WA9302A-CS 960311 SHIMEK, JACOBS &
CONSULTING ENGINEERS
8333 Douglas Avenue,//820 Dallas, Texas 75225 (214) 361-7900
ROSS L. JACOBS, P.E.
RONALD V. CONWAY, P.E.
JOHN W. BIRKHOFF, P.E.
JOE R. CARTER, P.E.
GARY C. HENDRICKS, P.E.
March 11, 1996
C. L. SHIMEK, P.E.
I. C. FINKLEA, P.E.
JAMES E. LAUGHLIN, P.E.
North Te s Municipal Construction Co., Inc.
5D6a~~~t5206
Re: City of Coppell
Village Parkway Pump Station Addition
Electrical Duct Bank Relocation
Gentlemen:
We have field measured the location of the existing electrical duct bank which you exposed during your
excavation for the construction of the City of Coppell, Village Parkway Pump Station Addition project. As
we suspected, the duct bank is in conflict with the proposed construction. We are attaching a drawing, titled
"Field Change No. 1" showing the measured location of the electrical duct bank.
In order to avoid the relocation of this critical circuit, we have investigated alternative pump station layouts
that would allow us to leave the existing duct bank in place. The attached drawing shows Pump No. 6, and all
associated piping shifted 4-feet to the west. The pump is also revised to a right hand drive unit rather than a
!eft hand unit as originally designed. Although it appears this layout would allow the City to leave the existing
duct bank in place, several concessions have to be made in the design. For example, the access door have to
be reduced to 8-feet in width, the pump suction lines shifted to within 18-inches of the now narrower access
door, an additional foundation pier is required, additional grade beam reinforcing is required; and most
significantly, clear, unobstructed access to the motor for Pump No. 6 is eliminated.
After reviewing the modifications necessary to allow the electrical duct bank to remain in place, the City
directed us to investigate the down time required to relocate the electrical service. This pump station is the
primary source of water supply for the City' s water distribution system. Further, the City has only one
elevated storage tank with a capacity of 1.5 million gallons. During the maximum daily water demand
conditions that are expected to begin in a few short weeks, the City does not have the luxury of allowing the
Village Parkway Pump Station to be off-line for even a brief period of time.
With the assistance of your electrical sub-contractor, we have evaluated the work and coordination effort
required to relocate the electrical service. It was the opinion of you electrical subcontractor that service could
be relocated with a down-time of roughly 4 to 6 hours, with a chance that the station could remain on line and
at least partially in service during the entire process. We have discussed this time estimate with the City of
North Texas Municipal Con' ction Co., Inc.
March 6, 1996
Page No. 2
Coppell, and they believe with careful coordination the water distribution system can be operated without
Village Parkway Pump Station for a period not to exceed 6 hours.
Please proceed with the work required to relocated the existing electrical service as provided in the contract
documents for this project. Prior to beginning any work on the relocation, please submit your plan of work
and expected schedule. In your plan of work, you should include provisions for emergency electrical service
in the event the pump station can not be energized using either the existing or new electrical service within 6
hours after the switch over begins. Again, this work must be closely coordinated with the City of Coppell's
Director of Utilities.
If you have any questions or need additional information, please do not hesitate to contact us.
Gary C. Hendricks, P.E.
Enclosure
cc: ,AClr. Ken Griffin, P.E.
Mr. Ted Dutt
Mr. Larry Davis
i 5'-0' """ 16'-1 172' t ,)'-2 1/2'
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(FIELD VERIFY)
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