HomeMy WebLinkAboutSW3200102_Custom Plastics Phase 1 Building Expansion Storm Water Calcs (12-01-2020)_20201207
Project No: 17-18-092 Sheet No: of
Date:01/11/2019
Calcs Performed By: MB
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Skimmer Sediment Basins
OBJECTIVE:
Design temporary sediment control measures to contain 10-year peak runoff. The
sediment control measures shall be designed per the North Carolina Erosion and
Sediment Control Design Manual.
THEORY/DESIGN CONSIDERATIONS:
Design skimmer sediment trapsthat will be used during each phase of the proposed
building expansion. For Phase I, evaluate the exiting basin to the southeast of the
proposed expansion. For Phase II, evaluate the use of the proposed sand filter BMP
prior to conversion.
REFERENCES:
1. North Carolina Erosion and Sediment Control Manual, 2017.
2. “Proposed Phase I and Phase II Erosion Control Plan; Custom Plastics Phase I
Building Expansion,” by Amicus Partners, PLLC, 11/01/2019.
TERMS:
3
Q= 10-year peak flow, (ft/s)
10
3
Q = minimum flow through principal spillway, (ft/s)
P
3
Q = minimum flow through emergency spillway, (ft/s)
e
cfs = cubic feet per second
C = runoff coefficient
i = rainfall intensity, (in/hr)
A = drainage area, (acres)
GIVEN/REQUIREMENTS:
Minimum design storm = 10-year \[Ref: 1\]
CALCULATIONS FOR EXISTING BASIN (PHASE I)
1. Basin Dimensions
Exterior embankment side slope = 2:1 >2:1 therefore ok. \[Ref: 2\]
Interior embankment side slope =3:1 > 2:1 therefore ok. \[Ref: 2\]
Length to width ratio = 2:1 therefore ok. \[Ref: 1\]
Spillway side slope = 4:1
Top width of embankment = 8 ft therefore ok. \[Ref: 1\]
2. Determine peak flow for basin drainage area
-Use rational method to determine peak flow based on conservatism and
drainage area being less than 200 acres \[Ref: 1\]
a. Determine time of concentration
-t = 5 minutes
c
- conservative assumption
Project No: 17-18-092 Sheet No: of
Date:01/11/2019
Calcs Performed By: MB
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Skimmer Sediment Basins
b. Determine rainfall intensity based on t. \[Ref: 1, Table 8.03.c\]
c
-i = 7.26inches/hour
c. Determine runoff coefficient, C
-Total drainage area = 2.46 acres
-Weighted runoff coefficient, C = 0.60 \[Ref: 1, Table 8.03b\]
d. Determine 10-year peak flow
QCiA
10
Q(0.60)(7.26/)(2.46)10.72 inhracrescfs
10
3. Determine Basin Volume
Volume for Skimmer Sediment Basin SB-1
23
Elevation (ft) Area (ft) Height (ft) Volume (ft)
\[Ref: 2\] \[Ref: 2\] Cumulative
802 4,613
14,255
801 3,897
17,823
800 3,239
110,761
799 2,636
113,125
798 2,091
3
a. Total basin volume = 13,125 ft
b. Determine required basin volume
3
- Minimum required basin volume = 1,800 ft/acre \[Ref: 1\]
-33
Total volume required = (1,800 ft/acre)(2.46 acres) = 4,428 ft
3 3
-4,428ft< 13,125 ft therefore ok.
c. Determine minimum surface area of skimmer sediment trap based on drainage
area
-Minimum surface area = (325 sq. ft.) x (Q) \[Ref: 1\]
10
-(325 sq. ft.) x (10.72 cfs) =3,484sq. ft.
-4,613sq. ft. > 3,484 sq. ft. therefore ok.
Project No: 17-18-092 Sheet No: of
Date:01/11/2019
Calcs Performed By: MB
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Skimmer Sediment Basins
4. Checkemergency spillway
a. Determine required capacity for emergency spillway
- Q = Q = 10.72 cfs \[Ref: 1\]
e10
-Elevation of emergency spillway = 802.0 ft
-Length of spillway = 15 ft \[Ref: 2\]
-Depth of emergency spillway = 2.0 ft
- Stage = 0.69 ft < 1.0 ft therefore ok. \[Ref: 1, Table 8.07c\]
5. Design Skimmer for required water storage volume
3
a. Required water storage volume = 4,428 ft
b. Desired dewatering time = 2 days
c. A 2.0-inch skimmer is required \[Ref: 3\]
d. A 0.8-inch orifice radius is required \[Ref: 3\]
e. A 1.6-inch orifice diameter is required
CALCULATIONS FOR SKIMMER SEDIMENT BASIN SB-2(PHASE II)
1. Basin Dimensions
Exterior embankment side slope = 3:1 >2:1 therefore ok. \[Ref: 2\]
Interior embankment side slope =3:1 > 2:1 therefore ok. \[Ref: 2\]
Length to width ratio = 2:1 therefore ok. \[Ref: 1\]
Spillway side slope = 4:1
Top width of embankment = 8 ft therefore ok. \[Ref: 1\]
2. Determine peak flow for basin drainage area
- Use rational method to determine peak flow based on conservatism and
drainage area being less than 200 acres \[Ref: 1\]
a. Determine time of concentration
- t = 5 minutes
c
- conservative assumption
b. Determine rainfall intensity based on t. \[Ref: 1, Table 8.03.c\]
c
-i = 7.26inches/hour
c. Determine runoff coefficient, C
-Total drainage area = 4.33 acres
-Weighted runoff coefficient, C = 0.66\[Ref: 1, Table 8.03b\]
o Heavy Industrial Assumed
d. Determine 10-year peak flow
QCiA
10
Q(0.66)(7.26/)(4.33)20.75 inhracrescfs
10
Project No: 17-18-092 Sheet No: of
Date:01/11/2019
Calcs Performed By: MB
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Skimmer Sediment Basins
3. Determine Basin Volume
Volume for Sediment Basin SB-2
23
Elevation (ft) Area (ft) Height (ft)Volume (ft)
\[Ref: 2\] \[Ref: 2\]
810 898
12,011
811 3,124
15,776
812 4,407
110,853
813 5,746
117,297
814 7,142
3
a. Total basin volume = 17,297 ft
b. Determine required basin volume
3
- Minimum required basin volume = 1,800 ft/acre \[Ref: 1\]
-33
Total volume required = (1,800 ft/acre)(4.33 acres) = 7,794 ft
3 3
-7,794ft< 17,297 ft therefore ok.
c. Determine minimum surface area of skimmer sediment trap based on drainage
area
- Minimum surface area = (325 sq. ft.) x (Q) \[Ref: 1\]
10
-(325 sq. ft.) x (20.75 cfs) =6,744 sq. ft.
-6,744sq. ft. < 7,142 sq. ft. therefore ok.
4. Checkemergency spillway
a. Determine required capacity for emergency spillway
-Q = Q = 20.75 cfs \[Ref: 1\]
e10
-Elevation of emergency spillway = 813.0 ft
-Length of spillway = 12 ft \[Ref: 2\]
-Depth of emergency spillway = 1.0 ft
- Stage = 0.81 ft < 1.0 ft therefore ok. \[Ref: 1, Table 8.07c\]
5. Design Skimmer for required water storage volume
3
a. Required water storage volume = 7,794 ft
b. Desired dewatering time = 2 days
c. A 2.5-inch skimmer is required \[Ref: 3\]
d. A 1.0-inch orifice radius is required \[Ref: 3\]
e. A 2.0-inch orifice diameter is required
Project No:17-18-092 Sheet No: 1 of
Date:08/28/2020
Calcs Performed By:CMM
Calcs Checked By:NRP
Project Name: Custom Plastics Phase I Building Expansion
Subject: Pipe Hydraulics and Grate Capacity
OBJECTIVE:
Design a series of storm drainage pipes to adequately convey runoff during and after
construction. Verify the grate capacity of all catch basins and drop inlets.
REFERENCES:
1.North Carolina Erosion and Sediment Control Manual, 2018
2.“Stormwater Management Plan,” by Amicus Partners PLLC, 08/28/2020.
3. Hydraulic Toolbox
4. “Water Resources Engineering,” by Mays, Larry W., 2001.
5. NCDOT Roadway Standards
TERMS:
3
Q= 10-year peak flow, (ft/s)
10
3
Q= inlet capacity, (ft/s)
i
C = runoff coefficient
C = orifice coefficient
0
d = depth of water ponded over grate, (ft)
2
g = acceleration due to gravity, (ft/s)
i = rainfall intensity, (in/hr)
A = drainage area, (acres)
2
a = clear opening area of a grate, (ft)
t = time of concentration, (min)
c
GIVEN/REQUIREMENTS:
Minimum design storm = 10-year\[Ref: 1\]
Project No:17-18-092 Sheet No: 2 of
Date:08/28/2020
Calcs Performed By:CMM
Calcs Checked By:NRP
Project Name: Custom Plastics Phase I Building Expansion
Subject: Pipe Hydraulics and Grate Capacity
CALCULATIONS:
1. Determine grate capacity for catch basins and drop inlets
a. Determine maximum inflow for 10-yr storm for drop inlets and catch basins
Catch Total Drainage 10-yr Rainfall Weighted Runoff 10-yr
Basin/Area (Acres), AIntensity, i, (in/hr)Coefficient, CFlow, Q
10
Inlet\[Ref: 2\] \[Ref: 1, \[Ref: 1, (cfs)
a
Table 8.03.10\]Table 8.03a\]
DI10.567.260.301.22
DI2 0.217.26 0.751.14
DI40.447.260.902.87
Conservative estimate based on minimum time of concentration = 5 min.
b.Determine grate capacity for inlets
-Since inletsare in sag locations, assume orifice control and 50% clogging by
debris. The maximum ponding depth will be evaluated as 0.5 –foot.
0.5
- \[Ref: 4, Eq. 16.1.33\]
QCAgd(2)
i 0
-Opening ratio = 0.46 \[Ref: 5, NCDOT 840.03\]
-C= 0.67 \[Ref: 4\]
0
-Grate capacity for aforementioned structures
0.5
23
Q 0.670.466.(2)32.20.510.49 sqftftsftfts
i
o
33
50%0.5010.495.25 Qftsfts
i
o The grate capacity far exceeds the calculated ten-yearflow
Project No:17-18-092 Sheet No: 3 of
Date:08/28/2020
Calcs Performed By:CMM
Calcs Checked By:NRP
Project Name: Custom Plastics Phase I Building Expansion
Subject: Pipe Hydraulics and Grate Capacity
2.Determine pipe sizes for pipes P1 –P8
\[Ref: 3\]
DrainContributingFlow,
Pipe Drainage areasQ
\[Ref:2\](cfs)
P1DI11.22
EX. P2DI1, EX. P22.88
P3DI1, EX. P2, DI24.02
P4A DI1, EX. P2, DI24.02
P4BDI1, EX. P2, DI24.02
P5DI1, EX. P2, DI2, SF1 7.62
EX. P6 DI1, EX. P2, DI2, SF1, 10.02
TD2
P7DI42.87
P8DI42.87
DrainFlow, Slope, SManning’s Required Actual Velocity
a
PipeQ(ft/ft) Coefficient, C Diameter (in) Diameter(ft/s)
(cfs) \[Ref:2\] \[Ref: 3\] (in)\[Ref: 3\]
P1 1.220.0300.0151515 5.40
EX. P2 2.880.0050.0152424 3.48
P3 4.020.0070.0152424 4.32
P4A 4.020.0070.0152424 4.00
P4B4.020.0200.0152424 6.29
P5 7.620.0070.0152424 5.13
EX. P610.020.0060.015(2) 15(2) 155.05
P7 2.870.0100.0151515 4.59
P8 2.870.0480.0151515 8.16
Hydraulic Analysis Report
Project Data
Project Title: Custom Plastics
Designer:
Project Date: Friday, September 04, 2020
Project Units: U.S. Customary Units
Notes:
Channel Analysis: Pipe P1
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 1.2500 ft
Longitudinal Slope: 0.0300 ft/ft
Manning's n: 0.0150
Flow: 1.2200 cfs
Result Parameters
Depth: 0.2994 ft
Area of Flow: 0.2259 ft^2
Wetted Perimeter: 1.2786 ft
Hydraulic Radius: 0.1766 ft
Average Velocity: 5.4018 ft/s
Top Width: 1.0670 ft
Froude Number: 2.0691
Critical Depth: 0.4355 ft
Critical Velocity: 3.2073 ft/s
Critical Slope: 0.0070 ft/ft
Critical Top Width: 1.19 ft
Calculated Max Shear Stress: 0.5605 lb/ft^2
Calculated Avg Shear Stress: 0.3307 lb/ft^2
Channel Analysis: Ex. Pipe P2
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 2.0000 ft
Longitudinal Slope: 0.0050 ft/ft
Manning's n: 0.0150
Flow: 2.8800 cfs
Result Parameters
Depth: 0.6186 ft
Area of Flow: 0.8269 ft^2
Wetted Perimeter: 2.3590 ft
Hydraulic Radius: 0.3505 ft
Average Velocity: 3.4829 ft/s
Top Width: 1.8488 ft
Froude Number: 0.9178
Critical Depth: 0.5918 ft
Critical Velocity: 3.7034 ft/s
Critical Slope: 0.0059 ft/ft
Critical Top Width: 1.83 ft
Calculated Max Shear Stress: 0.1930 lb/ft^2
Calculated Avg Shear Stress: 0.1094 lb/ft^2
Channel Analysis: Pipe P3
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 2.0000 ft
Longitudinal Slope: 0.0070 ft/ft
Manning's n: 0.0150
Flow: 4.0200 cfs
Result Parameters
Depth: 0.6744 ft
Area of Flow: 0.9314 ft^2
Wetted Perimeter: 2.4784 ft
Hydraulic Radius: 0.3758 ft
Average Velocity: 4.3163 ft/s
Top Width: 1.8910 ft
Froude Number: 1.0839
Critical Depth: 0.7031 ft
Critical Velocity: 4.0775 ft/s
Critical Slope: 0.0060 ft/ft
Critical Top Width: 1.91 ft
Calculated Max Shear Stress: 0.2946 lb/ft^2
Calculated Avg Shear Stress: 0.1641 lb/ft^2
Channel Analysis: Pipe P4A
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 4.0200 ft
Longitudinal Slope: 0.0070 ft/ft
Manning's n: 0.0150
Flow: 4.0200 cfs
Result Parameters
Depth: 0.5360 ft
Area of Flow: 1.0060 ft^2
Wetted Perimeter: 3.0053 ft
Hydraulic Radius: 0.3348 ft
Average Velocity: 3.9959 ft/s
Top Width: 2.7331 ft
Froude Number: 1.1607
Critical Depth: 0.5781 ft
Critical Velocity: 3.5800 ft/s
Critical Slope: 0.0051 ft/ft
Critical Top Width: 2.82 ft
Calculated Max Shear Stress: 0.2341 lb/ft^2
Calculated Avg Shear Stress: 0.1462 lb/ft^2
Channel Analysis: Pipe P4B
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 2.0000 ft
Longitudinal Slope: 0.0200 ft/ft
Manning's n: 0.0150
Flow: 4.0200 cfs
Result Parameters
Depth: 0.5146 ft
Area of Flow: 0.6395 ft^2
Wetted Perimeter: 2.1279 ft
Hydraulic Radius: 0.3006 ft
Average Velocity: 6.2858 ft/s
Top Width: 1.7485 ft
Froude Number: 1.8316
Critical Depth: 0.7031 ft
Critical Velocity: 4.0775 ft/s
Critical Slope: 0.0060 ft/ft
Critical Top Width: 1.91 ft
Calculated Max Shear Stress: 0.6422 lb/ft^2
Calculated Avg Shear Stress: 0.3751 lb/ft^2
Channel Analysis: Pipe P5
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 2.0000 ft
Longitudinal Slope: 0.0070 ft/ft
Manning's n: 0.0150
Flow: 7.6200 cfs
Result Parameters
Depth: 0.9580 ft
Area of Flow: 1.4867 ft^2
Wetted Perimeter: 3.0575 ft
Hydraulic Radius: 0.4863 ft
Average Velocity: 5.1253 ft/s
Top Width: 1.9982 ft
Froude Number: 1.0471
Critical Depth: 0.9814 ft
Critical Velocity: 4.9684 ft/s
Critical Slope: 0.0064 ft/ft
Critical Top Width: 2.00 ft
Calculated Max Shear Stress: 0.4184 lb/ft^2
Calculated Avg Shear Stress: 0.2124 lb/ft^2
Channel Analysis: Ex. Pipe P6
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 1.7700 ft
Longitudinal Slope: 0.0060 ft/ft
Manning's n: 0.0150
Flow: 10.0200 cfs
Result Parameters
Depth: 1.3300 ft
Area of Flow: 1.9834 ft^2
Wetted Perimeter: 3.7129 ft
Hydraulic Radius: 0.5342 ft
Average Velocity: 5.0520 ft/s
Top Width: 1.5299 ft
Froude Number: 0.7819
Critical Depth: 1.1754 ft
Critical Velocity: 5.7755 ft/s
Critical Slope: 0.0082 ft/ft
Critical Top Width: 1.67 ft
Calculated Max Shear Stress: 0.4980 lb/ft^2
Calculated Avg Shear Stress: 0.2000 lb/ft^2
Channel Analysis: Pipe P7
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 1.2500 ft
Longitudinal Slope: 0.0100 ft/ft
Manning's n: 0.0150
Flow: 2.8700 cfs
Result Parameters
Depth: 0.6343 ft
Area of Flow: 0.6252 ft^2
Wetted Perimeter: 1.9820 ft
Hydraulic Radius: 0.3154 ft
Average Velocity: 4.5907 ft/s
Top Width: 1.2499 ft
Froude Number: 1.1439
Critical Depth: 0.6805 ft
Critical Velocity: 4.2025 ft/s
Critical Slope: 0.0079 ft/ft
Critical Top Width: 1.25 ft
Calculated Max Shear Stress: 0.3958 lb/ft^2
Calculated Avg Shear Stress: 0.1968 lb/ft^2
Hydraulic Analysis Report
Project Data
Project Title: Custom Plastics
Designer:
Project Date: Friday, September 04, 2020
Project Units: U.S. Customary Units
Notes:
Channel Analysis: Pipe P1
Notes:
Input Parameters
Channel Type: Circular
Pipe Diameter: 1.2500 ft
Longitudinal Slope: 0.0300 ft/ft
Manning's n: 0.0150
Flow: 1.2200 cfs
Result Parameters
Depth: 0.2994 ft
Area of Flow: 0.2259 ft^2
Wetted Perimeter: 1.2786 ft
Hydraulic Radius: 0.1766 ft
Average Velocity: 5.4018 ft/s
Top Width: 1.0670 ft
Froude Number: 2.0691
Critical Depth: 0.4355 ft
Critical Velocity: 3.2073 ft/s
Critical Slope: 0.0070 ft/ft
Critical Top Width: 1.19 ft
Calculated Max Shear Stress: 0.5605 lb/ft^2
Calculated Avg Shear Stress: 0.3307 lb/ft^2
Project No: 17-18-092 Sheet No: 1 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Open Channel Hydraulics
OBJECTIVE:
Design ditchline(s) to adequately convey runoff from various drainage basins.
REFERENCES:
1. NCDEQ Erosion Control Manual, 2017.
2. “Storm Water Management Plan,” by Amicus Partners,PLLC, 01/11/2019.
3. Erosion Control Materials Design Software, Ver. 5.0, by North American Green.
4. “Pipe Hydraulics and Grate Capacity,” by Amicus Partners, PLLC, 01/11/2019.
TERMS:
3
Q= 10-year peak flow, (ft/s)
10
3
Q = inlet capacity, (ft/s)
i
C = runoff coefficient
i = rainfall intensity, (in/hr)
A = drainage area, (acres)
t = time of concentration, (min)
c
GIVEN/REQUIREMENTS:
Minimum design storm = 10-year\[Ref: 1\]
CHANNEL TD1:
a. Determine time of concentration
- t = 5 minutes
c
- conservative assumption
b. Determine rainfall intensity based on t. \[Ref: 1, Table 8.03.c\]
c
-i = 7.26inches/hour
c. Determine runoff coefficient, C
-Total drainage area = 0.56 acres
-Weighted runoff coefficient, C = 0.30 \[Ref: 1, Table 8.03b\]
d. Determine 10-year peak flow
QCiA
10
Q(0.30)(7.26/)(0.56)1.22 inhracrescfs
10
See attached print outs for velocity and safety factor for shear stress
Project No: 17-18-092 Sheet No: 2 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Open Channel Hydraulics
CHANNEL TD2:
a. Determine time of concentration
- t = 5 minutes
c
- conservative assumption
b. Determine rainfall intensity based on t
. \[Ref: 1, Table 8.03.c\]
c
i = 7.26 inches/hour
c. Total flow = 9.25 cfs \[Ref: 4\]
See attached print outs for velocity and safety factor for shear stress
Project No:17-18-092 Sheet No: 1 of
Date:08/28/2020
Calcs Performed By:CMM
Calcs Checked By:NRP
Project Name: Custom Plastics Phase I Building Expansion
Subject: Sand Filtration System
OBJECTIVE:
Design a proposed sand filtration systemto treat the required water quality volume
and provide necessary volume control
DESIGN CONSIDERATIONS:
The following design is for a singlesand filtration and sediment forebay facility
designed to treat the 1st-inchof runoff.
REFERENCES:
1.“NCDEQ Storm Water BMP Manual,” Revised 2017.
2. “Stormwater Management PLan,” by Amicus Partners, PLLC, 08/28/2020.
3. NCDEQ Erosion and Sediment Control Manual, 2017.
4. “Hydrologic Evaluation,” by Amicus Partners, PLLC, 08/28/2020.
5. FHWA Urban Drainage Design Program, HY-22.
TERMS:
3
D= design volume, (ft)
v
3
DD= discounted design volume, (ft)
v
I = Impervious fraction, (unitless)
A = drainage area, (acres)
R = Volumetric runoff coefficient,(unitless)
v
R = design storm depth, (inches)
d
2
A = surface area of the sand filter bed, (ft)
f
d = Depth of the sand filter bed, (ft)
F
k = coefficient of permeability for the sand filter bed, (ft/day)
t = time required to draw down the WQV through the sand filter bed, (day)
h= depthof water above filter bedfor design volume(ft)
f
Qm = media capacity, (cfs)
Qd = underdrain design flow,(cfs)
n= roughness factor, (unitless)
S = underdrain slope, (ft/ft)
D = requireddiameter of underdrain pipe, (inches)
Project No:17-18-092 Sheet No: 2 of
Date:08/28/2020
Calcs Performed By:CMM
Calcs Checked By:NRP
Project Name: Custom Plastics Phase I Building Expansion
Subject: Sand Filtration System
GIVEN/REQUIREMENTSFOR SAND FILTERS:\[Ref: 1\]
1. Design Requirements for Sand Filters
a. The volume of water that can be stored in the sediment chamber and the sand
chamber above the sand surface combinedshall be 0.75 times the treatment
volume.
st
b. Sand Filters shall be sized to treat the 1-inch of runoff.
c. The sand filtration systems shall meet or exceed 85% removal efficiency of Total
Suspended Solids (TSS).
d. The minimum separation between the lowest point of the sand filter system and
SHWT shall be 2-feet for open-bottomdesigns.
e.If the sand filter is designed to attenuate peak flows, additional surface area may
be added in the sediment forebay only. The sand filter must be designed so that
50% of thetreatment volume can be stored in the sand chamber below the first
bypass device.
f. The maximum ponding depth is limited to six feet.
g. Sand media shall meet ASTM C33. The sand particles shall be less than 2 mm
average diameter.
h. The filter bed shall have a minimum depth of 18-inches. The minimum depth of
sand above the underdrain pipe shall be 12-inches.
i.The sand filter shall be maintained in a manner that results in a drawdown of at
least 2-inches per hour at the sand surface.
j.At least one clean-outpipe shall be provided at the low point of each underdrain
line.
Project No:17-18-092 Sheet No: 3 of
Date:08/28/2020
Calcs Performed By:CMM
Calcs Checked By:NRP
Project Name: Custom Plastics Phase I Building Expansion
Subject: Sand Filtration System
CALCULATIONS for SAND FILTER SF-1
1. Sand Filter SF-1 (Includes Sediment Forebay and Sand Filter)
23
Elevation (ft) Area (ft) Height (ft)Volume(ft)
\[Ref: 2\]\[Ref: 2\]
8101,250
12,667
8114,084
14,905
8125,726
1 6,576
8137,425
1 8,303
8149,180
3
a. Total volume available in SF-1 (elev. 814.00 ft) = 22,451ft
3
b. Total volume available to emergency spillway (elev. 813.00 ft) = 14,148 ft
1a. Sand Filter SF-1
23
Elevation (ft) Area (ft) Height (ft)Volume (ft)
\[Ref: 2\]\[Ref: 2\]
8101,225
1 1,634
8112,042
1 2,452
8122,863
1 3,288
8133,713
1 4.151
8144,590
3
a. Total volume available in SF-1 (elev. 814.00 ft) = 11,525ft
1b. Forebay FB-1
23
Elevation (ft) Area (ft) Height (ft)Volume (ft)
\[Ref: 2\]\[Ref: 2\]
8100
1 1,021
8112,042
1 2,453
8122,863
1 3,288
8133,713
1 4.152
8144,590
3
a. Total volume available in FB-1 (elev. 814.00 ft) = 10,914ft
Project No:17-18-092 Sheet No: 4 of
Date:08/28/2020
Calcs Performed By:CMM
Calcs Checked By:NRP
Project Name: Custom Plastics Phase I Building Expansion
Subject: Sand Filtration System
2. Compute DesignVolume (D) for area draining to SF-1
V
a. Compute Runoff Coefficient, R, using (Schueler’s Method)
V
i. I = (1.60-acres Imp.)/(2.50-acres total) = 0.64 \[Ref: 1\]
ii. R= 0.05 + 0.009(I) = 0.05+ 0.009(64) = 0.63\[Ref: 1\]
V
b. Compute Design Volume, D
V
i.D= 3,630(R)((R)(A)= 3,630(1.0)(0.63)(2.5)
V DV
3
ii.D= 5,717 ft or 0.13 ac-ft
V
33
iii.DD= 0.75D = 0.75(5,717 ft) = 4,288 ft
VV
3. Size Filtration Bed Chamber
a. Assume Max Ponding Depth of 3.5-feet
b. Minimum surface area required (A)= DDV/h\[Ref: 1\]
ff
3 2
c. A = (DD)/(h) = 4,288 ft/3.5ft=1,225ft
fVf
d. Length to Width Ratio 2:1
22
e.Use 125’x 10’ = 1,250 ft> 1.225ft
4. Compute Filter Media Capacity
i. Media Capacity = (A)(k)(h+d)/d
ffff
ii.k = 2in/hour = 0.0000463 ft/sec
2
iii. Media Capacity = (1,225ft)(0.0000463 ft/s)(3.5-ft + 1.5-ft)/(1.5 ft)
iv.Media Capacity = 0.19cfs
5. Design Inlets and Underdrain System\[Ref: 1\]
a.Apply fact or of safety of 10
Qd = 10Qm= 10(0.19cfs) = 1.9cfs
3
3
8
8
1.90.011 cfs
Qn
d
b.
D 16164.3 inches
0.5
0.5
S
0.5
c. 4.3 inches < 5.13 inches therefore use two 4”pipes.
Project No: 17-18-092 Sheet No: 1 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Concrete Spillway Design
OBJECTIVE:
Determine thickness of concrete spillway and reinforcement requirements for the riser
and foundation/anti-flotation block.
THEORY/DESIGN CONSIDERATIONS:
The riser will be considered as four separate simply supported concrete slabs
designed for the expected hydrostatic loads.
REFERENCES:
1. “Hydrologic Evaluation” by Amicus Partners, PLLC, 01/11/19.
2. “Stormwater Management Plan” by Amicus Partners, PLLC, 01/11/19.
3. American Concrete Institute – Building Code Req. for Reinforced Concrete.
4. “Reinforced Concrete – Mechanics & Design,” by McGregor, 1992.
TERMS:
H' = effective height of pressure distribution, (ft)
l = clear span for positive moment, (ft)
2
P = factored net soil pressure, (lb/ft)
H = hydrostatic load, (lb/ft)
W= factored hydrostatic load, (lb/ft)
u
W= weight of displaced water, (lb)
w
W = weight of riser, (lb)
R
W = weight of spread footing, (lb)
F
W = weight of concrete riser and footing, (lb)
c
M = Design moment, (ft-lb)
u
M = moment capacity of reinforcement, (ft-lb)
cap
2
A= area of steel, (in)
s
a = depth of rectangular stress distribution, (in)
D = depth of footing, (ft)
d = effective depth of concrete, (in)
b = width of critical section, (in)
V= allowable shear force, (kips)
u
V = shear capacity of concrete, (lb)
c
'2
f = 28-day compressive strength of concrete, (lb/in)
c
2
f = yield strength of steel, (kips/in)
y
= reduction factor
psi = pounds per square inch
plf = pounds per linear foot
psf = pounds per square foot
ksi = kips per square inch
2
A =area of footing, (ft)
F
F = factor of safety
s
Project No: 17-18-092 Sheet No: 2 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Concrete Spillway Design
GIVEN/REQUIREMENTS–RISER IN SF-1:
Exterior Dimensions of riser = 4.00-ft x 4.00-ft \[Ref: 1\]
Bottom of sand filter = 810.00 feet \[Ref: 1\]
Bottom Elevation of Riser = 808.50 feet \[Ref: 2\]
Top of Riser = 813.00 feet\[Ref: 2\]
Maximum Water Elevation = 813.39 feet\[Ref: 1\]
Diameter of Outlet Pipe = 24-inch \[Ref: 1\]
'
f = 3,500 psi
c
f = 60 ksi
y
I. RISER CALCULATIONS:
1.Determine effective depth of concrete
4.0012/ftinft
l
a. Minimum thickness = t 2.40 in\[Ref: 3, Table 9.5(a)\]
2020
b. Use a thickness of 6-inches
c. Assume #5 rebar
d. Minimum cover for reinforcement = 1.5-inches \[Ref: 3, 7.7.1\]
(Assume rebar mat will be located in middle of slab.)
5
e. dinininin 632.69
16
2.Determine factored hydrostatic load
'
a.
Hftftft 813.39808.504.89
'
lb
b. HH 62.44.89305/ftplfft
3
ft
c. WHplfplfft 1.61.6305488/\[Ref: 3, Eq. 9-6\]
u
3.Determine design moment
22
Wlplfft 4883.00
u
a. M 549/ftlbft
u
88
Project No: 17-18-092 Sheet No: 3 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Concrete Spillway Design
4.Determine flexural reinforcement based on moment capacity
2
a. Assume #5 rebar @ 12-in on center (A= 0.31 in)
s
b. Determine depth of rectangular stress distribution of slab
'
0.85 fabAf
csy
2
\[Ref: 4, Eq. 4-11\]
0.853,500120.3160,000 psiaininpsi
ain 0.52
c. Determine moment capacity of reinforcement
a
MAfd
capsy
2
1 ft
2
0.52 in
Minksiin 0.310.85602.69\[Ref: 4, Eq. 4-12b\]
cap
2
12 in
Mftlb 3,202
cap
d. 3,202 ft-lb/ft > 549 ft-lb/ft therefore ok.
5. Determine minimum reinforcement required for flexure
200122.69 inin
200 bd
2
a. A 0.11 in \[Ref: 3, Eq. 10-3\]
s(min)
f 60000 psi
y
2
b. Use #5 @ 12-in on center = 0.31 in
6. Determine minimum reinforcement required in perpendicular direction
a. Shrinkage and temperature reinforcement shall be provided in the direction
perpendicular to the flexural reinforcement.
2
b. A 0.00180.00181260.13 btininin\[Ref: 3, 7.12.2.1\]
s(min)
2
c. Use #5 @ 12-in on center = 0.31 in
Project No: 17-18-092 Sheet No: 4 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Concrete Spillway Design
7. Check for shear at the bottom of the riser
a. Determine factored shear strength
488/3.00 plfftft
Wl
u
V 1.151.15842/lbft\[Ref: 3, 8.3.3\]
u
22
b. Determine nominal shear strength of concrete \[Ref: 3, 7.12.2.1\]
'
\[Ref: 3, Eq. 11-3\]
Vfbd 223,500122.693,819/psiininlbft
nc
c. VV 0.853,819/3,247/842/lbftlbftlbft\[Ref: 3, Eq. 11-1\]
nu
therefore ok.
II. FOOTING CALCULATIONS:
1. Determine required area of footing
a. Required area of footing based on buoyancy.
b. Weight of water displaced at maximum pool elevation.
'
Hftftft 813.39808.504.89
3
Wftftftlbftlb 4.004.004.8962.44,882
w
c. Weight of riser walls
6
3
Wft 4.0023.0024.50140 ftftftlbft
R
12
6
3
(2)1403,970 ftftlbftlb
12
d. Size of footing required
AFWW()1.5(4,8823,970)1,092 lblblb
FswR
e. Use 5.0-ft by 5.0-ft by 1.0-ft foundation for riser
3
, therefore o.k.
Wftftftlbftlblb 5.05.01.01403,5001,092
F
2. Determine factored net soil pressure
a. Weight of footing
3
Wftftftlbftlb 5.05.01.01403,500
F
Project No: 17-18-092 Sheet No: 5 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Concrete Spillway Design
b.Total weight of riser and footing
WWWlblblb 3,5003,9707,470
CFR
c. Factored net soil pressure
1.77.47 k
FW
sc
P 0.51 ksf
2
Aft 25
F
3. Determine effective depth of concrete
a. Minimum cover for reinforcement = 3-inches \[Ref: 3, 7.7.1\]
b. Assume #5 rebar
c. dininin 12318
4. Check footing for one-way shear
2.52.170.67 ftftft
a. Vksfft(0.51)(5.0)0 k
u
12
'
Vfbd 2
cc
b. \[Ref: 3, Eq. 11-3\]
0.8523,50060856.8 psiinink
c. V > V therefore ok. \[Ref: 3, Eq. 11-1\]
cu
5. Check footing for two-way shear
2
d/2
2
a. Vksfftft 0.51254.003.17 k
u
12
'
Vfbd 4
cc
b. \[Ref: 4, Eq. 11-35\]
0.8543,5001608257 psiinink
c. V > V therefore ok. \[Ref: 4, Eq. 11-1\]
cu
Project No: 17-18-092 Sheet No: 6 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Concrete Spillway Design
6.Design reinforcement for footing
2
0.67 ft
a.Mksfft 0.5150.57 kft
u
2
0.5712 kftinft
M
u
A
s
a 0.52 in
fd 0.85608 ksiin
b. \[Ref: 4, Eq. 4-12b\]
y
22
2
Ain 0.02
s
c. Check minimum reinforcement requirements for temperature and shrinkage
2
A 0.00180.00186080.86 bdininin \[Ref: 3, 7.12.2.1\]
s(min)
2
d. A = 0.86in therefore use two mats of #5 at 12” on center in each direction
s
Project No: 17-18-092 Sheet No: 1 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Rip Rap Apron
OBJECTIVE:
Design Riprap Apron to dissipate the 10-year flow discharging from FES-1
REFERENCES:
1. North Carolina Erosion and Sediment Control Manual, 2017.
2. “Hydraulics & Grate Capacity Calculations,” by Amicus Partners, PLLC,
01/11/2019.
TERMS:
3
Q
= 10-year peak flow, (ft/s)
10
d= diameter of discharge pipe, (in)
o
d= median stone size in a well-graded riprap apron, (in)
50
d= maximum stone diameter in riprap apron, (in)
max
L = length of riprap apron, (ft)
a
W = downstream width of riprap apron, (ft)
cfs = cubic feet per second
Tw = Tailwater
GIVEN/REQUIREMENTS:
Minimum design storm = 10-year\[Ref: 2\]
Q= 1.22 cfs\[Ref: 2\]
10
V= 5.40 ft/s \[Ref: 2\]
10
d= 15”\[Ref: 2\]
o
CALCULATIONS:
1. Determine median and maximum stone diameter
a. Determine median stone diameter
- d= 4”\[Ref: 1, Fig. 8.06a\]
50
b. Determine maximum stone size
-d = 1.5 x d = 1.5(4”) = 6.0” \[Ref: 1\]
max50
2. Determine dimensions of riprap apron
a. Determine minimum length of riprap apron
- L = 6 ft \[Ref: 1, Fig. 8.06a\]
a
b. Determine width of riprap apron
-Upstream width = 3d= 3(1.25 ft) = 3.75 ft \[Ref: 1, Fig. 8.06a\]
o
-Downstream width of apron
o W= d+ L = 1.25 ft + 6 ft = 7.25 ft
oa
c. Determine thickness of apron
-T = 1.5(d) = 1.5(6.0”) = 9.0” \[Ref: 1\]
max
- Use T = 9.0”
- Use appropriate filter fabric underneath apron.
Project No: 17-18-092 Sheet No: 2 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Rip Rap Apron
OBJECTIVE:
Design Riprap Apron to dissipate the 10-year flow discharging from FES-2
REFERENCES:
3. North Carolina Erosion and Sediment Control Manual, 2017.
4. “Hydraulics & Grate Capacity Calculations,” by Amicus Partners, PLLC,
01/11/2019.
TERMS:
3
Q
= 10-year peak flow, (ft/s)
10
d= diameter of discharge pipe, (in)
o
d= median stone size in a well-graded riprap apron, (in)
50
d= maximum stone diameter in riprap apron, (in)
max
L = length of riprap apron, (ft)
a
W = downstream width of riprap apron, (ft)
cfs = cubic feet per second
Tw = Tailwater
GIVEN/REQUIREMENTS:
Minimum design storm = 10-year\[Ref: 2\]
Q= 6.85 cfs\[Ref: 2\]
10
V= 4.99 ft/s \[Ref: 2\]
10
d= 24”\[Ref: 2\]
o
CALCULATIONS:
3. Determine median and maximum stone diameter
a. Determine median stone diameter
- d= 4”\[Ref: 1, Fig. 8.06a\]
50
b. Determine maximum stone size
-d = 1.5 x d = 1.5(4”) = 6.0” \[Ref: 1\]
max50
4. Determine dimensions of riprap apron
a. Determine minimum length of riprap apron
- L = 9 ft \[Ref: 1, Fig. 8.06a\]
a
b. Determine width of riprap apron
-Upstream width = 3d= 3(2.0 ft) = 6.0 ft \[Ref: 1, Fig. 8.06a\]
o
-Downstream width of apron
o W= d+ L = 2.0 ft + 6 ft = 8.0 ft
oa
c. Determine thickness of apron
-T = 1.5(d) = 1.5(6.0”) = 9.0” \[Ref: 1\]
max
- Use T = 15”
- Use appropriate filter fabric underneath apron.
Project No: 17-18-092 Sheet No: 3 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Rip Rap Apron
OBJECTIVE:
Design Riprap Apron to dissipate the 10-year flow discharging from FES-3
REFERENCES:
5. North Carolina Erosion and Sediment Control Manual, 2017.
6. “Hydraulics & Grate Capacity Calculations,” by Amicus Partners, PLLC,
01/11/2019.
TERMS:
3
Q
= 10-year peak flow, (ft/s)
10
d= diameter of discharge pipe, (in)
o
d= median stone size in a well-graded riprap apron, (in)
50
d= maximum stone diameter in riprap apron, (in)
max
L = length of riprap apron, (ft)
a
W = downstream width of riprap apron, (ft)
cfs = cubic feet per second
Tw = Tailwater
GIVEN/REQUIREMENTS:
Minimum design storm = 10-year\[Ref: 2\]
Q= 9.25 cfs\[Ref: 2\]
10
V= 5.00 ft/s \[Ref: 2\]
10
d= (2) 15” so assum 30”\[Ref: 2\]
o
CALCULATIONS:
5. Determine median and maximum stone diameter
a. Determine median stone diameter
- d= 4”\[Ref: 1, Fig. 8.06a\]
50
b. Determine maximum stone size
-d = 1.5 x d = 1.5(4”) = 6.0” \[Ref: 1\]
max50
6. Determine dimensions of riprap apron
a. Determine minimum length of riprap apron
- L = 9 ft \[Ref: 1, Fig. 8.06a\]
a
b. Determine width of riprap apron
-Upstream width = 3d= 3(2.5 ft) = 7.5 ft \[Ref: 1, Fig. 8.06a\]
o
-Downstream width of apron
o W= d+ L = 2.5 ft + 9 ft = 11.5 ft
oa
c. Determine thickness of apron
-T = 1.5(d) = 1.5(6.0”) = 9.0” \[Ref: 1\]
max
- Use T = 15”
- Use appropriate filter fabric underneath apron.
Project No: 17-18-092 Sheet No: 4 of
Date:01/11/2019
Calcs Performed By:CMM
Calcs Checked By: NRP
Project Name:Custom Plastics Phase I Building Expansion
Subject: Rip Rap Apron
OBJECTIVE:
Design Riprap Apron to dissipate the 10-year flow discharging from FES-4
REFERENCES:
7. North Carolina Erosion and Sediment Control Manual, 2017.
8. “Hydraulics & Grate Capacity Calculations,” by Amicus Partners, PLLC,
01/11/2019.
TERMS:
3
Q
= 10-year peak flow, (ft/s)
10
d= diameter of discharge pipe, (in)
o
d= median stone size in a well-graded riprap apron, (in)
50
d= maximum stone diameter in riprap apron, (in)
max
L = length of riprap apron, (ft)
a
W = downstream width of riprap apron, (ft)
cfs = cubic feet per second
Tw = Tailwater
GIVEN/REQUIREMENTS:
Minimum design storm = 10-year\[Ref: 2\]
Q= 2.87 cfs\[Ref: 2\]
10
V= 8.16 ft/s \[Ref: 2\]
10
d= 18”\[Ref: 2\]
o
CALCULATIONS:
7. Determine median and maximum stone diameter
a. Determine median stone diameter
- d= 6”\[Ref: 1, Fig. 8.06a\]
50
b. Determine maximum stone size
-d = 1.5 x d = 1.5(6”) = 9.0” \[Ref: 1\]
max50
8. Determine dimensions of riprap apron
a. Determine minimum length of riprap apron
- L = 6 ft \[Ref: 1, Fig. 8.06a\]
a
b. Determine width of riprap apron
-Upstream width = 3d= 3(1.5 ft) = 4.5 ft \[Ref: 1, Fig. 8.06a\]
o
-Downstream width of apron
o W= d+ L = 1.5 ft + 6 ft = 7.5 ft
oa
c. Determine thickness of apron
-T = 1.5(d) = 1.5(9.0”) = 13.5” \[Ref: 1\]
max
- Use T = 15”
- Use appropriate filter fabric underneath apron.