Proposed HEC-22 Curb Inlet Design Equation...Proposed HEC-22 Curb Inlet Design Equation Presented by...
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TURNER - FAIRBANK HIGHWAY RESEARCH CENTER Hydraulic Engineering Virtual 2020 NHEC Proposed HEC - 22 Curb Inlet Design Equation Presented by Kornel Kerenyi, PhD Hydraulics Research Program Manager, Federal Highway Administration ** FHWA (2013), Hydraulic Engineering Circular No. 22, Third Edition: Urban Drainage Design Manual. HEC-22 (Eq.4-22a), Publication No.: FHWA-NHI-10-009. Accessed 8/31/2020. https://www.fhwa.dot.gov/engineering/hydraulics/pubs/10009/10009.pdf Source: FHWA.
Transcript of Proposed HEC-22 Curb Inlet Design Equation...Proposed HEC-22 Curb Inlet Design Equation Presented by...
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERHydraulic Engineering Virtual 2020 NHEC
Proposed HEC-22 Curb Inlet Design
Equation
Presented by
Kornel Kerenyi, PhD
Hydraulics Research Program Manager, Federal Highway Administration
** FHWA (2013), Hydraulic Engineering Circular No. 22, Third Edition: Urban Drainage Design Manual. HEC-22 (Eq.4-22a), Publication No.: FHWA-NHI-10-009. Accessed 8/31/2020. https://www.fhwa.dot.gov/engineering/hydraulics/pubs/10009/10009.pdf Source: FHWA.
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Symbol Definitions
Symbols Definition
C Constant in the side flow discharge equation
f(y*) Modification factor function of unit side flow
rate along the curb inlet opening
g Acceleration of gravity
H Total water head
K(θ) Coefficient that is a function of θ
Lt Curb inlet length required to intercept 100% of
gutter flow
M Overall coefficient of side flow that is a
function of K and θ
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERHydraulic Engineering Virtual 2020 NHEC
Symbol Definitions
Symbols Definition
Qs Side flow rate intercepted by the curb inlet
q Unit side flow rate along the curb inlet
opening
SL Roadway longitudinal slope
Sx Roadway cross slope
X Distance along the roadway
y* Dimensionless water depth along the curb
inlet opening
α Angle of the roadway cross slope
θ Angle of the roadway longitudinal slope
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERHydraulic Engineering Virtual 2020 NHEC
Problem Statement
Computed Discharge Izzard’s Equation
Observed Discharge Observed Discharge
Co
mp
ute
d D
isc
ha
rge
Izzard'sEquation
HEC22HEC-22
* Izzard, C. F. (1950) Tentative results on capacity of curb opening inlets. Proc., Highway Research Board, 11-13.
** FHWA (2013), Hydraulic Engineering Circular No. 22, Third Edition: Urban Drainage Design Manual. HEC-22 (Eq.4-22a), Publication No.: FHWA-NHI-10-009. Accessed 8/31/2020. https://www.fhwa.dot.gov/engineering/hydraulics/pubs/10009/10009.pdf
Source: FHWA.
Source: FHWA.
Source: FHWA.
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Proposed Method
Qs
θ
Sx
SL
Source: FHWA.
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Proposed Method (Cont’d.)
dQs
dx= −f∙q (1)
f = f 𝑦∗ determined by CFD∗∗ 2
**Computational Fluid Dynamics (CFD)
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y*
Sx
SL
θ
Proposed Method (Cont’d.)
Lt
Source: FHWA.
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Modification Factor Function
Proposed Method (Cont’d.)
Qs = f y* qdxLt
0
= M K θ CLt gH1.5
Modification Factor Function
f
y*Source: FHWA.
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERHydraulic Engineering Virtual 2020 NHEC
K
M
Water Profile Coefficients Sx=0.02
θ
Water Profile Coefficients Sx=0.02
Lt = 5 ft Lt = 10 ft Lt = 15 ft
K K
Proposed Method (Cont’d.)
Source: FHWA.Source: FHWA.
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERHydraulic Engineering Virtual 2020 NHEC
Proposed Method (Cont’d.)
• Curb inlet length of 5 ft
• Cross slope of 2 percent
• Without local depression
Longitudinal slope of 4 percent
Longitudinal slope of 0.5 percent
Longitudinal slope of 2 percent
Longitudinal slope of 0.1 percentSource: FHWA.
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Proposed Method (Cont’d.)
Qs = MCLt gH1.5
TURNER-FAIRBANK HIGHWAY RESEARCH CENTERHydraulic Engineering Virtual 2020 NHEC
Proposed Method (Cont’d.)
Co
mp
ute
d D
isc
ha
rge
Observed Discharge
Co
mp
ute
d D
isc
ha
rge
Observed Discharge
New Eq.
Izzard
HEC22
Muhammad
HEC-22
* Muhammad, A. F. (2018) “Interception Capacity of Curb Opening Inlets,” Dissertation, University of Texas at Austin.
Source: FHWA.Source: FHWA.
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QUESTIONS?
Kornel Kerenyi
