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HomeMy WebLinkAboutWPO200800038 Review Comments Road Plan and Comps. 2008-06-23ALg�,�� �'IRGINZ� COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project: WPO- 2008 - 00038, Westhall V Road Plan Plan preparer: Mr. Doug March, PE; W & W Associates fax 434.978.1444 Owner or rep.: Shiflett Farm, LLC fax 434.975.3542 Date received: 9 May 2008 Date of Comment: 23 June 2008 Engineer: Phil Custer The Road Plans for Westhall V, received on 9 May 2008, have been reviewed. The plans cannot be approved as submitted and will require the following corrections before approval can be granted: A. Road Plan comments WPO- 2008 -00038 1. VDOT approval is required. 2. The drainage easement between structures D12 and D9 needs to be 20ft in width. 3. Deflection angles should not be sharper than 90 degrees in inlet structures. Inlet D5 appears to have an angle sharper than 90 degrees. 4. The planting strip adjacent to the 6 spaces in Rella Court should be 2ft in width exclusive of the curb. [DM] 5. It appears that a low point exists in the parking lot of Rella Court away from Structure D12. The grading should be modified. [DM] 6. The maximum grade for parking areas is 5%. It appears that the spaces on the west side of Rella Court are all over this limit. [4.12.15] 7. In the profile, please show the locations of the VDOT crossdrains. [DM] 8. On sheet R -3, please provide the latest General Construction Notes for Streets from the design manual available online. [DM] 9. Inlets 19 and 23 are not placed in a sag condition according to the profile of Summerdean Road. The inlets appear to be located at Sta. 18 +25 but the low point is 18 +53. Engineering review would prefer the low point being farther away from the intersection. 10. Engineering review policy is to have 100% capture on inlets where overland flow does not drain to stormwater management facilities. Inlets 12, 8, 15, 18, 23, 19, 21, and 22 need to be sized using a storm with 6.5in/hr intensity because in case of failure the inlets flow to the stream rather than to the pond. Spread width requirements are reviewed with only a 4 in/hr intensity. [DM] 11. Overland flow relief (a graded swale) should be shown from structure 5 so the houses are not flooded by a failed inlet. [DM] 12. The radius of the horizontal curve on Summerdean Road needs to be called out. 13. Because Rella Court is slated to be a private street, it needs to be designed to VDOT standards. A plan and profile, similar to the other roads, will be needed in this set. [DM] 14. The spread for inlet 12 appears to be larger than the maximum 1Oft. [DM] 15. A road bond has not been calculated at this time. To request a road bond, the applicant must complete a Subdivision Road Bond Estimate Request and a Schedule of Completion for Bonded Improvements. The following are items that I have noticed during my review that are subject to VDOT review and approval. If VDOT has no concerns with the following items, then these comments may be ignored. 1. It appears that many of the K's are smaller than the allowed value for the roadways given the design speeds. [DM] 2. Many of the sag curb inlet calculations seem to be incorrect. The longitudinal slope of the gutter should be assumed to be 0.001ft/ft for the approach spread calculation for sag inlets. The longitudinal slope should not matter when the capacity of the inlet throat is calculated. For instance, the spread from the right approach of structure 23 (with a 0.001ft/ft longitudinal slope) is 12.5ft not 5.77ft as specified in the table. [DM] File: El_rp_PBC_08 -038 Westhall V Road Plans