HomeMy WebLinkAboutSUB201500020 Correspondence Road Plan and Comps. 2014-07-03 COUNTY OF ALBEMARLE
'Nye Department of Community Development
401 McIntire Road,Room 227
Charlottesville,Virginia 22902-4596
Phone(434)296-5832 Fax(434)972-4126
Project: Old Trail Village-Block 12, Phase 2
Plan preparer: Roudabush,Gale&Assoc.,Inc[914 Monticello Road,Charlottesville,VA 22902,
cmulligan @roudabush.com
Owner or rep.: March Mountain Properties[1005 Heathercroft Circle,Suite 100,Crozet,VA 22932,
dave @oldtrailvil lage.com]
Date of comments: 3 July,2014
(Rev. 1) 18 Mar 2015
Reviewer: John Anderson
A. Road Plan(SUB201500020-prior design:SUB201400080)
Furnish pipe and inlet computations(inlets: spread'capacity,elevations,descriptions;pipes: flow,velocity, L. DIA, inverts,etc).
No roadway storm collection system computations or calculations are included with Road Plan,though computations may have
been submitted directly to VDOT. (Rev. 1)Addressed. As follow-up: Using Storm Sewer Design/Hydraulic Gradeline tables
(2/4/2015),it appears several sections of pipe are surcharged during a 10-yr event. (Unless review error)revise so system
contains 10-yr event without surcharge.
The capacity of the outflow pipe was revised to provide capacity. The remainder of the storm sewer
pipe capacities were verified so as to exceed the 10 year design flows within each pipe. Accordingly,
a `surcharge' does not exist. The HGL computations take into account pipe friction, bend, inlet and
exit losses to predict a worse case condition that may cause the inlet/mh lids to `shoot off' due to a
turbulent & pressurized condition. Since here,the HGL elevations fully remains less than any inlet
tops,the design exceeds any and all VDOT hydraulic standards. There isn't a standard to mandate
that the HGL elevation remain less than the top of the pipe.
FROM INV upper pipe DIA/top of pipe Elev. Upstream Elev.(same location)
(see HGL,2/4/2015) Diff.
16 to 14(outfall) 644.25' 2.5'/646.75' <HGL Elev, 647.04 (0.29')
18 to 16 645.50' 2.5'/648.00' <HGL Elev, 648.12 (0.12')
18B to 18 655.25' 2.5'/657.75' <HGL Elev, 658.09 (0.34')
22 to 18B 657.10' 1.25'/658.35' <HGL Elev, 658.48 (0.13')
As reminder,please perform checks. 10-yr event must be contained(open channel flow capacity).
The storm sewer pipes outfall within the proposed BMP facility grading and easement, and have end
sections.
2. The profile for Rowcross Street should clearly define where the profile for Block 15 begins and ends (VDOT
comment#16,V DOT comment letter dated June 12.2014). (Rev. 1)Addressed.
3. VDOT must approve road plans. VDOT comments sent to Applicant(project primary contact)via e-mail
attachment, 12-Jun-14. (Rev. 1)Withdrawn—no public roads.
New
1. Remove sheet 4,Site Plan,from Road Plan. Retain/preserve plan notes,as appropriate.
2. If retain sheet 4 Notes,delete Note 5.
Sheet 4 was retained for pertinent dimensions & information. Note removed.
310.1' Engineering Review Comments
Page 2 of 3
3. Replace roll top curb detail,sheet 13,with VDOT roll-top detail. Details are nearly identical.
VDOT roll-top curb detailNDOT Road Design Manual,App.B(1)-4.G.
http://www.extranet.vdot.state.va.us/locdes/Electronic Pubs/2005%2ORDM/AppendB(1).pdf .
OK
4. Include VDOT Road Design Manual roll top curb Notes,at your discretion:
5. Sheet 9/Rowcross Street profile:PVT Sta. 11+02.50 to End Block 12/Beginning of Block 15,Sta.
12+44.98,grade is 0.62%. This is inconsistent with Approved block 15 road plan grade of 0.92%. Revise.
OK
6. Rowcross St/End block 12 Elev.665.02'differs from Approved block 15 road plan,same location. Revise.
OK
7. Sheet 10,storm sewer profiles: storm system is stationed,but not with road stationing. Furnish stationing
that correlates storm system Dls to road system(stationing)for review,construction,and inspection.
Added storm sewer to the road profiles.
8. Sheet 10,Str. 18/MH requires safety slab,but safety slab(VDOT SL-1)cannot be located below any inlet
pipe of 30"diameter or greater. Revise design at this location,consistent with VDOT detail. Safety slab
required for MH depth> 12'(link:
http://www.extranet.vdot.state.va.us/LocDes/Electronic Pubs/2008Standards/Section 100/106 14pdf )
Revised to be less than 12' in depth.
9. Include SL-1 detail(VDOT Road&Bridge Stds,2008):
See above.
‘41 Engineering Review Comments
Page 3 of 3
10. Sheet 10/storm sewer profile#11 -#1 (outfall),and#24-#14(outfall):Extend existing contours beyond
pipe outfalls,if they actually extend beyond outfalls. At some point,proposed and existing should meet.
11. Sheet 10/storm sewer profile#24-#14(outfall): Pipe 15 outfall appears exposed. Provide sufficient cover.
Crown of pipe should not be exposed.
12. Sheet 10/storm sewer profile#11 -#1;profile#24-#14: Provide VDOT end sections,pipes 2, 15.
13. Remove sheet 14.
14. Title plan set,Road Plan,not Final Site Plan.
15. Please cross-reference these Road Plan comments with Site Plan comments sent this date(identical plan set
was submitted for final site plan and road plan—we discourage this). Comments requesting removal of Lots
13-24;sheet 3 comments;and several other comments apply to road plan and site plan alike.
Please call if any questions. 434.296-5832—x3069