Rossman

Refactoring the SWMM 5 Help File – Links in SWMM5

Links in SWMM5

Links

Links are the conveyance components of a drainage system and always lie between a pair of nodes. Types of links include:

· Conduits
· Pumps
· Regulators
Conduits

Conduits are pipes or channels that move water from one node to another in the conveyance system. Their cross-sectional shapes can be selected from a variety of standard open and closed geometries. Irregular natural cross-section shapes are also supported, as are user-defined closed shapes.

The principal input parameters for conduits are:

· names of the inlet and outlet nodes
· offset height or elevation of the conduit above the inlet and outlet node inverts
· conduit length
· Manning’s roughness
· cross-sectional geometry
· entrance/exit losses (optional)
· seepage rate (optional)
· presence of a flap gate to prevent reverse flow (optional)
· inlet geometry code number if conduit acts as a culvert (optional).

Conduits designated as culverts are checked continuously during dynamic wave flow routing to see if they operate under Inlet Control as defined in the Federal Highway Administration’s publication Hydraulic Design of Highway Culverts (Publication No. FHWA-NHI-01-020, May 2005).

See Also

Conduit Properties

Cross-Section Editor

Culvert Code Numbers

Conduit Properties
Name User-assigned conduit name.
Inlet Node Name of node on the inlet end of the conduit (which is normally the end at higher elevation).
Outlet Node Name of node on the outlet end of the conduit (which is normally the end at lower elevation).
Description Click the ellipsis button (or press Enter) to edit an optional description of the conduit.
Tag Optional label used to categorize or classify the conduit.
Shape Click the ellipsis button (or press Enter) to edit the geometric properties of the conduit’s cross section.
Max. Depth Maximum depth of the conduit’s cross section (feet or meters).
Length Conduit length (feet or meters).
Roughness Manning’s roughness coefficient.

(Values for closed conduits)

(Values for open channels)

Inlet Offset Depth or elevation of the conduit invert above the node invert at the inlet end of the conduit (feet or meters).
Outlet Offset Depth or elevation of the conduit invert above the node invert at the outlet end of the conduit (feet or meters).
Initial Flow Initial flow in the conduit at the start of the simulation (flow units).
Maximum Flow Maximum flow allowed in the conduit (flow units) – use 0 or leave blank if not applicable.
Entry Loss Coeff. Head loss coefficient associated with energy losses at the entrance of the conduit. For culverts, refer to Culvert Inlet Loss Coefficientstable.
Exit Loss Coeff. Head loss coefficient associated with energy losses at the exit of the conduit. For culverts, use a value of 1.0.
Avg. Loss Coeff. Head loss coefficient associated with energy losses along the length of the conduit.
Flap Gate YES if a flap gate exists that prevents backflow through the conduit, or NO if no flap gate exists.
Culvert Code Code number of inlet geometry if conduit is a culvert subject to possible inlet flow control — leave blank otherwise. Refer to the table of Culvert Code Numbers.
Shaping a Link

Links can be drawn as polylines containing any number of straight-line segments that define the alignment or curvature of the link. Once a link has been drawn on the Study Area Map, interior points that define these line segments can be added, deleted, and moved.

To edit the interior points of a link:

1. Select the link to edit on the Map and put the map in Vertex Selection mode by either
· clicking the button,
· or selecting Edit >> Select Vertex from the Main Menu,
· or right-clicking on the link and selecting Vertices from the popup menu.
2. The mouse pointer will change shape to an arrow tip, and any existing vertex points on the link will be displayed as small open squares. The currently selected vertex will be displayed as a filled square.To select a particular vertex, click the mouse over it.
3. To add a new vertex to the link, right-click the mouse and select Add Vertex from the popup menu (or simply press the <Insert> key on the keyboard).
4. To delete the currently selected vertex, right click the mouse and select Delete Vertex from the popup menu (or simply press the <Delete> key on the keyboard).
5. To move a vertex to another location, drag it with the left mouse button held down to its new position.
6. While in Vertex Selection mode you can begin editing the vertices for another link by simply clicking on the link. To leave Vertex Selection mode, right click on the map and select Quit Editing from the popup menu, or simply select one of the other buttons on the Map Toolbar.

A link can also have its direction reversed (i.e., its end nodes switched) by right clicking on it and selecting Reverse from the pop-up menu that appears. Normally, links should be oriented so that the upstream end is at a higher elevation than the downstream end.

Weirs

Weirs, like orifices, are used to model outlet and diversion structures in a drainage system. Weirs are typically located in a manhole, along the side of a channel, or within a storage unit. They are internally represented in SWMM as a link connecting two nodes, where the weir itself is placed at the upstream node. A flap gate can be included to prevent backflow.

Five varieties of weirs are available, each incorporating a different formula for computing flow as a function of area, discharge coefficient and head difference across the weir:

· Transverse (rectangular shape)
· Side flow (rectangular shape)
· V-notch (triangular shape)
· Trapezoidal (trapezoidal shape)
· Roadway (broad crested rectangular weir used to model roadway crossings).

Weirs can be used as storage unit outlets under all types of flow routing. If not attached to a storage unit, they can only be used in drainage networks that are analyzed with Dynamic Wave flow routing.

The height of the weir crest above the inlet node invert can be controlled dynamically through user-defined Control Rules. This feature can be used to model inflatable dams.

Weirs can either be allowed to surcharge or not. A surcharged weir will use an equivalent orifice equation to compute the flow through it. Weirs placed in open channels would normally not be allowed to surcharge while those placed in closed diversion structures or those used to represent storm drain inlet openings would be allowed to.

The principal input parameters for a weir include:

· names of its inlet and outlet nodes
· shape and geometry
· crest height above the inlet node invert
· discharge coefficient.

See Also

Weir Properties

Control Rules

Weir Properties
Name User-assigned weir name.
Inlet Node Name of node on inlet side of weir.
Outlet Node Name of node on outlet side of weir.
Description Click the ellipsis button (or press Enter) to edit an optional description of the weir.
Tag Optional label used to categorize or classify the weir.
Type Weir type: TRANSVERSE, SIDEFLOW, V-NOTCH, TRAPEZOIDAL or ROADWAY.
Height Vertical height of weir opening (feet or meters)
Length Horizontal length of weir opening (feet or meters)
Side Slope Slope (width-to-height) of side walls for a V-NOTCH or TRAPEZOIDAL weir.
Inlet Offset Depth or elevation of bottom of weir opening from invert of inlet node (feet or meters).
Discharge Coeff. Discharge coefficient for flow through the central portion of the weir (for flow in CFS when using US units or CMS when using SI units). Typical values are: 3.33 US (1.84 SI) for sharp crested transverse weirs, 2.5 – 3.3 US (1.38 – 1.83 SI) for broad crested rectangular weirs, 2.4 – 2.8 US (1.35 – 1.55 SI) for V-notch (triangular) weirs. Discharge over Roadway weirs with a non-zero road width is computed using the FHWA HDS-5 method.
Flap Gate YES if the weir has a flap gate that prevents backflow, NO if it does not.
End Coeff. Discharge coefficient for flow through the triangular ends of a TRAPEZOIDAL weir. See the recommended values for V-notch weirs listed above.
End Contractions Number of end contractions for a TRANSVERSE or SIDEFLOW weir whose length is shorter than the channel it is placed in. Either 0, 1, or 2 depending if no ends, one end, or both ends are beveled in from the side walls.
Can Surcharge YES if the weir can surcharge (have an upstream water level higher than the height of the opening) or NO if it cannot.
Coeff. Curve Name of an optional WEIR type curve that allows the central Discharge Coefficient to vary as a function of head (in feet or meters). Does not apply to Roadway weirs.
ROADWAY WEIR
Road Width Width of roadway and shoulders (feet or meters)
Road Surface Type of road surface: PAVED or GRAVEL.
Pumps

Pumps are links used to lift water to higher elevations. A pump curve describes the relation between a pump’s flow rate and conditions at its inlet and outlet nodes. Five different types of pumps are supported:

Type1

An off-line pump with a wet well where flow increases incrementally with available wet well volume.

Type2

An in-line pump where flow increases incrementally with inlet node depth.

Type3

An in-line pump where flow varies continuously with head difference between the inlet and outlet nodes.

Type4

A variable speed in-line pump where flow varies continuously with inlet node depth.

Ideal

An "ideal" transfer pump whose flow rate equals the inflow rate at its inlet node. No curve is required. The pump must be the only outflow link from its inlet node. Used mainly for preliminary design.

The on/off status of pumps can be controlled dynamically by specifying startup and shutoff water depths at the inlet node or through user-defined Control Rules. Rules can also be used to simulate variable speed drives that modulate pump flow.

The principal input parameters for a pump include:

· names of the inlet and outlet nodes
· name of its pump curve (or * for an Ideal pump)
· initial on/off status
· startup and shutoff depths.

See Also

Pump Properties

Control Rules

Pump Properties
Name User-assigned pump name.
Inlet Node Name of node on the inlet side of the pump.
Outlet Node Name of node on the outlet side of the pump.
Description Click the ellipsis button (or press Enter) to edit an optional description of the the pump.
Tag Optional label used to categorize or classify the pump.
Pump Curve Name of the Pump Curve which contains the pump’s operating data (double-click to edit the curve). Enter * for an Ideal pump.
Initial Status Status of the pump (ON or OFF) at the start of the simulation.
Startup Depth Depth at inlet node when pump turns on (ft or m). Enter 0 if not applicable.
Shutoff Depth Depth at inlet node when pump shuts off (ft or m). Enter 0 if not applicable.
Orifices

Orifices are used to model outlet and diversion structures in drainage systems which are typically openings in the wall of a manhole, storage facility, or control gate. They are internally represented in SWMM as a link connecting two nodes. An orifice can have either a circular or rectangular shape, be located either at the bottom or along the side of the upstream node, and have a flap gate to prevent backflow.

Orifices can be used as storage unit outlets under all types of flow routing. If not attached to a storage unit node, they can only be used in drainage networks that are analyzed with Dynamic Wave flow routing.

The flow through an orifice is computed based on the area of its opening, its discharge coefficient, and the head difference across the orifice.

The height of an orifice’s opening can be controlled dynamically through user-defined Control Rules. This feature can be used to model gate openings and closings.

The principal input parameters for an orifice include:

· names of its inlet and outlet nodes
· configuration (bottom or side)
· shape (circular or rectangular)
· height above the inlet node invert
· discharge coefficient
· time to open or close.

See Also

Orifice Properties

Control Rules

Orifice Properties
Name User-assigned orifice name.
Inlet Node Name of node on the inlet side of the orifice.
Outlet Node Name of node on the outlet side of the orifice.
Description Click the ellipsis button (or press Enter) to edit an optional description of the orifice.
Tag Optional label used to categorize or classify the orifice.
Type Type of orifice (SIDE or BOTTOM).
Shape Orifice shape (CIRCULAR or RECT_CLOSED).
Height Height of orifice opening when fully open (feet or meters).Corresponds to the diameter of a circular orifice or the height of a rectangular orifice.
Width Width of rectangular orifice when fully opened (feet or meters)
Inlet Offset Depth or elevation of bottom of orifice above invert of inlet node (feet or meters).
Discharge Coeff. Discharge coefficient (unitless). A typical value is 0.65.
Flap Gate YES if a flap gate exists which prevents backflow through the orifice, or NO if no flap gate exists.
Time to Open/Close The time to open a closed (or close an open) gated orifice in decimal hours. Use 0 or leave blank if timed openings/closings do not apply. Use Control Rules to adjust gate position.
Outlets

Outlets are flow control devices that are typically used to control outflows from storage units. They are used to model special head-discharge relationships that cannot be characterized by pumps, orifices, or weirs. Outlets are internally represented in SWMM as a link connecting two nodes. An outlet can also have a flap gate that restricts flow to only one direction.

Outlets attached to storage units are active under all types of flow routing. If not attached to a storage unit, they can only be used in drainage networks analyzed with Dynamic Wave flow routing.

A user-defined rating curve determines an outlet’s discharge flow as a function of either the freeboard depth above the outlet’s opening or the head difference across it. Control Rules can be used to dynamically adjust this flow when certain conditions exist.

The principal input parameters for an outlet include:

· names of its inlet and outlet nodes
· height above the inlet node invert
· function or table containing its head (or depth) – discharge relationship.

See Also

Outlet Properties

Control Rules

Outlet Properties
Name User-assigned outlet name.
Inlet Node Name of node on inflow side of outlet.
Outlet Node Name of node on discharge side of outlet.
Description Click the ellipsis button (or press Enter) to edit an optional description of the outlet.
Tag Optional label used to categorize or classify the outlet.
Inlet Offset Depth or elevation of outlet above inlet node invert (ft or m).
Flap Gate YES if a flap gate exists which prevents backflow through the outlet, or NO if no flap gate exists.
Rating Curve Method of defining flow (Q) as a function of freeboard depth or head (y) across the outlet.

FUNCTIONAL/DEPTH – uses a power function Q = AyB where y is the freeboard depth above the outlet’s opening.

FUNCTIONAL/HEAD – uses a power function Q = AyB where y is the head difference across the outlet.

TABULAR/DEPTH – uses a tabulated curve of flow versus freeboard depth values.

TABULAR/HEAD – uses a tabulated curve of flow versus head difference values.

FUNCTIONAL
– Coefficient Coefficient (A) for the functional relationship between depth or head and flow rate.
– Exponent Exponent (B) used for the functional relationship between depth or head and flow rate.
TABULAR
– Curve Name Name of Rating Curve containing the relationship between depth or head and flow rate (double-click to edit the curve).
Cross-Section Editor

The Cross-Section Editor dialog is used to specify the shape and dimensions of a conduit’s cross-section.

When a shape is selected from the image list an appropriate set of edit fields appears for describing the dimensions of that shape. Length dimensions are in units of feet for US units and meters for SI units. Slope values represent ratios of horizontal to vertical distance. The Barrels field specifies how many identical parallel conduits exist between its end nodes.

The Force Main shape option is a circular conduit that uses either the Hazen-Williams or Darcy-Weisbach formulas to compute friction losses for pressurized flow during Dynamic Wave flow routing. In this case the appropriate C-factor (for Hazen-Williams) or roughness height (for Darcy-Weisbach) is supplied as a cross-section property. The choice of friction loss equation is made on the Dynamic Wave Simulation Options dialog. Note that a conduit does not have to be assigned a Force Main shape for it to pressurize. Any of the other closed cross-section shapes can potentially pressurize and thus function as force mains using the Manning equation to compute friction losses.

If a Custom shaped section is chosen, a drop-down edit box will appear where you can enter or select the name of a Shape Curve that will be used to define the geometry of the section. This curve specifies how the width of the cross-section varies with height, where both width and height are scaled relative to the section’s maximum depth. This allows the same shape curve to be used for conduits of differing sizes. Clicking the Edit button next to the shape curve box will bring up the Curve Editor where the shape curve’s coordinates can be edited.

If an Irregular shaped section is chosen, a drop-down edit box will appear where you can enter or select the name of a Transect object that describes the cross-section’s geometry. Clicking the Edit button next to the edit box will bring up the Transect Editor which allows you to edit the transect’s data.

Transects

Transects refer to the geometric data that describe how bottom elevation varies with horizontal distance over the cross section of a natural channel or irregular-shaped conduit. The figure below displays an example of a transect for a natural channel.

Each transect must be given a unique name. Conduits refer to that name to represent their shape. A special Transect Editor is available for editing the station-elevation data of a transect. SWMM internally converts these data into tables of area, top width, and hydraulic radius versus channel depth. In addition, as shown in the diagram above, each transect can have a left and right overbank section whose Manning’s roughness can be different from that of the main channel. This feature can provide more realistic estimates of channel conveyance under high flow conditions.

Transect Editor

The Transect Editor is invoked whenever a new Transect object is created or an existing Transect is selected for editing. It contains the following data entry fields:

Name

The name assigned to the transect.

Description

An optional comment or description of the transect.

Station/Elevation Data Grid

Values of distance from the left side of the channel along with the corresponding elevation of the channel bottom as one moves across the channel from left to right, looking in the downstream direction. The elevations can be relative to any reference point, such as the bottom of the channel, and not necessarily mean sea level. Up to 1500 data values can be entered.

Roughness

Values of Manning’s roughness for the left overbank, right overbank, and main channel portion of the transect. The overbank roughness values can be zero if no overbank exists.

Bank Stations

The distance values appearing in the Station/Elevation grid that mark the end of the left overbank and the start of the right overbank. Use 0 to denote the absence of an overbank.

Modifiers

The Stations modifier is a factor by which the distance between each station will be multiplied when the transect data is processed by SWMM. Use a value of 0 if no such factor is needed.

The Elevations modifier is a constant value that will be added to each elevation value.

The Meander modifier is the ratio of the length of a meandering main channel to the length of the overbank area that surrounds it. This modifier is applied to all conduits that use this particular transect for their cross section. It assumes that the length supplied for these conduits is that of the longer main channel. SWMM will use the shorter overbank length in its calculations while increasing the main channel roughness to account for its longer length. The modifier is ignored if it is left blank or set to 0.

Right-clicking over the Data Grid will make a popup Edit menu appear. It contains commands to cut, copy, insert, and paste selected cells in the grid as well as options to insert or delete a row.

Clicking the View button will bring up a window that illustrates the shape of the transect cross section.

Culvert Code Numbers

Circular Concrete

1 Square edge with headwall

2 Groove end with headwall

3 Groove end projecting

Circular Corrugated Metal Pipe

4 Headwall

5 Mitered to slope

6 Projecting

Circular Pipe, Beveled Ring Entrance

7 45 deg. bevels

8 33.7 deg. bevels

Rectangular Box; Flared Wingwalls

9 30-75 deg. wingwall flares

10 90 or 15 deg. wingwall flares

11 0 deg. wingwall flares (straight sides)

Rectangular Box;Flared Wingwalls and Top Edge Bevel:

12 45 deg flare; 0.43D top edge bevel

13 18-33.7 deg. flare; 0.083D top edge bevel

Rectangular Box, 90-deg Headwall, Chamfered / Beveled Inlet Edges

14 chamfered 3/4-in.

15 beveled 1/2-in/ft at 45 deg (1:1)

16 beveled 1-in/ft at 33.7 deg (1:1.5)

Rectangular Box, Skewed Headwall, Chamfered / Beveled Inlet Edges

17 3/4" chamfered edge, 45 deg skewed headwall

18 3/4" chamfered edge, 30 deg skewed headwall

19 3/4" chamfered edge, 15 deg skewed headwall

20 45 deg beveled edge, 10-45 deg skewed headwall

Rectangular Box, Non-offset Flared Wingwalls, 3/4" Chamfer at Top of Inlet

21 45 deg (1:1) wingwall flare

22 8.4 deg (3:1) wingwall flare

23 18.4 deg (3:1) wingwall flare, 30 deg inlet skew

Rectangular Box, Offset Flared Wingwalls, Beveled Edge at Inlet Top

24 45 deg (1:1) flare, 0.042D top edge bevel

25 33.7 deg (1.5:1) flare, 0.083D top edge bevel

26 18.4 deg (3:1) flare, 0.083D top edge bevel

Corrugated Metal Box

27 90 deg headwall

28 Thick wall projecting

29 Thin wall projecting

Horizontal Ellipse Concrete

30 Square edge with headwall

31 Grooved end with headwall

32 Grooved end projecting

Vertical Ellipse Concrete

33 Square edge with headwall

34 Grooved end with headwall

35 Grooved end projecting

Pipe Arch, 18" Corner Radius, Corrugated Metal

36 90 deg headwall

37 Mitered to slope

38 Projecting

Pipe Arch, 18" Corner Radius, Corrugated Metal

39 Projecting

40 No bevels

41 33.7 deg bevels

Pipe Arch, 31" Corner Radius,Corrugated Metal

42 Projecting

43 No bevels

44 33.7 deg. bevels

Arch, Corrugated Metal

45 90 deg headwall

46 Mitered to slope

47 Thin wall projecting

Circular Culvert

48 Smooth tapered inlet throat

49 Rough tapered inlet throat

Elliptical Inlet Face

50 Tapered inlet, beveled edges

51 Tapered inlet, square edges

52 Tapered inlet, thin edge projecting

Rectangular

53 Tapered inlet throat

Rectangular Concrete

54 Side tapered, less favorable edges

55 Side tapered, more favorable edges

56 Slope tapered, less favorable edges

57 Slope tapered, more favorable edges

Culvert Inlet Loss Coefficients
Type of Structure and Design of Entrance Coefficient
· Pipe, Concrete

Projecting from fill, socket end (groove-end)

Projecting from fill, sq. cut end

Headwall or headwall and wingwalls:

Socket end of pipe (groove-end)

Square-edge

Rounded (radius = D/12)

Mitered to conform to fill slope

*End-Section conforming to fill slope

Beveled edges, 33.7 deg or 45 deg bevels

Side- or slope-tapered inlet

0.2

0.5

0.2

0.5

0.2

0.7

0.5

0.2

0.2

· Pipe or Pipe-Arch, Corrugated Metal

Projecting from fill (no headwall)

Headwall or headwall and wingwalls square-edge

Mitered to conform to fill slope, paved or unpaved slope

*End-Section conforming to fill slope

Beveled edges, 33.7 or 45 bevels

Side- or slope-tapered inlet

0.9

0.5

0.7

0.5

0.2

0.2

· Box, Reinforced Concrete

Headwall parallel to embankment (no wingwalls):

Square-edged on 3 edges

Rounded on 3 edges to radius of D/12 or B/12

or beveled edges on 3 sides

Wingwalls at 30 deg to 75 deg to barrel:

Square-edged at crown

Crown edge rounded to radius of D/12

or beveled top edge

Wingwall at 10 deg to 25 deg to barrel:

Square-edged at crown

Wingwalls parallel (extension of sides):

Square-edged at crown

Side- or slope-tapered inlet

0.5

0.2

0.4

0.2

0.5

0.7

0.2

*Note: "End Sections conforming to fill slope," made of either metal or concrete, are the sections commonly available from manufacturers. From limited hydraulic tests they are equivalent in operation to a headwall in both inlet and outlet control. Some end sections, incorporating a closed taper in their design have a superior hydraulic performance. These latter sections can be designed using the information given for the beveled inlet.

Source: Federal Highway Administration (2005). Hydraulic Design of Highway Culverts, Publication No. FHWA-NHI-01-020.

Standard Arch Pipe Sizes

Concrete Arch Pipes

Code Rise (in) Span (in) Rise (mm) Span (mm)
1 11 18 279 457
2 13.5 22 343 559
3 15.5 26 394 660
4 18 28.5 457 724
5 22.5 36.25 572 921
6 26.625 43.75 676 1111
7 31.3125 51.125 795 1299
8 36 58.5 914 1486
9 40 65 1016 1651
10 45 73 1143 1854
11 54 88 1372 2235
12 62 102 1575 2591
13 72 115 1829 2921
14 77.5 122 1969 3099
15 87.125 138 2213 3505
16 96.875 154 2461 3912
17 106.5 168.75 2705 4286

Corrugated Steel, 2-2/3 x 1/2" Corrugation

Code Rise (in) Span (in) Rise (mm) Span (mm)
18 13 17 330 432
19 15 21 381 533
20 18 24 457 610
21 20 28 508 711
22 24 35 610 889
23 29 42 737 1067
24 33 49 838 1245
25 38 57 965 1448
26 43 64 1092 1626
27 47 71 1194 1803
28 52 77 1321 1956
29 57 83 1448 2108

Corrugated Steel, 3 x 1" Corrugation

Code Rise (in) Span (in) Rise (mm) Span (mm)
30 31 40 787 1016
31 36 46 914 1168
32 41 53 1041 1346
33 46 60 1168 1524
34 51 66 1295 1676
35 55 73 1397 1854
36 59 81 1499 2057
37 63 87 1600 2210
38 67 95 1702 2413
39 71 103 1803 2616
40 75 112 1905 2845
41 79 117 2007 2972
42 83 128 2108 3251
43 87 137 2210 3480
44 91 142 2311 3607

Structural Plate, 18" Corner Radius

Code Rise (in) Span (in) Rise (mm) Span (mm)
45 55 73 1397 1854
46 57 76 1448 1930
47 59 81 1499 2057
48 61 84 1549 2134
49 63 87 1600 2210
50 65 92 1651 2337
51 67 95 1702 2413
52 69 98 1753 2489
53 71 103 1803 2616
54 73 106 1854 2692
55 75 112 1905 2845
56 77 114 1956 2896
57 79 117 2007 2972
58 81 123 2057 3124
59 83 128 2108 3251
60 85 131 2159 3327
61 87 137 2210 3480
62 89 139 2261 3531
63 91 142 2311 3607
64 93 148 2362 3759
65 95 150 2413 3810
66 97 152 2464 3861
67 100 154 2540 3912
68 101 161 2565 4089
69 103 167 2616 4242
70 105 169 2667 4293
71 107 171 2718 4343
72 109 178 2769 4521
73 111 184 2819 4674
74 113 186 2870 4724
75 115 188 2921 4775
76 118 190 2997 4826
77 119 197 3023 5004
78 121 199 3073 5055

Structural Plate, 31" Corner Radius

Code Rise (in) Span (in) Rise (mm) Span (mm)
79 112 159 2845 4039
80 114 162 2896 4115
81 116 168 2946 4267
82 118 170 2997 4318
83 120 173 3048 4394
84 122 179 3099 4547
85 124 184 3150 4674
86 126 187 3200 4750
87 128 190 3251 4826
88 130 195 3302 4953
89 132 198 3353 5029
90 134 204 3404 5182
91 136 206 3454 5232
92 138 209 3505 5309
93 140 215 3556 5461
94 142 217 3607 5512
95 144 223 3658 5664
96 146 225 3708 5715
97 148 231 3759 5867
98 150 234 3810 5944
99 152 236 3861 5994
100 154 239 3912 6071
101 156 245 3962 6223
102 158 247 4013 6274

Source: Modern Sewer Design (Fourth Edition), American Iron and Steel Institute, Washington, DC, 1999.

Standard Elliptical Pipe Sizes
Code Minor

Axis (in)

Major

Axis (in)

Minor

Axis (mm)

Major

Axis (mm)

1 14 23 356 584
2 19 30 483 762
3 22 34 559 864
4 24 38 610 965
5 27 42 686 1067
6 29 45 737 1143
7 32 49 813 1245
8 34 53 864 1346
9 38 60 965 1524
10 43 68 1092 1727
11 48 76 1219 1930
12 53 83 1346 2108
13 58 91 1473 2311
14 63 98 1600 2489
15 68 106 1727 2692
16 72 113 1829 2870
17 77 121 1956 3073
18 82 128 2083 3251
19 87 136 2210 3454
20 92 143 2337 3632
21 97 151 2464 3835
22 106 166 2692 4216
23 116 180 2946 4572

Note: The Minor Axis is the maximum width for a vertical ellipse and the full depth for a horizontal ellipse while the Major Axis is the maximum width for a horizontal ellipse and the full depth for a vertical ellipse.

Source: Concrete Pipe Design Manual, American Concrete Pipe Association, 2011 (www.concrete-pipe.org).

Privileged and Confidential Communication: This electronic mail communication and any documents included hereto may contain confidential and privileged material for the sole use of the intended recipient(s) named above. If you are not the intended recipient (or authorized to receive for the recipient) of this message, any review, use, distribution or disclosure by you or others is strictly prohibited. Please contact the sender by reply email and delete and/or destroy the accompanying message.

Leave a Reply