SS9901-CS040707TurnerCollie( Braden Inc.
Engineers · Planners · Projec! Managers
July 7, 2004
TC&B Project No. 052131124.0001
David Holland
Senior Vice President
Mastec North America, ]nc.
4747 Irving Blvd., Suite 221
Dallas, Texas 75247
Re:
City of Coppell
Deforest Road Lift Station Improvements
Force Main Line D
Project No. SS 99-01
Dear Mr. Holland:
This letter is in response to your letter of June 24, 2004, regarding concerns related to performance
of the SDR 17 high density polyethylene (HDPE) pipe specified for this project. We have
reviewed the proposed pipeline profile based on the approximate access pit locations provided with
your bid and have verified our calculations for pipe performance under the following conditions:
· Construction / pipe installation (short-term condition)
· Normalpipeline operation (long-term condition)
· Pipeline repair/maintenance (short-term condition)
The pipe must be filled with water prior to installation in accordance with the project
specifications, and deep portions of the bored sections need to be kept full of water during
construction. However, the more shallow sections at the access pits (at the beginning and ending
of each bored section) can be empty during construction without adversely impacting pipe
performance. Calculations for normal pipeline operation and short-term repairs/maintenance
indicate the pipeline will perform as designed under these conditions.
If you have questions or require additional information, please call me at 972-735-3056.
Sincerely,
Erika K. Cooper, P.E.
Project Engineer
cc: Ken Griffin, P.E. - City of Coppell