ST9902-CS061129
Memorandum
Mr. Ken Griffin, P.E.
To:
Matt Atkins, P.E.
From:
Mark Holliday, P.E.
cc:
November 29, 2006
Date:
Re:West Sandy Lake Road – Federal Funding
As mentioned in our memo dated October 18, 2006, we have attached a preliminary Design
Summary Report (DSR) that TxDOT will require for the above referenced project. Based upon our
research and TNP’s recent history on a similar project, we think that a meeting should be held with
TxDOT representatives to discuss the DSR and determine what design elements will need to be
changed and what elements will need Exceptions and Waivers from TxDOT’s standards. Once you
have reviewed the DSR, we would like to meet with you to determine what items the City would like
to stand firm on and which items could have some flexibility. After our meeting we would like to send
the DSR to TxDOT and request a meeting to review and decide what design elements will need to be
changed. Once we have determined this information, we will be able to accurately assess our
amendment to our existing design contract. Below is a partial list of items that do not conform to
TxDOT Standards or items that will require more information.
Schematic Design – TxDOT will most likely require a revised schematic design. We will need to
identify exactly what elements they will require in the schematic in order to convert our
current design into an acceptable schematic.
TxDOT does not generally allow any utilities under the pavement sections. The existing 24”
waterline will be under a majority of the pavement section as will proposed storm drain
facilities.
TxDOT will most likely require a SUE to be performed.
TxDOT will require the traffic counts to be projected for various years, if they do not have the
projections already.
The parkway width (Border) of 12-feet is less than TxDOT’s standard of 15-feet.
Curb offsets are not currently proposed. We might be able to call the travel lanes 11-feet
wide with 1-foot offsets. This will meet their absolute minimum standards. The desirable widths
are 12-feet lanes and 2-feet of curb offset.
The median width of 16-feet is less than TxDOT’s standard of 20-feet.
The median deceleration and storage lengths are significantly less than TxDOT’s minimum.
The minimum values for these design elements are 75-feet and 100-feet, respectively.
The special bridge railing is not a TxDOT standard rail.
12160 North Abrams Road, Suite 508 Dallas, Texas 75243 214.461.9867 phone 214.461.9864 fax
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The City drainage design standards exceed TxDOT’s standards. The City will most likely be
asked to pay for the difference.
TxDOT will most likely not like the pavement design that has been completed. They require
special calculations and testing that was not provided in the geotechnical report.
TxDOT requires continuously reinforced concrete pavement and a 4-inch HMAC
underlayment along with stabilized subgrade. The City standard for this roadway is 8” of
reinforced concrete pavement and 8” of cement stabilized subgrade.
A scour analysis for Cottonwood Creek Bridge was not performed with the original
geotechnical investigation, and TxDOT will most likely require that one be completed.
TxDOT will require some type of accelerated contract procedure listed on DSR - 15.
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