SS9901-CS050202Turner Collie _ Braden Inc.
Engineers · Planners ° Project Managers
17300 Dallas Parkway
Suite 1010
Dallas, Texas 75248
Tel: (972) 735-3000
Fax: (972) 735-3001
February 2, 2005
TC&B Project No. 052131124.0001
Rick O'Dell
City of Coppell
P.O. Box 478
Coppell, Texas 75019-4409
City of Coppell
Deforest Road Lift Station Improvements
Force Main Line D
Project No. SS 99-01
Dear Mr. O'Dell:
This letter is response to our conversation regarding the question posed by the Line D Contractor
(Mastec North America, Inc.) yesterday regarding the installation depth for Line D in the vicinity
of Samuel Boulevard.
Our understanding of the information Mastec provided to you is as follows: Drilling began at a
location approximately 400 feet south of Samuel Boulevard and proceeded to the north.
Approximately 270 feet from the bore pit, the depth to the pilot hole was approximately 22.5 feet.
This is about 8 feet deeper than the design depth. Mastec indicated that the deviation from the
design depth resulted from difficulties encountered during the drilling operation while attempting
to make the necessary horizontal curve.
There are no utilities in this area that require the additional depth of cover over the pipe. Any
increase in depth increases the external loads on the pipe and exceeds our initial design criteria.
Therefore, we do not recommend installing the pipe at this increased depth.
If you have questions or require additional information, please call me at 972-735-3056.
Sincerely,
Project Engineer
Ken Griffin, P.E. - City of Coppell
Ben Bishop, Mastec
Engineering Excellence for Over One-Half Century