tracks a minimum of 5 inches of 3000 psi concrete is recommended. In areas subject to track traffic
the following table of summarizes the estimated number of allowable daily repetitions of a fully
loaded tractor-trailer rig. The sections are based on the use of a minimum 28-day compressive
strength of 3500 psi and a 20 year design life. Sections are presented using an unstabilized, compacted
subgrade. It has been HBC's experience that a lime stabilized subgrade will improve serviceability
and reduce maintenance over the life of the pavement.
PAVEMENT ALLOWABLE DAILY
SECTION REPETITIONS
7" Concrete and no lime 40
7' Concrete w/lime 55
8" Concrete and no lime 90
8" Concrete w/lime 120
The pavement will be subject to movement due to volume changes in the clay soils. Flat grades
should be avoided with positive drainage provided away from the pavement edges. Backfilling of
curbs should be accomplished as soon as practical to prevent ponding of water.
HBC ENGINEERING
42-1121-96 -12-