SLIDE 1
Small Structure
Alex Schwinghamer, EI Hydraulics Engineer, INDOT
Aschwinghamer@indot.in.gov February 7, 2017
Agenda
Definition Surveys Serviceability Sump Requirements Replacement Options and Sizing Questions
Small Structure Alex Schwinghamer, EI Hydraulics Engineer, INDOT - - PowerPoint PPT Presentation
Small Structure Alex Schwinghamer, EI Hydraulics Engineer, INDOT - - PowerPoint PPT Presentation
Small Structure Alex Schwinghamer, EI Hydraulics Engineer, INDOT Aschwinghamer@indot.in.gov February 7, 2017 Agenda Definition Surveys Serviceability Sump Requirements Replacement Options and Sizing Questions Definition
SLIDE 2
SLIDE 3
Definition
Federal Highway Administration
(FHWA) – span of 20 ft or less
(IDM Fig 203-2A)
Minimum Pipe Sizes
(IDM Fig. 203-2B)
SLIDE 4
Surveys
Any PE or LS can provide a
relative survey
Relative Surveys should have a
definite “benchmark”
Outlet or pavement grade, etc.
Survey sheet provided on
Hydraulics Website as Field Data Form
SLIDE 5
SLIDE 6
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 7
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 8
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 9
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 10
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 11
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 12
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 13
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 14
Surveys
Station ruler should be relatively taught for cross section
Outside of Scour Hole
Measure Pipe Sizes
I nlet and outlet
Pavement grade
Upstream structures and restrictions
Downstream Restrictions
Weirs and Dams
Signs of Overtopping
SLIDE 15
Q= 125 cfs 2:1 slopes 0.0012 channel slope nchannel= 0.035
Woods and crops on outer banks
5’ cmp w/ 6” sump thin edge 8’ channel bottom
Trapezoidal vs I rregular
SLIDE 16
Trapezoidal vs I rregular
TW depths:
- Irreg. = 3.10 ft
- Trap. = 3.41 ft
HW elevations
- Irreg. = 105.57 ft
- Trap. = 105.64 ft
BW depths
- Irreg. = 2.47 ft
- Trap. = 2.23 ft
SLIDE 17
Serviceability
SLIDE 18
Serviceability
BW = HW – (USinvert + TWexist) BWprop = BWexist + (HWprop – HWexist)
SLIDE 19
Serviceability
SLIDE 20
Serviceability
SLIDE 21
Serviceability
SLIDE 22
Sump Requirements
SLIDE 23
- 1. Prefer Circular
- Smooth, Semi-smooth, Corrugated
Pipe Sizing
SLIDE 24
- 1. Prefer Circular
- Smooth, Semi-smooth, Corrugated
- 2. CMPA, R.C. Elliptical, and Box options
- Corrugated Aluminum Boxes = Special
Provision
Pipe Sizing
SLIDE 25
- 1. Prefer Circular
- Smooth, Semi-smooth, Corrugated
- 2. CMPA, R.C. Elliptical, and Box options
- Corrugated Aluminum Boxes = Special
Provision
- 3. Mega Box, 3-Sided Structures, and
Arches
- Prefer Single Span Structures
- Open Bottom Metal Arches typically not used
Pipe Sizing
SLIDE 26
Pipe Sizing
Check n-values Use inner dimensions I nclude haunches I nlet Configurations
Concrete structures get headwall All others are thin edge projecting
There are smooth pipes that are metal.
Match span and open area of existing I nclude more than one option No Drop at outlet unless designed as such Channel invert = outlet invert + sump Use irregular cross sections not trapezoidal Existing CMPA’s should not be modeled as
Elliptical
SLIDE 27