Prologis Park 1_2-CS180614 E! HALFF
June 14, 2018
AVO 32211
Mr. George Marshall, P.E.
Engineering Manager
City of Coppell
265 E. Parkway Boulevard
Coppell,Texas 75019
Re: Engineering Review#1
Prologis Park One Twenty One, Buildings 1 and 2—City of Coppell
Dear Mr. Marshall,
Construction plans for the referenced project were received by Half Associates, Inc. on May 14, 2018. The
construction plans were prepared by the Richardson office of Halff Associates, Inc. The project is for the
design of two industrial buildings and site at the northeast corner of Sandy Lake Blvd. and Freeport Pkwy.
Response to comments are as follows:
Cover Sheet
1. Include the approved site plan in the permit set. Revised.
General Notes—Sheet C0.02
1. Revise 7" and 8" paving to be 3600 psi with #4 bars. Revised. 7" paving at 3600 psi with#3 bars
per Geotech report. Matches other buildings.
2. Use DR 14 water pipe. Revised.
Paving Plan—Sheet C1.01
1. Stamped concrete should be full width of driveway opening. Revised.
2. Use a different line type and thickness to identify the retaining wall. Revised.
3. Revise 7" and 8" paving to be 3600 psi with #4 bars. Revised. 7" paving at 3600 psi with#3 bars
per Geotech report. Matches other buildings.
4. Normally the FD requires the firelane to be painted to the curb line. Revised.
5. Add note on paving sheets: No lane closures allowed during peak hours. Allowable lane closures
9am to 3:30pm. Revised.
Left Turn Paving Plan—Sheet C1.02
1. Provide a detailed Grading Plan, Landscape Plan, Lighting Plan, Irrigation Plan for this island.
Landscape will provide detailed plans for island.
2. Paving thickness shall match existing. Revised.
3. The dimensional layout of this nose does not meet city standards. Revise. Revised.
Grading Plan Detail—Sheet C2.02
1. Check slopes here do not exceed 4:1. Revised.
EjE HALFF
Grading Plan Detail-Sheet C2.03
1. Regrading in this area will be necessary due to erosion issues.. Revised.
2. Provide some sort of guard for both people and vehicles at this 6'+drop off. Revised.
Grading Plan Detail-Sheet C2.04
1. Extend the view past the matchline. Revised.
2. Revise grades to not exceed 4:1. Revised.
3. Not sure this is going to work out with the neighbors, this looks like lot to lot drainage. Revised.
Swale put in behind curb, between top of wall and curb. See detail this sheet.
Drainage Area Map-Sheet 3.00
1. Label the storm drain lines and sizes in plan view. Revised.
2. Label the inlets in plan view. Revised.
3. Provide a basic calculation for Tc on the roof area to the inlets. In addition, a 0.9 for a roof
seems off as area C-3 is a 0.9 as well. 0.95 seems more appropriate. Per the Coppell Design
Criteria Manual Section II.B,the minimum inlet time of 10 minutes is used for all inlets. A
runoff coefficient of 0.9 is used for the entire site based on the Dallas Drainage Design Manual
(1991)Section IV Runoff Coefficient Table for Light Industrial land use. While there are areas
where the actual runoff coefficient may be closer to 0.95,there are large pervious areas
where it would be closer to 0.30. 0.90 runoff coefficient meant to reflect overall site
characteristics for light industrial.
Storm Drainage Plan/Profile-Sheet 3.02
1. Label HGL elevations in profile. Revised.
Storm Drainage Plan/Profile-Sheet 3.03
1. Show pond contours. Revised.
2. Label what appears to be rip-rap. Revised.
3. Water is too shallow. Label flowline. Revised.
4. If the 48" pipe starts the slope higher than the frictional slope of the HGL then it would be
remain in partial flow.Typically ends are less than Sf. 100-year HGL of pond labeled in profile.
HGL starts at the soffit, and is in partial flow in steep section of pipe, HGL resets at top of
lateral B-1, then the HGL frictional slope is steeper than pipe slope.
5. Label HGL elevations in profile. Revised.
Storm Drainage Plan/Profile-Sheet 3.04
1. Show to STA 0+00 Line C. Not able to fit on page, but match line put in on Sheets C3.03 and
C3.04.
2. Label flowline of water crossing. Revised.
3. Label HGL elevations in profile. Revised.
Storm Drainage Plan/Profile-Sheet 3.05
1. Label flowline of water crossing. Revised.
2. Label HGL elevations in profile. Revised.
3. Change the SD alignment so it isn't directly under the FH. Revised.
j HALFF
Water Plan—Sheet 4.01
1. Make an additional connection to either Coppell Road or to Sandy Lake. Revised. Used 8"stub
out on Coppell Road.
2. Remove Detail 4155 from water note. Revised.
3. Records indicate this is a 4" stub. Revised.4"x2" Reducer put in.
4. Show the FH. FH called out in note to the right. STA 4+25.0 LINE W2.
5. Fire sprinkler line design needs to be done at this time. Sprinkler design will be design-build.
Note removed.
Wastewater Plan—Sheet 5.01
1. Install Outside Drop in SSMH. Revised.
Wastewater Profiles—Sheet 5.02
1. Label Crossings. Revised.
2. SSMH at pipe slope changes. Revised.
Erosion Control Plan—Sheet 6.01
1. Provide a sedimentation basin per city detail 1100. Revised.
HALFF ASSOCIATES, INC.
TBPE Firm No. 312
/ °(/(//11011'
Robert Gossett, P.E.
Attachment: Construction Plans