20070295 Ver 6_6.03 SCM B - Anti Floatation Block_20191220

Holding Village - North Lake STORMWATER CONTORL MEASURE W Daniel Gunter
RAP-19000 Anti -Flotation Block Calculations 12/16/2019
Input Data =>
Safety Factor.
Safety factor to use =
Concrete:
Concrete unit weight =
Riser:
Inside height of Riser =
Inside length of riser=
Inside width of riser=
Wall thickness of riser=
Base thickness of riser =
Base length of riser =
Base width of riser =
Openings:
Total Orifice Area =
OD of barrel exiting manhole =
Size of drain pipe (if present) _
Trash Rack.
Bottom Length =
Bottom Width =
Top Length =
Top Width =
Height =
Trash Rack water displacement =
Concrete Present in Riser Structure ==>
Total amount of concrete:
Base of Riser =
Riser Walls =
Adjust for openings:
Opening for Orifices =
Opening for barrel =
Opening for drain pipe =
Total Concrete present, adjusted for openings =
Weight of concrete present =
1.15 (recommend 1.15 or higher)
142.0 PCF
7.00 feet
5.00 feet
5.00 feet
6.00 inches
6.00 inches
6.00 feet
6.00 feet
5.745 SF
44.00 inches
6.0 inches
8.40 feet
8.40 feet
2.10 feet
2.10 feet
2.00 feet
61.74 CF
18.00 CF
77.00 CF
2.87 CF
5.28 CF
0.10 CF
86.750 CF
12,318 lbs
Note: NC Products lists unit wt. of
manhole concrete at 142 PCF.

Holding Village - North Lake STORMWATER CONTORL MEASURE W Daniel Gunter
RAP-19000 Anti -Flotation Block Calculations 12/16/2019
Amount of water displaced by Riser Structure ==>
Displacement by concrete =
86.75 CF
Displacement by open air in riser=
175.00 CF
Displacement by trash rack =
61.74 CF
Total water displaced by riser/barrel structure =
323.49 CF
Weight of water displaced =
20,186 lbs
Calculate size of base for riser assembly ==>
Length = 9.00 feet
Width = 9.00 feet
Thickness = 24 inches
Concrete Present = 162.00 CF
Check validity of base as designed ==>
Total Water Displaced = 467.49 CF
Total Concrete Present = 248.75 CF
Total Water Displaced = 29,171 Ibs
Total Concrete Present = 35,322 Ibs
Actual safety factor = 1.21 OK
Results of design ==>
Base length =
9.00 feet
Base width =
9.00 feet
Base Thickness =
24.00 inches
CY of concrete total in base =
6.00 CY
Concrete unit weight in added base >=
142.0 PCF

Holding Village - North Lake STORMWATER CONTORL MEASURE W Daniel Gunter
RAP-19000 Anti -Flotation Block Calculations 12/16/2019
II. CALCULATION FOR RISER ANTI -FLOTATION STEEL
Input Data =>
Anti -Floatation Block Length = 9.0 feet
Anti -Floatation Block Width = 9.0 feet
Anti -Floatation Block Thickness= 24 inches
Asteel to ^concrete Ratio = 0.0020 (recommend 0.0018 or higher)
Cross -Section Calculations==>
Cross -Section Area* = 18.00 SF
Minimum Steel Area Required = 0.036 SF
5.18 SI
*Note: Assumes a "square"x-sec (L and W same)
Rebar Calculations ��>
Bar Size
4
5
6
7
8
Diameter (inches)
0.500
0.625
0.750
0.875
1.000
X-Sec Area (SI)
0.196
0.307
0.442
0.601
0.785
Minimum Number of Bars Each X-Sec
27
17
12
9
7