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HomeMy WebLinkAboutSUB200300020 Calculations Road Plan and Comps. 2004-05-14 Friday, May 14, 2004 9:39 AM Jo Higgins 1-434-823-1720 p,01 .5 -- ENGINEERS SURVEYORS PLANNERS ASSOCIATES FACSIMILE TRANSMITTAL SHEET To: Jo Higgins From! Ryan Lavinder Organization: PDL,LC. Date:5/13/C4 Pax number: 434-823-1720 Total No.of pages inclucling cover: 6 Phone nurnbex: 434-823-1224 Project number_ 204046.00 ,l4/© u e 're Is tielf)79 014 edialrArgqi 4 I alma 16115 054e— C-4/0 V e±(' `, VV l� .�w�llJJ 11;14AnfilL et141 v C....40,ok 147 Mill Ridge Road•Lynchburg,Virginia 24502 Telcpbone(434)582-6175•Fax(434)582-6179 I 'd SG 28S (17E1P) sese t oossd mm dal:10 40 E r Reu Friday, May 14, 2004 9:39 AM Jo Higgins 1-434-823- 1720 p.02 1 \ \IT 1 \ \ V- ---- ;11! /614 \ .1.i.4‘,1,1 7Viti \ iii '--\ -----\\--- --: \\ . 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I.--i_ .... Z a a a La en . ).., .... e I 8 E I I 1 - C.J • Gt (-7 • 2 C „, n 1 z. . _ , I 1 H .1. ..z. I - ; 1 , ce a. CS ...) : .... ei . ..• . . 1. _ . 1 1 I I Figure 7. • ...) _ •.';:,-:'. Friday, May 14, 2004 9;39 AM Jo Higgins 1-434-823-1720 p.08 sow sire . CHART 5 180— ^18,000 169 8,004) EXAMPLE (() 136 —61p00 0.34:.er..(l0rw11 6 {2) —4,000 ..••,.. 144 ,-4,000• �� ew 3- 6- (3� 13 2 I - 0.01 = c 3.000 S 6. 1Y0 - G pl 1.4 3.4 • 1 . r 2,000 (J 1.1 43 S. i a 131 1.2 4.4 108 e i 96 2 - 1,000 _ 800 - 3. - 500 a. 400 —„ "- i 72 I 2. Z y1 300 ��/_ 3 .S ,. I r. 200 _,- �. r i-6G — ? ; ♦L'� - 4- loo / a } —4)e SO a L >[ - e0 ` —42 /1^ 00 ^ 1.0 .-.1.0 / Q p 4Q P. 1.0 0: p 1W- .40 bmi A C40 g a W 0 SCALE TYPE .s 4) '`33 �q t0 111 4.r4..II o .4 -.8 0 1�/ : 30 (✓S1 bloated$e u•r•e.. 4 u �, ^ ploy. _ .n a 27 1� f, r t o ..41.411.. 1 e .T ..,7 El 6 1...e au.RI.e(4)1 Ir•1•.1 .. r- 21 4.rs..lalq le 1••I4 O.II.. 4..011101:.e6.•411 11.4 Ow mill t' U•-4 . • .I..,r n r•.. • ■■ .6 . - 2 - 13 (0T 0 57017-14/ -.� ` ,.� cfS Q,4) ,- - 12 HEADWATER DEPTH FOR C. M. PIPE CULVERTS ♦•TMr �:~a' A.,or WPIC 001109 am ..a WITH INLET CONTROL. --3 9 "d 6LT9 SBC (*E41 cazergoocsy p{0 dOC=TO 40 ET cou Page l of l Jack Kelsey From: Jack Kelsey Sent: Monday, May 10, 2004 12:12 PM To: djensen@wwassociates.net Subject: Highlands 2C Lot 34 Drainage Dear Mr. Jensen, Your response regarding the drainage system capacity was appreciated. From your comments I believe your heading in the right direction, but I felt some clarification might be helpful. From my own check I was already certain that the system would have capacity for the 10-year storm, which is the minimum criteria. In addition to this criteria, the VDOT Drainage Design Manual provides that the designer is responsible to conduct a "risk evaluation" to adjacent property and public safety. Please refer to the section of the County Design Standards Manual inserted below. In this case the property adjacent to the system and the future residential dwelling will be immediate below this system and there is potential risk that the property and dwelling may be damaged as a result of storms exceeding the 10-year storm. The third comment in my 6 May 2004 email provides you (the designer responsible for the system) the option of increasing the design storm, assuring a the future grading of the lot to assure safe & adequate overland flow, or any other option you deem appropriate as the professional certifying the design. Please contact me if you have any questions. Sincerely, Jack M. Kelsey, PE Chief of Engineering Design Standards Manual Sect 505 Stormwater Collection& Conveyance B. General Design Criteria 2. Risk Evaluation The design storm frequencies, required by the VDOT Drainage Manual, are the minimum criteria for the ideal or typical situations. However, design storm frequencies should be increased by the designer where warranted based on the "risk evaluation" of specific situations. If it is deemed necessary to protect public safety and property, the design storm frequency may also be increased by the county engineer. The VDOT Drainage Manual (6.3.1 and 14.3.2) provides that a "risk evaluation" should consider the potential for: • Damage to adjacent property • Damage to roadway or public property • Traffic interruption • Hazard to public safety • Damage to stream and floodplain environment • Emergency Access 5/10/2004 Page 1 of 1 Jack Kelsey From: Musxit@aol.com Sent: Monday, May 10, 2004 10:15 AM To: jkelsey@albemarle.org Cc: djensen@wwassociates.net; wwilkerson@albemarle.org; bmail@btrlvg.com Subject: Fwd: Highlands 2-C - Drainage design Jack-Below is the email from David Jensen, WW Associates. Consistent with this info, David will forward a revised detail that I hope will be acceptable. We need to give to the Contractor to proceed with 45 day punch list work. Thanks for your assistance. In a message dated 5/7/2004 6:13:26 PM Eastern Standard Time, djensen@wwassociates.net writes: .We can reduce the pipe slope fromDl#27 to new MH#1 to 15.75% slope as you suggest(and still clear the sanitary sewer by the clearance prescribed byACSA .Thus anchors will not be neccessary.The headwater depth @3CFS in a 12 inch diameter CMP is 1.25 feet thus, the water surface at the new endsection is2.08 feet below the invert of the exisiting 12- inch cmp therefore there are no hydraulic gradeline/backwater issues associated with the new culvert. We will calculate the hydraulic carrying capacity of the rip-rap lined channel and equate it to a storm event and report back to you. Have a good weekend. dmj Jo Higgins for Project Development Limited LC 2463 Browns Gap Tnpk Charlottesville, Va 22901 Office (434) 823 - 1224 FAX(434) 823 - 1720 Cell (434) 242 - 3080 email "musxit@aol.com" 5/10/2004 sird Jack Kelsey From: Jack Kelsey Sent: Thursday, May 06, 2004 4:36 PM To: Jo Higgins Cc: Jimmy Kesterson (Jimmy.Kesterson@VirginiaDOT.org); Warner Wilkerson Subject: Highlands 2C Lot 34 Drainage Importance: High Jo, The drainage plan & profile prepared by WW Associates and faxed 21 April 2004 has been reviewed. Based on my estimate, the Q10 for the existing 12" diameter culvert is about 2 to 3 cfs. Therefore the system proposed is adequate for the minimum capacity and is approved with the following conditions: • The channel between the outlet of the existing 12" pipe and the inlet to the new pipe must be graded to maximize the available headwater needed to overcome the entrance losses at the new end section. • The pipe slope between existing DI#27 and new manhole #1 exceeds 16% and is longer than 100 feet. Therefore pipe anchors must be installed. -Refer to the attached DDM 15 pages 7 & 8 and R&BM 104.37 documents. To clarify the application of the standards referenced above, 1 contacted Mike Viar(VDOT- Culpeper). The 16% threshold is critical for concrete pipe due to the weight of the sections and potential for slippage. Corrugated metal is lighter and more resistant to slippage therefore slippage does not become a concern until slopes are steeper and/or flows are larger. In this case with the low flow, slope of 17%, and structures at each end the anchors will not be necessary. Thank you for raising your concern about this comment. • The future dwelling to be constructed on this lot will need to be protected from stormwater flows that exceed the capacity of this drainage system. Therefore, the new lot grading will need to provide for overland release of stormwater flows that is deemed safe and adequate by the designer of the system (WW Associates). F'PF F'6F o0 DDM-15 Pgs RBS-104.pdf(95 7-8.pdf(20 KB) KB) Sincerely, Jack M. Kelsey, PE Chief of Engineering Cc: David Jensen - WW Associates (fax 1-434-582-6179) 1 Jack Kelsey From: Jack Kelsey Sent: Thursday, May 06, 2004 4:36 PM To: Jo Higgins Cc: Jimmy Kesterson (Jimmy.Kesterson@VirginiaDOT.org); Warner Wilkerson Subject: Highlands 2C Lot 34 Drainage Importance: High Jo, The drainage plan & profile prepared by WW Associates and faxed 21 April 2004 has been reviewed. Based on my estimate, the Q10 for the existing 12" diameter culvert is about 2 to 3 cfs. Therefore the system proposed is adequate for the minimum capacity and is approved with the following conditions: • The channel between the outlet of the existing 12" pipe and the inlet to the new pipe must be graded to maximize the available headwater needed to overcome the entrance losses at the new end section. • The pipe slope between existing DI#27 and new manhole #1 exceeds 16% and is longer than 100 feet. Therefore pipe anchors must be installed. Refer to the attached DDM-15 pages 7 & 8 and R&BM 104.37 documents. • The future dwelling to be constructed on this lot will need to be protected from stormwater flows that exceed the capacity of this drainage system. Therefore, the new lot grading will need to provide for overland release of stormwater flows that is deemed safe and adequate by the designer of the system (WW Associates). PD PeF PA DDM-15 Pgs RBS-104.pdf(95 7-8.pdf(20 KB) KB) Sincerely, Jack M. Kelsey, PE Chief of Engineering Cc: David Jensen - WW Associates (fax 1-434-582-6179) 4_ e W v A•Sra -4-e . vw.k. 1 or✓ �./ DDNT1 -Drainage Instructions GUIDELINES FOR MINIMUM RADII - CONCRETE PIPE MINIMUM RADIUS BASED ON 2.438 m (8 ft) PIPE JOINT LENGTH Pipe Open Joint Full Full Bevel Diameter 25% Spigot Bevel Plus Open Length Joint 25% Millimeter Inch Meter Feet Meter Feet Meter Feet 300 12 73 240 29 95 21 70 375 15 85 280 38 125 28 90 450 18 90 295 38 125 28 90 525 21 104 340 38 125 28 90 600 24 107 350 37 120 28 90 675 27 119 390 37 120 28 90 750 30 120 395 37 120 28 90 825 33 122 400 37 120 28 90 900 36 123 405 37 120 28 90 1050 42 125 410 37 120 28 90 1200 48 162 530 37 120 29 95 1350 54 154 505 37 120 31 100 1500 60 152 500 37 120 31 100 1650 66 157 515 37 120 31 100 1800 72 171 560 37 120 31 100 1950 78 174 570 37 120 31 100 2100 84 198 650 37 120 31 100 2250 90 200 655 37 120 31 100 2400 96 223 730 37 120 31 100 2700 108 187 615 37 120 31 100 DRAINAGE ON STEEP SLOPES • In situations where it is necessary to convey stormwater down a fill slope, pipe is to be used in all possible situations. • If concrete pipe is to be used, the grade of the pipe should not be steeper than 16%. If the concerns with the steep grade cannot be adequately addressed by deeper structures and/or stepping of the pipe system, concrete pipe can be used on grades steeper than 16% by use of anchor blocks. When anchor blocks are required, they should be installed at every other pipe joint as a minimum. • See Special Design Drawing No. A-73 and MA-73 for Anchor Details for Concrete Pipe. VDOT Drainage Manual 15-7 of 46 Chapter 15—Drainage Design Instructions DDM1 —Drainage Instructions • Corrugated pipe on steep slopes may be used in situations similar to those where shoulder slot inlets are used. Corrugated pipe should not be used in areas where the flow is expected to carry an abrasive bed load or that have PH and resistivity factors beyond the ranges specified in the "Allowable Types of Pipe" IIM LD-(D) 121. • See VDOT's 2001 Road and Bridge Standard PI-1, Sheet 104.37 for Anchor Details for Corrugated Pipe. • Step Down Manholes — In situations where the pipe grade needs to be more than 16%, structures at the upper end of the pipe system should be made deeper to help reduce the gradient. Additional "step down" manholes may also be added to the system to reduce the gradient. Where "step down" manholes are used, the designer should provide any needed protection to prevent erosion in the bottom of the manhole. The protection can be provided by a 1/2 inch (12 mm) steel plate in the bottom of the manhole or by providing a 3 feet (0.9 m) deep pit in the base of the manhole and filling the pit with Class I Dry Rip Rap. This protection may be needed if: 1. The flow drops more than about 4 feet (1.2 m) OR 2. The flow is expected to carry any abrasive material. OR 3. Continuous live flow or live flow lasting several days may be expected. OR 4. The size of the pipes carrying the flow requires a manhole base unit greater than 48 inches (1200 mm). • Velocity dissipation is usually needed at the outlet of pipes on steep grades and the Drainage Designer should provide the type of dissipation appropriate for velocity, pipe size, discharge and site constraints! PIPE PLUGGING The Drainage Designer will determine if existing culverts, storm sewers and box culverts will be utilized, removed, or abandoned (due to high fills, utility conflicts, under traffic, etc.) Any drainage facility that is abandoned and left in place shall be backfilled and plugged in accordance with VDOT's Road and Bridge Standard PP-1. These structures are to be labeled on the plans "To be abandoned". The following pay item includes furnishing and placing backfill material and plugging both ends of the drainage facility. Chapter 15—Drainage Design 15-8 of 46 VDOT Drainage Manual Instructions , 111100° 'SUNId m" x 1-0w Z Uam .a 4mO w ZW pow Z wrO 3Q� si Z 0 -a mcpc PQ a05 rcpao2 00, co �/~N7 IyrW 0-w,Dmw if7Z woo a�,wcow I >5 a�ad 00aw 0 O 3 U x x N ZW J o Z J 7 W a a w x w 0 W} 0 m _,mow - O¢O H N d m Q W a'0.'-� W a U ? 4. .oywwa N�~/IU .wor=- wz47 � .o0- pia z°0 U N im J O w .7„.4 U Z Q W S H Z OW,Z F-0 3`r N,5Z _~ 0:00.4W -4;WaQ JW7d NUU w NNa'a\O JKi7d zdzoU'11mz Wa4aNW z~ z000 ~ 7WO,NU D/7-w0 J' Ow 0ZZa=N 3w;Z NO- FO m w,,<woj uDap W1-yMZa ` MM 0 zWZoZa N"1- W O ^NUw c i_m ONU~am 7HHW^ W~QN 0V74 a W ~NNZp NS 3Nip0 Wa'w0� mQw��W prm prow a 0 r x a r 1- o m, wci_O,-U U w O m o^• � m U� ��U 0 Z ZU3m03 wNN2 aWUZZKSjZ ;:7:4:_ a �< ��a� 7$Ltj- awJ~ZmW ,N_i010-0~aV107! 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S, z W \�\�\ 1=1 Li_ Z 05 s ce I N \ 6 oz, ww w0 m � 0- 0\ 60 N . \\ \ N N \o\ \\\ \\\\ p w s. > zz Vi. ,w Q �\ Y N �,, ZNU NI 1w- w *' 4000 0 Z �� I Z W r W LI W N 0 n a 3 v 0 I, ! w kR N t Pagel of l S c E /fTT4 El) R C ti S'6 \✓ STS vL Steven Snell From: Steven Snell Sent: Monday, April 05, 2004 7:04 PM To: Jo Higgins Cc: Warner Wilkerson; 'Kesterson, Jimmy' Subject: Highlands 2C SR 240 drainage Jo, I received your fax today for the SR 240 drainage through Highland 2C. I will forward this to VDOT for approval. A few items that really stick out for me. 1. We will need drainage computations and a drainage area map to assure this system is working correctly. 2. I realistically don't see the end section at the beginning of the system working. I believe a drop inlet is needed. Please change or supply spread computation to show the water will make a 90 degree turn into the endsection. 10 year spread computations are needed with a 100 year overland flow shown to avoid property damage. Looks like overland flow will disrupt building site for lot 34. Thank You, Steve Snell 4/26/2004 Wednesday, April 21, 2004 9.44 AM Jo Higgins 1-434-823- 1720 p.01 PROJECT DEVELOPMENT LIMITED LC 2463 Browns Gap Turnpike, Charlottesville VA 22901 (434) 823 — 1224 Fax (434) 823 — 1720 Fax Transmittal DATE: 21 April 2004 To: Steve Snell From; Jo Higgins RE: Highlands 2C - Rockbridge Steve: At the time of our pre-inspection, there was erosion occurring across Lot 34. Based upon the field conditions, this water flows over the ground (where erosion is occurring), over the curb, into the gutter and then Into drop inlet#27. Therefore, the flow is already included in the storm water drainage system. It was recognized that to correct the erosion fully and to accommodate a building on Lot 34, the flow needed to be redirected underground and carried into drop inlet #27. Attached is a redo of the addition to the storm water system at Lot 34. It has been revised to more closely follow the path of the existing ditch coming from the culvert under RT240. Based upon the actual path of flow (see arrows), there is only a slight change in the path of flow where the pipe will pick it up and this area will be graded appropriately. In the event there was ever a severe situation, the overflow would go down the lot line between Lot 34 and Lot 35 and should not affect the building lots anyway. You mentioned a need to review drainage calculations to make sure the system can handle the flow. The pipe under RT240 Is 12" CMP, this extension is 12" CMP and the flow goes into the same drop inlet that serves this same drainage area. Therefore, this is to ask that you review this addition and approve based upon this being a minor change to the design as a corrective measure not requiring any more analysis so we can more forward with the installation. PLEASE ADVISE AS SOON AS POSSIBLE SO WE CAN RELEASE THE CONTACTOR TO DO THE WORK. (This will also need to be added to the as-builts before final.) OTHER: I met with Charles Baber who marked the guardrail location, this should be installed by the end of next week at the latest, You should already have the as-built submittal. THIS IS TO REQUEST A 45 DAY FINAL INSPECTION THE FIRST WEEK OF MAY. Based upon that inspection, we will work diligently to complete all items for final road acceptance. Please advise. Thanks Cc: John Nunley— RJR, LC Fax to 817 -- 5818 David Jensen —WW Associates Fax to 1 —434 -- 582 —6179 Charles Baber—VDOT 979 - 3759 Wednesday, April 21, 2004 9:44 AM Jo Higgins 1-434-823-1720 p,02 / 1 / - / -; 1 - i " / w J `" BE a / c441 a 'N.,. 7 / / / /, - E / / < _c-fiIf yam, W� a / , oW ■ i i ■•,, ¢ / m / IQn / CVn _s W -.J#1v / • / / 0 / ■. , � ` . 1 7/$�, C: _ 24Z , / / / / mx / / / h / g r // / u ` • .. ge e k i � �, • r / i 1 lit/ // 6.,isp -, ` ' :. / / / h / /47-4.. - ,,� - • 111 ./„/"..4 A / .47 vi / / : eft / All Q ( J ! 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A :_ 7E• d A = 0.79 4.(144) Flow (cfs) Q := 3 Velocity (fps) V := Q V = 3.82 (if flowing full) V := 3 (if partial full) 2 Gravity (ft/sec2) g := 32.2 Velocity Head (ft) H v := V H v = 0.14 2•g Entrance Loss k e := 0.5 Entrance Head H e := k e•H v H e = 0.07 Coefficient Loss (ft) A.(12) Mannings "n" n := 0.024 Hydraulic Radius (ft) R := R = 0.25 it Pipe Length (ft) L := 53 Pipe Slope (ft/ft) S := 0.0485 i Friction Head (ft) H f 81.35 := 29.n2 • L •H v H f= 0.8 Exit Head Loss (ft) Ho := Hv Ho = 0.14 Total Head Loss (ft) H L := H e + H f+ H o H L = 1.01 Tailwater (ft) TW := .5 Headwater (ft) HW o := TW + H L HW o = 1.51 invert_out := 629.59 HWelev := invert_out+ HW o HWelev = 631.1 Inlet Control Headwater- Unsubmerged K := 0.021 Entrance Coefficient - HDS#5 Table 9 M := 1.33 Equation exponent - HDS#5 Table 9 \M HW inlet '= K'd' Ad/ Q0 5 HW inlet = 0.29 / invert_in := 632.28 Inlet elev invertin+ d + HW inlet Inlet elev = 633.07 2.12 Inlet Control Headwater -' bmerged sod c := 0.0398 Entrance Coefficient - HDS#5 Table 9 Y := 0.67 Head Loss factor- HDS#5 Table 9 I 2 HW inlet c d Qo 5 + Y - 0.5.S2 HW inlet - 1.25 \A•d invertin := 444.0Inlet elev 2.12 invert in + + HW inlet Inlet elev - 445.75