HomeMy WebLinkAboutWPO200800054 Review Comments Road Plan and Comps. 2008-08-20From: Hamidi, Ajmal [ Ajmal.Hamidi @VDOT.virginia.gov]
Sent: Wednesday, August 20, 2008 2:04 PM
To: Philip Custer
Cc: Denunzio, Joel D., P.E.
Subject: Faulkner Falls Subdivision
Faulkner Falls Subdivision
Phil Custer,
We have reviewed the above plan and have the following comments:
a.. The design ADT for the Reivers Run needs to be provided so that the
adequacy of the pavement and taper designs can be verified.
a.. The sight distance lines must be shown at the intersection of Reivers Run
and Route 676 as outlined in Appendix B of the VDOT Road Design Manual. Route
676 is a two lane major road with a speed limit of 40 mph. Therefore, the
required intersection sight distance is 445' according to the VDOT Minimum
Standards of Entrances to State Highways.
b.. The entrance of Reivers Run should provide a 50' landing in which the
vertical grade does not exceed 2 %. The current design provides less than 30' of
landing.
c.. The proposed radius to the edge of pavement of the cul -de -sac is 40'. The
minimum radius for a cul -de -sac is 45' unless specifically approved by the
County in consultation with emergency services.
d.. The ditch computations shown on sheet 5 are not sufficient. Ditch
computations must provide the velocities and depths at each station as described
in chapter 7 of the VDOT Drainage Manual. The ditch linings should then be
determined based on these computations. The LD -268 VDOT form is recommended for
this procedure.
e.. The proposed ditch design makes extensive use of a rip -rap channel.
According to chapter 7 of the VDOT Drainage Manual, the use of standard riprap
for linings in standard roadside ditches is not typically permitted. The normal
progression of ditch lining follows: earth (0 to 2 fps), EC -2 (2 to 4 fps), EC -3
Type A (4 to 7 fps), EC -3 Type B (7 to 10 fps), and finally concrete (> 10 fps).
The rationale for using the rip -rap channel must be provided before VDOT could
consider making an exception.
If you have any questions regarding these comments, please contact Joel DeNunzio
at (434) 293 -0011 ext. 120.
Thanks,
A.J. Hamidi, EIT
Tech III
Charlottesville Residency
(434) 293 -0011