HomeMy WebLinkAboutSDP200800086 Review Comments Final Site Plan and Comps. 2008-08-20From: Amy Pflaum
Sent: Wednesday, August 20, 2008 11:35 AM
To: 'msilman @terraconceptspc.com'
Subject: FW: SDP - 2008 -00086 Willow Glen
Marty,
I received Alan's out of office reply, so I am forwarding to you these new
comments I just received from VDOT on the Willow Glen project.
-Amy
From: Hamidi, Ajmal [ mailto: Ajmal.Hamidi @VDOT.virginia.gov]
Sent: Wednesday, August 20, 2008 10:59 AM
To: Francis MacCall
Cc: Denunzio, Joel D., P.E.; Philip Custer
Subject: SDP - 2008 -00086 Willow Glen
SDP - 2008 -00086 Willow Glen
Francis MacCall,
We have reviewed the road plans for the Willow Glen subdivision and have the
following comments in addition to those provided for the June 19th, 2008 Site
Review Committee Meeting:
The curve data for the horizontal alignment of the public roads need
to be provided, especially the centerline radii.
The minimum centerline radius for a subdivision street with a design
speed of 25 mph is 200'. The centerline radius of Heathrow Glen Circle appears
to be approximately 177' (this dimension is not shown on sheet 10).
The profiles should show vertical curves at the intersection tie -ins.
Several intersection tie -ins currently do not show vertical curves connecting
grade changes. For example, no vertical curve is shown where Willow Glen Drive
ties into Dickerson Road, where Shannon Glen Drive ties into Towncenter Drive,
or where Prestwick Glen Drive ties into Heathrow Glen Cycle.
The radius of the curbs at the entrance to the site from Towncenter
Drive is not shown. The radius must be sufficiently large so that the entrance
would be able to accommodate its design vehicle.
The sight distance lines need to be shown for the intersections
within the subdivision. The intersection sight distance for roads with a 25 mph
design speed is 280'. Of particular concern is the intersection of Shannon Glen
Ct. and Heathrow Glen Circle which does not appear to have sufficient sight
distance on the right side. The intersection sight distance lines for the
entrance off Towncenter Drive also need to be shown.
CG -12 standard ramps are needed at the intersection of Shannon Glen
Court and Towncenter Drive.
A flexible pavement design worksheet must be completed for each
public subdivision road. This worksheet can be found on Appendix IV of the VDOT
Pavement Design Guide.
The typical road sections on sheets 16 and 17 show incorrect
dimensions. For example, on the typical section C16 (Heathrow Glen Circle) the
travelway width is shown as 25' even though each lane width is 131. On typical
section D16 (Shannon Glen Court) the travelway is shown as 26' even though it
consists of two 13' lanes and two 2' wide gutter pans. The dimensions shown on
all the typical sections should be correct.
According to Appendix B of the VDOT Road Design Manual, trees should
be restricted from corners for distances of 30' in all directions in order to
maintain sight distance. This recommendation is not being observed at a few
intersections such as Shannon Glen Court & Towncenter Drive or Heathrow Glen
Circle & Shannon Glen Drive. Except at corners, small trees may be planted
within 3' of the back of curb on streets with design speeds of 20mph or less, or
on streets with on- street parking.
The following comments were provided in the June 19th, 2008 Site Review
Committee Meeting:
Sheet 7 - the entrance to Route 606 needs to have a layout as shown
in The Minimum Standards of Entrances to State Highways with adequate tapers and
curb offsets.
Previous comments recommended a turn lane off Hollymead.
The pavement width on Heathrow Glenn Circle should be reduced in area
where there will be no on- street parking. The layout will cause a situation
with parking in the driveways where the sidewalk will not and cannot be used
because cars will be parked on the sidewalk. This should be reconfigured.
The driveway entrances should be a CG -9D standard.
Material Reports for the con -span should be submitted to VDOT ASAP to
ensure adequate design.
We have reviewed the drainage plans for this development and have the following
comments:
Underdrains (VDOT standard UD -4) are needed underneath the curb and
gutter of roadway sections where the traffic volume is greater than or equal to
1000 vpd.
Sag inlets E15, E14 -1 & 03 have longitudinal approach gutter slopes
greater than 0.001 ft. /ft. Please have the engineer explain why slopes ranging
from 0.016 to 0.072 were used.
The pipe line from SDA3 to SDA2 has a slope greater than 16 %. This
line needs to be flattened or install anchor blocks added at every other joint.
The 96 "x48" arch pipe (con span) from SDJ2 to SDJ1 is under a private
street and should not require the design conditions outlined in HDA 06 -02.
If you have any questions, please contact Joel DeNunzio at (434) 293 -0011 ext.
120.
Thanks,
A.J. Hamidi, EIT
Tech III
Charlottesville Residency
(434) 293 -0011