SS9301-CS 911011 --' "' FILE COPY
TO: Howard Pafford, Water Superintendent
SUBJECT: Grapevine Creek Trunk Main, Branch 1 & II .
DATE: October 11, 1991 17 1@91
PUBLIC WOF KS
As per your request, engineering staff along with Gary Hendricks of
Shimek, Jacobs & Finklea have reviewed the above referenced final
construction plans, prepared by Ginn & Case, Inc., and have the following
comments that need to be addressed:
GENERAL COMMENTS
/ 1. On cover sheets provide:
a. Overall city-wide location map highlighting project location,
City Hall and major street.
b. Show names of City officials
- City Council - Director of Public Works
... - City Manager - City Engineer
~//2. Specifications, contract documents, and bid documents should be
reviewed by engineering prior to advertising'this project.
PVC pipe by Carlon. Is this pipe approved
3.
Plans
call
for
3O'
for use in these large diameters? ! understand a test section is
being reviewed, but has not been'approved. Why not allow other pipe
products. Allowing other pipe products will generally encourage more
competitive prices, suggest:
Thickwall RCP with Limestone aggregate T-Lock Rep
Hobas
Extra strength VCP
T-Lock RCP
The different pipe products would each require specifically designed
[>¢:~.~-~ embedments, again helping produce more competitive prices.
4. Load pipe deflection calculations should be provided for the soil
\" conditions and depths anticipated on this project. Are we sure the
Class 4 embedment is adequate in depths of 30 ft. in heavy clay soils?
Memo from M. Shohr~ Daneshmand
October 11, 1991
Page 2 of 3
5. The type of embedment to be used should be indicated in the profile
for reference by the inspector.
6 All manhole rim elevation, which are below the 100-year water
are to be 'S" sealed manholes. The should
surface, type plans
clearly indicate 100 year water surface and the type and diameter of
manhole to be constructed.
7 If there"~ more than 3 type "S" sealed manholes consecutively, than
alternate means of venting shall be provided. (Texas Department of
~ealth Regulations)
8. What is the contractors access to the Branch I project? Lots are
fully developed along both banks of Grapevine Creek. How is
materials, equipment and spoil moved on and off the project?
9. What are the provisions for Storm Drainage during Branch I
construction? What are the provisions for normal flows during this
10. The existing 12' sanitary sewer is to remain in service during
construction of this project. Close attention to trench safety
details is required to assure protection of the existing line.
11. Since the 12" line must be protected during construction, why not
leave it in service after the project is complete. It could serve as
a factor of safety against surcharge conditions.
12. Where the 30" sanitary sewer is located 3.5 feet inside the 20-foot
easement, the base of all 5-foot diameter manholes will be 8 inches
outside the easement.
13. Where the 30" sanitary sewer is located 2.0 foot inside the 20-foot
easement, the base of all 5-foot diameter manholes will be 2' -
outside the easement.
14. Where the sanitary sewer line is deep, does the existing easement on
the north provide adequate working space for implementing trench
safety?
15. Where the proposed sewer is in the flowline of the creek, and at
shallow depths, consideration should be given to the backfill
material. Is 85% compaction of native material adequate to prevent
washing out backfill and exposing pipe? Should we consider cement
stabilized backfill?
16. On the Branch I project, TOPO along the south bank of Grapevine Creek
appears incomplete. The lots along the south bank are developed.
Memo from Shohre Daneshmand
October 11, 1991
Page 3 of 3
17. The sewer capacity and velocities should be indicated on the profile.
18. The City-Wide Storm Water Management Study identifies several
drainage/erosion improvement projects along Grapevine Creek. It is
recommended that, as minimum, some temporary erosion control measures
be considered along the critical areas of Grapevine Creek if
possible. (See attached)
19. Sheet SD20 - the table of quantities for Class 4 embedment detail is
incomplete and the trench widths do not match the detail for class 4
embedment.
SPECIFIC COMMENTS
Specific comments are provided in mark-up form on each set of plans.
As these types of projects are of major significance to the City of
Coppell, we respectfully request that engineering department be considered
for more active participation early on. This would allow engineering
staff to provide relevant technical comments on a timely manner, resulting
in a better quality project, in the most efficient way. We hope that our
comments can be addressed, and if desired, we will meet with you to go
over the comments in more detail.
Attached please find the mark-up plans for Branch I ~ II, reflecting
staff's comments. Upon revision please return the attached mark-up plans
along with two (2) sets of revised plans, specifications and contract
documents. Should you have any questions in this regard, please let us
know.
cc: Gary L. Sieb, Director of Planning and Community Services
Steve Goram, Director of Public Works
Sanford Case, Ginn & Case, Inc.
Gary Hendricks, Shimek, Jacobs & Finklea
GRAPECRK
MATCH SHEET 14'
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