SW4191202_Energy Diss Calcs_1/20/2020

Appendices
25
5
0
NEW YORK DOT DISSIPATOR METHOD
FOR USE IN DEFINED CHANNELS
(Source: `Bank and channel lining procedures", New York Department of
Transportation, Division of Design and Construction, 1971.)
NOTE: To use the following chart you must know:
(1) Q full capacity
(2) Q,Q
(3) V full
(4) V10
where Q = discharge in cfs and V = Velocity in FPS.
ESTIMATION OF STONE SIZE AND DIMENSIONS FOR
CULVERT APRONS
Step 1) Compute flow velocityV at culvert or paved channel outlet.
Step 2) For pipe culverts D❑ is diameter.
For pipe arch, arch and box culverts, and paved channel outlets,
D - A where A. = cross -sectional area of flow at outlet.
❑ v
For multiple culverts, use Do = 1.25 x Do of single culvert.
Step 3) For apron grades of 10% or steeper, use recommendations
For next higher zone. (Zones 1 through 6).
rr�[
ron
�t
�11..'�i�7i�14M
�rnc
m
R
0' 5' 10, 15' 20, 25'
DIAMETER (Ft.)
Figure 8.06c
Rev. 12/93 8.06.5

2
p
APRON MATERIAL
LENGTH OF APRON
TO PROTECT
CULVERT
L1
TO PREVENT SCOUR
HOLE USE L2 ALWAYS
L2
1
STONE FILLING (FINE) CL. A
3 X DQ
4 x D,
2
STONE FILLING (LIGHT) CL. B
3 X Do
6 x D.
3
STONE FILLING (MEDIUM) CL. 1
4 X Do
8 x D,
4
STONE FILLING (HEAVY) CL. 1
4 X Do
8 x D,
5
STONE FILLING (HEAVY) CL. 2
5 x Do
14 x D,
6
STONE FILLING (HEAVY) CL. 2
6 X Do
10 x D,
l SPECIAL STUDY REQUIRED (ENERGY DISSIPATORS, STILLING
BASIN OR LARGER SIZE STONE).
Figure 8.06d
Width = 3 times pipe dia. (min.)
DETERMINATION OF STONE SIZES FOR DUMPED STONE
CHANNEL LININGS AND REVETMENTS
Step 1. Use figure 8.06.b.3 to determine maximum stone size (e.g. for 12
Fps = 20" or 550 lbs.
Step 2. Use figure 8.06.b.4 to determine acceptable size range for stone
(for 12 FPS it is 125-500 lbs. for 75% of stone, and the maximum
and minimum range in weight should be 25-500 lbs.).
NOTE: In determining channel velocities for stone linings and revetment,
use the following coefficients of roughness:
Diameter Manning's Min. thickness
(inches) .4e of lining (inches)
Fine
3
0.031
Light
6
0.035
Medium
13
0.040
Heavy
23
0.044
8.06.6
9
12
12
18
18
24
30
36
(Channels)
(Dissapators)
Items. 12193