PA9702-CS 981217MEMORANDUM
FROM THE
DEPARTMENT OF ENGINEERING
To: Gary Sims, Director of Leisure Services
From: Kenneth M. Griffin, P.E., Dir. of Engineering/Public Works W
Date: December 17,1998
RE: Coppell Aquatic and Recreation Center / Plan Review
The Engineering Department has performed a courtesy review of the plans for the Aquatic
and Recreation Center and have the following observations to offer:
1. The traffic flow for vehicles entering the site off of Parkway Blvd. could be somewhat of a
problem with vehicles entering the median cut on the western drive approach to drop off
children at the north end of the loop road. Any drop offs at that point will be on the
wrong side of the vehicle making it necessary to cross in front of the vehicle to access the
bridge and Aquatic Center.
2. I noticed several discrepancies between the civil plans and the architectural drawings
such as: thickness of concrete, under ground drainage pipes, pipe materials, etc. Those
two sets of plans need to be consistent.
3. City Standard Construction Details should be referenced throughout the plans. However,
the consultant did provide several details of which I have comments on:
a. The joint sealing compound should be silicon, not rubber.
b. Information should be provided as to the subgrade under the sidewalk. Our details
require sand.
c. City ordinances require lime stabilized subgrade, not a compacted subgrade, under
the pavement. In the past, we have allowed variances to that requirement by
increasing the thickness 1 or using a 4000 PSI concrete. In this case, your light duty
pavement would either be 6" at 3000 PSI or 5 at 4000 PSI. Your heavy duty
pavement would be 7 at 3000 PSI or 6 at 4000 PSI. Also, any work in the City right -
of -way, i.e., the drive approaches, median cuts, and the left turn lanes are required to
use a lime stabilized subgrade. There are no variances on the areas that we have to
maintain.
4. There is a good possibility that there will be pedestrian access to the site from the south of
Parkway Blvd. However, there is not a continuous sidewalk provided from Parkway to
the recreation center. You might want to consider providing sidewalk access parallel to
your loop road on both the east and west loops.
5. The transition for the left turn lane does not meet standards. There should be a 100 foot
transition (refer to Standard Construction Details). Again, as previously noted it should
be on a lime stabilized subgrade, not a compacted subgrade.
6. Brick pavers should be provided in the noses where the median cuts are provided
7. In reference to the General Notes, there are comments that state "materials and
construction shall conform to the City of Coppell Standards and Specifications, except as
noted here and approved by the City". The "except as noted here and approved by the
City" should be removed or clarification of who in the City will grant waivers. Some of
the items on these plans take a variance from this department.
8. Under General Notes there is a comment that says "see architectural plans for exact
building and related sidewalk dimensions ". As previously stated, the sidewalk
dimensions in the architectural plans do not match the civil plans. The architectural
plans show a 3 '/2" thick sidewalk which is not in conformance with the City's Standard
Construction Details.
9. On the Grading Plan, is there going to be some additional grading between the Stonemede
Subdivision and the western drive approach? It appears there is a low area that ponds
and holds water.
10. There is a comment on Sheet CO -5 concerning compaction to be a minimum of 93 %. All
compaction in areas where there will be vehicular traffic and especially in City right -of-
way should be a minimum of 95 %.
11. The City's Drainage Design Manual requires all low point inlets to be a minimum of 10
feet wide and discharged with a 21" minimum RCP lateral. These construction plans
show 8' inlets with 18" laterals. Also, some consideration should be given to discharging
the pipes into the direction of the flow into the creek.
12. The location of the inlet on the curb on the western drive has inadequate room for the
transition of the inlet.
13. The embedment detail is not consistent with the City of Coppell Standard Construction
Details. Our details require select material to 12" above the top of the pipe, not surplus
material from the excavation.
14. The existing 24" RCP on the east side of the outdoor pool should be stated as being
removed by the contractor.
15. Sheet C -10 shows constructing 48" Brooks Grate inlets in the fire lane on the north side of
the Aquatic Center. The only detail provided is for a 18 -18 -CB Brooks Grate inlet There
is no detail provided for the 48" inlet The City of Coppell Standard Construction Details
has grate inlet details and the one for the Brooks 18 -18 -CP does not appear to be
consistent with the Standard Construction Details. Additional information may be
needed to insure that it is an adequate catch basin, as it will ultimately be maintained by
the City. Also, as previously stated, all RCP's leaving low point inlets should be a
minimum of 21 ".
16. Prior to construction, a Notice of Intent Permit (NOI) should be provided along with a
Storm Water Pollution Plan. Your architect or engineer should be familiar with those
requirements.
17. On Sheet C -14, why is the water line headed north from Parkway Blvd. being proposed
beneath the paving? It appears it could go on the west side of the pavement, which would
provide much easier access in the future, without the removal of the concrete paving.
18. On Sheet C -15, the proposed water line on the east side of the outdoor pool is shown
under paving. It appears it could go outside the limits of the paving for ease of access and
maintenance in the future.
19. It appears that your double -check is shown on the wrong side of the domestic and
irrigation service.
20. Information should be provided on the flow lines and grades of the 8 PVC sewer leaving
the facility.
21. On Sheet L1.2, the drainage information is not consistent with the civil plans.
22. Is additional information being provided on the special paving around the facility?
The only sheets that Engineering looked at were C1 through C15 and LLI through L3.2.
The Engineering Department did not review the specifications for the project
If you should have any questions please feel free to call me.
ac ea�P¢�5