SS9301-CS 940421 O. . oz 697
76097-0697
April 21 , 1994 9~ [8~7} z95-~98
Dan Frettinger
Kenko, Inc.
16415 Addison Road, Suite 308
Dallas, Texas 75248
Re: City of Coppell
Tunneling in Bethel Avenue
Dear Dan:
We are requesting permission to change the method and
material on certain portions of the remaining pipe to be
installed by the tunnel method. We have tested the soils
from the end of the completed installation at Station 105 +
60 to Station 124 + 50 and find that approximately one half
of the remaining pipe to be installed could be done using a
48" tunnel boring machine (TBM).
Where the TBM would be used, a temporary support
system, designed by a professional engineer registered in the
State of Texas would be used. PVC pipe, as called for in the
specifications, would be installed. It would be secured in
place and backfilled with a minimum of 200 PSI foamed grout.
We will furnish and install A-Lock adaptors for connecting to
the manholes. Ail changes in the pipe type will be done at
manholes.
By using the proposed alternate method, we will be able
to complete the work approximately ninety days sooner, which
will no doubt be pleasing to the people living in the area.
We hope to receive a positive response to this request
today and get this project completed as soon as possible.
Sincerely,
-- :? '
Charlie Griffith