Part Properties Tab (Structure Properties Dialog Box)

Use this tab to view or change properties associated with this structure.

This tab displays the properties associated with this structure, along with their current values. Structure properties define a variety of characteristics of the structure object, including its basic size and shape and elevation adjustment behavior.

Some properties are specific to a certain type of structure. For example, only junction structures use rim and sump behavior properties. Only inlet-outlet structures use properties that define headwalls such as Headwall Base Width.

Some properties are read-only and others are editable. To change an editable property, double-click on the Value field and enter a new value, or select one from the list.

This tab displays the properties associated with this structure, along with their current values. Structure properties define a variety of characteristics of the structure object, including its basic size and shape and elevation adjustment behavior.

Some properties are specific to a certain type of structure. For example, only junction structures use rim and sump behavior properties. Only inlet-outlet structures use properties that define headwalls such as Headwall Base Width.

Some properties are read-only and others are editable. To change an editable property, double-click on the Value field and enter a new value, or select one from the list.

General

These properties specify general characteristics of the structure, such as the structure elevation at its insertion point, and the surface and alignment referenced.

• Surface Elevation At Insertion Point: Specifies the elevation at the structure’s insertion point.
• Reference Surface: Specifies the surface referenced by the structure.
• Reference Alignment: Specifies the alignment referenced by the structure.

Geometry

These properties specify characteristics such as the structure’s rotation angle, offset, station data, and the number of pipes that are currently connected to the structure.

• Structure Rotation Angle: Specifies the structure’s rotation angle.
• Structure Offset: Specifies the structure’s offset.
• Structure Northing: Specifies the structure’s northing.
• Structure Easting: Specifies the structure’s easting.
• Connected Pipes: Specifies the number of pipes currently connected to the structure.

Hydraulic Properties

These properties specify the hydraulic grade line, the energy grade line, and the junction loss values for pipe networks that contain this data.

Hydraulic grade lines and energy grade lines, when present, are displayed as a straight line through structures, connected between the HGL Up or EGL Up property from one pipe to the HGL Down or EGL Down property of the next pipe. For more information, see To Work With Hydraulic Property Data for Pipe Networks.

• Hydraulic Grade Line: Specifies the elevation of the hydraulic grade line for pipe networks that contain this data.
• Energy Grade Line: Specifies the elevation of the energy grade line for pipe networks that contain this data.
• Known Capacity: Specifies the known capacity for pipe networks that contain this data.
• Known Flow: Specifies the known flow to a structure. This value is used by the Analyze Gravity Network command in addition to any flow resulting from a catchment.
• Bypass Target: Represents where water flowing past an On Grade inlet would flow to. Select another structure or <none>. When you select <none>, Offsite is displayed in the Bypass Target field.

  This property is displayed in the dialog box when the Structure Type in the Part Data section is set to Grate Inlet, Curb Inlet, or Combination and when the Inlet Location property is set to On Grade.

• Inlet Location: Specifies the inlet type.
  • On Grade: Use for storm drain inlets which are located on slopes. An on‐grade storm drain inlet is able to capture some, but not always all stormwater runoff. It captures all stormwater runoff at smaller flowrates, but as flowrates increase a point is reached where some stormwater bypasses the inlet, perhaps continuing to another storm drain inlet further downstream with additional flows joining it along the way.
  • On Sag: Use for storm drain inlets which are located at low points (or depressions).
  • None: Use for structures which are not inlets.

  This property is displayed in the dialog box when the Structure Type is set to Grate Inlet, Curb Inlet, or Combination.

  Note: This property supports a process for translating Autodesk Civil 3D part data and converting it Storm and Sanitary Analysis elements. When exporting to Storm and Sanitary Analysis, Inlet Sag (a True/False value) will be set in the STM file according to the Autodesk Civil 3D structure's Inlet Location value. Upon import into Storm and Sanitary Analysis, the Inlet Sag value from the STM file is used to select the appropriate Storm and Sanitary Analysis part for each part in the STM file.

Insertion Rim Behavior

These properties are associated with junction structures only. They specify the structure’s rim elevation and adjustment behavior.

• Insertion Rim Elevation: Specifies the current elevation of the structure rim. This cannot be edited if Automatic Surface Adjustment property is set to True.
• Automatic Surface Adjustment: Specifies whether or not to automatically adjust the rim elevation to the referenced surface, including the Surface Adjustment Value. When this property is set to True, grip editing the structure modifies the surface adjustment factor. When this property is set to False, grip editing the structure modifies the rim elevation.
• Surface Adjustment Value: If Automatic Surface Adjustment is set to True, the rim elevation is automatically adjusted by the surface elevation, plus the value specified here. If the structure is moved, resulting in the structure elevation changing, the structure automatically adjusts its elevation.

Sump Behavior

These properties are associated with junction structures only. They specify the structure’s behavior, elevation, and the depth of the structure’s sump.

• Sump Elevation: Specifies the elevation of the structure’s sump, measured at the inside bottom of the structure. When this property is enabled, grip editing the structure modifies the sump elevation.
• Sump Depth: Specifies the depth of the sump area, measured from the inside bottom of the structure to the lowest pipe invert of all pipes connected to the structure. When this property is enabled, grip editing the structure modifies the sump depth.
• Control Sump By: Specifies if the sump depth is controlled by the depth based on the lowest pipe invert, or by a specific elevation value of the sump.

Tailwater Condition

Specifies the method in which the depth of tailwater at the outfall part is determined. This provides an initial elevation value for the hydraulic analysis of the pipe network when using either the Analyze Gravity Network command, or the Analyze Drainage System command.

• Elevation: Specifies a user-defined elevation for the tailwater depth. Enter the elevation in the field below the drop-down list.
• (dc + D)/2: Specifies that the tailwater depth is the average of the critical depth and diameter of the pipe that is upstream from the outfall part. The Urban Drainage Design Manual Third Edition, Hydraulic Engineering Circular No. 22 (HEC-22) recommends using this value, unless the tailwater elevation is known and higher than (dc + D)/2.
  Note: This tailwater condition is not supported by the Analyze Drainage System command, so the Free tailwater condition will be used instead when analyzing the drainage system.
• Crown: Specifies that the tailwater depth is assumed to be equal to the crown of the pipe that is upstream from the outfall part.
• Normal Depth: Specifies that the tailwater is assumed to be at normal depth (as determined by Manning's equation).
• Critical Depth: Specifies that the tailwater is assumed to be at critical depth.
  Note: This tailwater condition is not supported by the Analyze Drainage System command, so the Free tailwater condition will be used instead when analyzing the drainage system.
• Elevation Curve: Specifies that the tailwater is based on an elevation curve that varies with time. The elevation curve will need to be selected when analyzing the drainage system.
  Note: This tailwater condition is not supported by the Analyze Gravity Network command, and a tailwater elevation of zero will be used when analyzing the gravity pipe network.
• Free: Specifies that the tailwater is based on free discharge. During analysis the lesser of the calculated critical depth and normal depth will be used as the tailwater elevation.
  Note: This tailwater condition is not supported by the Analyze Gravity Network command, and a tailwater elevation of zero will be used when analyzing the gravity pipe network.

Gutter Details

These properties are displayed in the dialog box when the Structure Type is set to Grate Inlet, Curb Inlet, or Combination. These are not physical properties of the inlet structure but rather are properties of the roadway area around the inlet. They are used by the Analyze Gravity Network command for inlet analysis calculations.

• Road Sx: Specifies the road cross slope.
• Gutter Sw: Specifies the gutter cross slope.
• Gutter Width: Specifies the gutter width.
• Longitudinal Slope: Specifies the slope along the road at the inlet. This property is available when the Inlet Location property in the Hydraulic Properties section is set to On Grade.
• Gutter n Value: Specifies the roughness of the gutter material (usually a type of concrete).

Note: When the Structure Type is set to Grate Inlet, Curb Inlet, or Combination, you can also specify the Bypass Target and Inlet Location in the Hydraulic Properties section.

Part Data

These properties specify a variety of part characteristics, such as part type, part subtype, and the part size name as defined in the part catalog. Some of these properties define the part’s basic shape and behavior, and therefore are read-only.

• Part Type: Specifies structure’s part type.
• Part Subtype: Specifies structure’s subtype.
• Part Description: Specifies structure’s description.
• Part Size Name: Specifies the part size name.
• Structure Type: Specifies the type of structure: Grate Inlet, Curb Inlet, Combination, Outfall, or Manhole. This property is used by the Analyze Gravity Network command to determine the type of inlet calculations to perform. This property also controls which other properties are displayed in the dialog box.
• Grate Width: Specifies the grate width. This dimension is perpendicular to flow along the gutter. This value is used by the Analyze Gravity Network command for inlet analysis calculations.

  This property is displayed in the dialog box when the Structure Type is set to Grate Inlet or Combination.

• Grate Length: Specifies the grate length. This dimension is in the direction of flow along the gutter. This value is used by the Analyze Gravity Network command for inlet analysis calculations.

  This property is displayed in the dialog box when the Structure Type is set to Grate Inlet or Combination.

• Grate Open Area: Specifies the grate open area. This value is used by the Analyze Gravity Network command for inlet analysis calculations.

  This property is displayed in the dialog box when the Structure Type is set to Grate Inlet or Combination.

• Curb Opening Height: Specifies the curb opening height. This value is used by the Analyze Gravity Network command for inlet analysis calculations.

  This property is displayed in the dialog box when the Structure Type is set to Curb Inlet or Combination.

• Curb Opening Length: Specifies the curb opening length. This value is used by the Analyze Gravity Network command for inlet analysis calculations.

  This property is displayed in the dialog box when the Structure Type is set to Curb Inlet or Combination.

• Local Depression: Specifies the elevation difference between the inlet opening and the gutter when the inlet is depressed. This value is used by the Analyze Gravity Network command for inlet analysis calculations.

  This property is displayed in the dialog box when the Structure Type is set to Curb Inlet, Grate Inlet, or Combination.

• Benching Method: Specifies the benching method: Depressed or Sump, Flat (Level), Half Benched, Full Benched, or Improved. Benching refers to the formation of a channel in the bottom of the structure to provide a smooth transition from the inlet to the outlet. Please refer to the Urban Drainage Design Manual, Hydraulic Engineering Circular No. 22 (HEC-22), Third Edition, published by the U.S. Department of Transportation Federal Highway Administration, sections 6.2.5 and 7.1.6.7.
• Structure Shape: Specifies the basic primitive shape of the structure, as defined from the part catalog. For example, headwalls are typically defined in the part catalog as Bounding box shape, and manholes are typically defined as cylindrical shaped.
• Vertical Pipe Clearance: Specifies the clearance required from the top outside of the highest pipe connected to the structure, to the rim. This is defined in the catalog and ensure that pipes enter the structure at an appropriate elevation. For example, it prevents a pipe from entering through the cone of structure.
• Rim To Sump Height: Specifies the distance between the sump to the structure’s rim. This property is for junction structures only.
• Headwall Base Width: Specifies the width of the base of the headwall. This property is for inlet-outlet structures only.
• Headwall Base Thickness: Specifies the thickness of the base of the headwall. This property is for inlet-outlet structures only.
• Wall Thickness: Specifies the wall thickness for this structure, measured from the inside edge of the structure to the outside edge of the structure. This property is for junction structures only.
• Floor Thickness: Specifies the thickness of the bottom of the structure. This property is for junction structures only.
• Material: Specifies the material defined for this part. This optional property is used mainly for labeling purposes. It allows you to identify the type of material used to construct this part.
• Frame: This optional property specifies the model or type of frame used for a structure.
• Grate: This optional property specifies the model or type of grate used for a structure intended to be used as a catchbasin.
• Cover: This optional property specifies the model or type of cover used for a structure intended to be used as a manhole.
• Frame Height: Specifies the height of the structure’s frame. This property is for junction structures only.
• Frame Diameter: Specifies the diameter of the structure’s frame. This property is for junction structures only.
• Frame Length: Specifies the length of the structure’s frame. This property is for junction structures only.
• Frame Width: Specifies the width of the structure’s frame. This property is for junction structures only.
• Barrel Height: Specifies the height of the barrel section of the structure. This property is for two-tiered junction structures only.
• Barrel Pipe Clearance: This property lets you determine how close to the structure’s rim you can position a pipe. It is used for two-tiered junction structures only and specifies the clearance required above the top of the barrel section of the structure. It is similar to Vertical Pipe Clearance, but only describes the transition zone between the access cylinder and the larger barrel cylinder of a two-tiered structure.
• Cone Height: Specifies the height of the cone shaped section of the structure. This property is for two-tiered junction structures only.
• Slab Thickness: Specifies the thickness of the structure slab. This property is for junction structures only.
• Inner Structure Diameter: Specifies the inner diameter for this structure. This property is for junction structures only.
• Structure Height: Specifies the total height for this structure, measured from the bottom outside edge of the structure to the top outside edge of the structure.
• Structure Diameter: Specifies the diameter for this structure, measured from the outside edges of the structure. Circular shaped structures typically use the diameter property while non-circular structures use width and length.
• Structure Width: Specifies the width for this structure, measured from the outside edges of the structure. Non-circular shaped structures typically use the width and length properties while circular structures use diameter.
• Structure Length: Specifies the length for this structure, measured from the outside edges of the structure. Non-circular shaped structures typically use the width and length properties while circular structures use diameter.