HomeMy WebLinkAboutSDP202100011 Correspondence 2021-05-05 (2)TIMMONS GROUP
May 5, 2021
John Anderson
c/o: Cameron Langille
County of Albemarle
401 McIntire Rd, North Wing
Charlottesville, VA 22902
608 Preston Avenue P 434.295.5624
Suite 200 F 434.295.1800
Charlottesville, VA 22903 www.timmons.com
RE: Boys & Girls Club Driver's Ed — Final Site Plan Review — SDP202100011 - Comment
Response Letter
Dear Mr. Anderson:
We have reviewed your comments from March 28, 2021 and made the necessary revisions.
Please find our responses to the comments below in bold lettering.
1. VSMP-WPO plan must be approved prior to FSP approval. WP0202000051 is under
review.
Acknowledged.
(FSP) Acknowledged.
2. C5.0, C5.1: Label underground detention systems in plan/profile view, to correlate or
distinguish systems from one another.
Underground detention systems have been labeled on Sheets C5.0—05.1.
(FSP) Addressed.
3. C7.0:
a. Str. 106, 15" basin / vertical structure is proposed with 24" DIA upstream /
downstream pipes. Confirm this riser / pipe diameter combination works.
Per comment 3b, this comment is no longer relevant.
(FSP) NA, per comment 3b.
b. Comment 3.a. irrelevant, since: Ensure all structures (pipes, inlets, grates, risers,
MHs) within public drainage easement/s conform with VDOT R&B standards.
VDOT Std. for Nyloplast dome grates / risers may not exist, though HDPE pipe is
permissible. Replace Nyloplast risers with VDOT Std. MH wherever they exist
within public drainage easement, i.e., receive runoff from a public road or are
located downstream of a SWIM facility (detention, for example, Str. 106, for
example).
Structures within the public drainage easement have been replaced to meet VDOT
standards. See plan on Sheets C5.0 — C5.1 and profiles on Sheets C7.0 — C7.1.
ENGINEERING I DESIGN I TECHNOLOGY
(FSP) Addressed.
c. Nyloplast (in -line v. terminal) risers may represent near -term savings, but for
storm conveyance requiring up to 24" DIA pipe-up/downstream of Nyloplast
risers, Std. VDOT MH structures with VDOT Std. grates appear a more cost -
balanced approach, in the long term. Nyloplast risers are likely less durable for
systems with pipe diameter in the 18"-24" DIA range. Also, it is important to
provide storm conveyance system access via MH lid / frame, w/ steps.
Per response to 3b above, structures within the public drainage easement have been
replaced to meet VDOT standards. In doing so, the larger -diameter Nyloplast
structures have been removed.
(FSP) Addressed.
d. Provide and label %" steel plate in MH floors if vertical interval (INV IN/OUT) >4'
(Str. 106, for example). Ref. VDOT Drainage Manual, pg. 9-38.
Storm pipes have been modified due to layout and grading changes; however, this
label has been provided as requested where vertical interval is larger than 4'. See
Sheet C7.0.
(FSP) Partially addressed. As follow-up: Provide steel plate label for Str. 102.
A label has been added to structure 102 on Sheet C7.0.
4. C7.0, C7.1: Please label SWM detention systems to distinguish one from the other.
SWM detention systems are labeled on Sheets C7.0 — C7.1.
(FSP) Addressed.
5. C0.0: Include reference to VSMP / WPO202000051.
Reference has been added to Sheet C0.0.
(FSP) May persist. Cannot locate reference. Please direct reviewer to C0.0 reference.
Reference has been clarified on Sheet C0.0.
6. C0.0 Recommend include ref. to SDP202000069.
Reference has been added to Sheet C0.0.
(FSP) Addressed.
7. C4.1: Recommend a low -profile wall (1.5'-2' ht.) between 5' walk and 24' w drive aisle
adjacent to grass seating area. Spectators may occupy walk, at times, as non -
pedestrians. Patrons / guests may congregate / stand on the walk to watch events.
Immediate proximity of passing cars with no separation, and of vehicles reversing from
spaces, and an uncertain mix of young drivers -youthful spectators/club patrons (often
distracted) at this location, gives pause. Recommend provide a barrier.
Sidewalk width has been increased to 6 feet in order to provide more walking space and
separation from the drive aisle.
(FSP) Withdrawn.
8. C4.2: Engineering expresses reservation with crosswalk proposed at an angle since
detectable surfaces may misdirect visually impaired pedestrians to a curb, or parking
space rather than to a CG-12 receiving ramp.
The crosswalk location has been modified so that it is no longer angled and is safer for
crossing pedestrians.
(FSP) Addressed.
9. C4.2, C5.1: Revise CG-2 to CG-6 where runoff concentrates against curb; for example,
drop-off lane that connects with Lambs Lane in front of the building.
CG-6 has been added where runoff concentrates. See Sheets C4.1— C4.2 and C5.0 — C5.1.
(FSP) Addressed.
10. C5.0: With WPO, provide additional details for discharge from pipe 301. Ultimate
discharge from this portion of site is unclear. Also, revise storm pipe profile, C7.1, at this
location to clarify whether pipe 301 discharges above or below grade. Any existing
storm system element/s relied upon for this development must be evaluated for fitness
and capacity to limits of analysis, including, at a minimum, visual check on integrity and
condition of any existing pipes. Image below appears to indicate inverts inaccessible.
Pipe 301 discharges below grade, tying into the existing manhole structure. The profile has
been updated to remove end section label and clarify intent at this location. Additionally, a
label has been added requiring contractor to field verify condition and invert of structure prior
to construction.
(FSP) Addressed. [Image removed with FSP comments.]
11. C5.0: With WPO, provide overview (large-scale inset) to show graphically how this
portion of the site discharges to slopes below Ivy Creek School Main Building. Evaluate
these sections of existing storm conveyance for integrity and fitness.
This portion of the site is tying into the existing manhole, as shown on Sheet C5.0.
Downstream pipes have been evaluated, and calculations are provided within the design
calculations, provided with the WPO submission.
(FSP) Addressed.
12. C5.1:
a. Ensure parking conforms with an available option listed at ACDSM, p. 17 (i.e.,
may require bumper blocks).
A 6'-wide sidewalk is provided adjacent to parking. This has been labeled on Sheets
C4.1— C4.2. Therefore, bumper blocks are not required.
(FSP) Addressed.
b. With WPO plan, evaluate potential for erosion along channel formed by existing -
proposed contours; ensure velocity is non -erodible. Provide typ. Channel section
at blue line location, below.
Channel sections and ditch calculations have been provided on Sheet C5.0 for all
proposed drainage ditches.
(FSP) Addressed. [Image removed with FSP comments.]
c. Revise angle of entry of pipe 215 into Str. 204, since angle is acute. Change in
direction in flow through a MH structure should be >90-deg to limit potential for
obstruction.
The storm pipe layout has been revised; no acute angles are proposed. See Sheets
C5.0 — C5.1.
(FSP) Addressed.
d. Handrails are required for tiered retaining walls (C5.0, C5.1) for safety, and to
discourage trespass.
Tiered retaining walls are no longer proposed with this project. However, handrail has
been provided with retaining walls where required to provide visual and physical
barrier. See Sheets C5.0—05.1.
(FSP) Addressed.
e. Recommend handrail at building exterior, NW corner of narrow main level west
wing. At this location, an esplanade abuts a steep graded slope that falls to
tiered retaining walls.
Handrail has been provided where suggested. See Sheet C5.1.
(FSP) Addressed.
f. Reference and incorporate grading standards at 18-4.3.3 into design; please
especially note requirements at 18-4.3.3.B.1, concerning rounding off. [Eff.
7/15/20).
County grading standards have been incorporated into design.
(FSP) Addressed. Also: Engineering does not object to Timmons Group Boys & Girls Club
— Driver's Education Critical Slopes Waiver— Special Exception Request d. 02/10/2021,
to disturb approximately 0.40 Ac. Critical Slopes. Note: Engineering did not object to a
previous design that disturbed = 0.79 Ac. Critical slopes. A separate email / Memo to
follow.
Acknowledged.
g. Ensure runoff from inclined paved access to 4 wooden sheds does not enter
proposed dumpster enclosure, but instead reaches Str. 208.
The proposed dumpster enclosure has been relocated per owner recommendations.
This comment is no longer applicable.
(FSP) NA.
h. Resolve inlet Str. 206-sidewalk conflict.
Conflict has been resolved. See Sheet C4.2.
(FSP) Addressed.
Additional FSP review comment possible.
Acknowledged.
(FSP) As follow-up:
i. C7.0: Provide Note specifying % compaction in fill section beneath pipe 214E
given flat slope (min. 0.5%), pipe length, and HDPE material. Deflection at 0.5%
slope may cause post -construction repair or bond issues. Image, below.
A note specifying required compaction has been added to the profile on Sheet
C7.0.
ii. C7.0: Provide safety slab for MH structure ht. > 12', Str. 108, 110, for example.
A note has been added to Sheets C7.0 — C7.1 requiring safety slabs where
manhole heights exceed 12'.
iii. C8.0 / C4.1: Coordinate design of sanitary pump station with VDH. Provide
reliability data/information required by VDH. Engineering Division has not
reviewed Bruce W. Strickland, Jr, PE, pump station design: plan / section views;
site plan; pump curves. County Engineering makes no warranty concerning
fitness of pump station or FM design relative to state sewage collection and
treatment (SCAT) regulations. Also, recommend coordinate pump station /4"
force main (FM) design (from new development to point of connection with
existing FM) with ACSA/RWSA.
VDH does not have jurisdiction over the wastewater pump station; it's
regulated by DEQ. However, repair/replacement projects where the capacity
and/or function is not changed do not require a Certificate to Construct from
DEQ. This project includes replacement of an existing wastewater pump
station. It was designed in accordance with SCAT Regulations and meets Class
I reliability requirements. The pump station and force main will be privately
owned and maintained by ACPS, but as a courtesy we have notified
ACSA/RWSA of this project.
We have included PDF copies of the plans and calculations for your review. If you have any
questions or comments, please feel free to give me a call at 434.295.5624 or email at
kim.roeser@timmons.com .
Sincerely,
K6k�wy Kwek
Kim Roeser
Project Engineer