SW6230806_Design Calculations_20240131 (3)

Riprap Velocity Dissipator Pads DATE
DEC.,2023
rJ PROJECT NAME
Brookwood Subdivision-Phase 4 TSB-18.01
LOCATION PROJECT NO
BY
r -�NC Moore County,North Carolina TDB
CHECKED BY
PAP
STORM DESIGN: 25 Year
BACKGROUND: Use the E&S Control Planning&Design Manual,Section 8.06.
REFERENCE: (NCDEHNR, 1993)
Dissipator Pipe Size(D-o) Apron Calculated Max Stone Diameter Apron Thickness
Pad FES No. Flow d-50 Length 3*D-o Width
Inches FeetFeet Inches Feet Inches
1 PH4-FES-03 18 in. 1.50 ft. 5.60 cfs 0.4 ft. 9 ft. 4.50 ft. 10.50 ft. 0.60 ft. 7 in. 0.90 ft. 11 in.
2 PH4-FES-06 18 in. 1.50 ft. 6.34 cfs 0.4 ft. 9 ft. 4.50 ft. 10.50 ft. 0.60 ft. 7 in. 0.90 ft. 11 in.
3 PH4-FES-08 30 in. 2.50 ft. 30.75 cfs 0.5 ft. 16 ft. 7.50 ft. 18.50 ft. 0.75 ft. 9 in. 1.13 ft. 14 in.
4 PH4-FES-10 48 in. 4.00 ft. 232.70 cfs 1.6 ft. 26 ft. 12.00 ft. 30.00 ft. 2.40 ft. 29 in. 3.60 ft. 43 in.
5 POND 4 FES 15 in. 1.25 ft. 6.11 cfs 0.3 ft. 8 ft. 3.75 ft. 9.25 ft. 0.45 ft. 5 in. 0.68 ft. 8 in.
Apron Construction Dimensions Riprap TERMINOLOGY:
Pad Length Width 3`D-o Thick Class
1 9 ft. 11 ft. 5 ft. 18in. B Q25= 25-Year Design Storm,Peak Discharge,(cfs)
2 9 ft. 11 ft. 5 ft. 18in. B D-o= Pipe Diameter,(in.&ft.)
3 16 ft. 19 ft. 8 ft. 18in. 1 d-50= Mean Stone Diameter of Rip-Rap,(ft.)
4 26 ft. 30 ft. 12 ft. 36in. 2 L-a= Length of Rip-Rap Apron,(ft.)
5 8 ft. 10 ft. 4 ft. 12in. A 3*D-o= Width of Rip-Rap Apron @ Pipe Outlet,(ft.)
6 W= Width of Rip-Rap Apron @ End of Apron,(ft.)
7 d-max= Maximum Stone Diameter of Rip-Rap,(ft.&in.)
8 Thickness= Thickness of Rip-Rap Apron With Filter Fabric,(ft.&in.)
9
10