Create/Edit Kerb Return

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Introduction

This command can be used to create Kerb Return Strings using parametric inputs or by selection of a user defined alignment.  If the kerb return has already been created, this command gives the designer an opportunity to change the horizontal geometry of the kerb return as well as the interaction with the incoming and outgoing Road Strings.

If a new kerb is to be created the software undertakes the following tasks once the intersection quadrant is selected:

• Locates the road edge of the Main and Side Road at a selected intersection using the user selected location
• Creates/Edits an alignment, matching the road edge of the Main and Side Roads and maintaining tangency relative to the Road centerline alignments, using Styles set by the designer
• Automatically generates an Existing surface and Design profile within Advanced Road Design.  The Design profile matches the incoming and outgoing levels and grades and includes parabolic vertical curve/s through the kerb return to form a smooth profile.

This command assumes that the Roads have been created (not necessarily the final designed profile or cross section of the roads).

Once the kerb returns have been created users can:

• Edit the profile of the kerb returns by changing the profile of the Main and/or Side roads using the Create/Edit Roads command.
• Edit the kerb return design profile using the Create/Edit Roads command.
• Change the automatic redesign options for the kerb return/s by editing the Kerb Design Controls

Road String Trimming when the Auto Model command is run 

When a Kerb Return String is created, the Main and Side road cross sections are 'trimmed' for the kerb return.  This occurs ONLY when the Auto Model command is run. 

The Side Road is trimmed back to the centreline (red dashed lines).

The Main Road is trimmed back to the 'Intersection Through Code' (purple dashed lines).  The Intersection Through Code is defined in the Active Drawing Settings form.

The kerb return adds an extra code (called LDUM or RDUM) to extend a 'pavement' section into the void between the kerb alignment and the trimmed road sections.  This code automatically adopts the full position of the side road centreline or the main road edge code, whichever is closest.

Note: The Template can be set up to insert pavement subgrade in this section.   The user should set subgrade behaviour if the code pair is C.L. and LDUM/RDUM, or LEB/REB and LDUM/RDUM).

Form Interface

The form is separated into three parts:

• Left side.  This is the inputs area
• Right top section.  This is a dynamic graphics window which will update as the user hovers over each input.  It provides a visual description of what the input means
• Right Bottom section.  This text panel provides information about the input the user is hovered over.

Kerb Return Settings

When a Kerb Return String is created using this command many attributes are adopted and applied from the Active Drawing Settings - Kerb Details tab, including:

• The Cross Section Template applied
• The subgrade layers applied (established by applying a Template)
• The batter (daylight) slope conditions to apply between the first and last cross section for the Kerb Return String
• The sampling frequency along the kerb return
• The cross section sample width
• Parameters governing the search algorithm to locate the kerb start and end locations

Many of the above settings can be adjusted at the time of creating the kerb return, however the initial values are adopted from the Active Drawing Settings - Kerb Details.  The kerb return form will, at the time of creation, support user selection of the template and batters.

Special Notes on Kerb Templates - Template Details

Details

After starting this command the user will need to confirm the location of the kerb return required.  From the command prompt, graphically select the intersection where the kerb return is required.

The following form will be displayed:

Note: After the Kerb Return is created the designer can use the Create/Edit Roads command to get access to the vertical grading and cross sections of the kerb return.
Kerb Name	This is generated by the software however can be overridden by the user.
Main Road	The name of the Main Road selected.  Informational only.
Side Road	The name of the Side Road selected.  Informational only.
Template	Assign a cross section template for the kerb return upon creation
Picklist	Select the Template to apply.  Using 'Auto' will set the kerb cross sections to be created by connecting matching (excluding L and R prefix) codes on the Main and Side roads to form cross section codes.
Omit Batters/Daylight	Tick on to exclude batters/daylight from the kerb return.  This toggle applies only if the Template is set to 'Auto'.
Batter Slope	Set the batter slopes for the kerb return
Cut 1:	Type in the value for the distance to travel horizontally for every 1 metre travelled vertically (Rise:Run)
Fill 1:	Type in the value for the distance to travel horizontally for every 1 metre travelled vertically (Rise:Run)
Connection	Sets the code that the kerb returns connect to on the main and side road.  This code must exist on the main and side road, at least two sampled sections beyond the kerb connection point.
Match to Code	The kerb return is able to be connected to any code of the Road cross sections.  The selected code must exist on both roads at the intersection. Use the pick list to select the cross section code to match to.
Horizontal Geometry	Establish the method and parameters for creating the horizontal geometry of the kerb return alignment.  The alignment be will set to connect to the 'Match to Code'.
Single Arc	The Single Arc tab is used to create a kerb return with a single radius. Radius Type in a value for the radius of the return Extension Optionally extend the kerb return alignment and string along the Match to Code of the Main Road and Side Road. Note: This will cause modelling overlaps of the Match to Code for the Main Road.  Model Builder is recommended to correct this overlap. Click on the Create/Update Alignment button at the bottom of the form to output the kerb alignment and string: Change the radius and click on the Create/Update Alignment button again to redesign the alignment.
Compound Type 1	The 3 Centered (1) tab is used to create a kerb return made up of three radii, selecting the start and end locations. Chainage on Main Type in the Chainage on the Main Road to Start/End the kerb alignment.  Click on the icon to select the location from the screen Chainage on Side Type in the Chainage on the Side Road to End/Start the kerb alignment.  Click on the icon to select the location from the screen Radius 1 First radius of the return Radius 2 Second radius (center arc) of the return Radius 3 Third radius of the return Extension Optionally extend the kerb return alignment and string along the Match to Code of the Main Road and Side Road. Note: This will cause modelling overlaps of the Match to Code for the Main Road.  Model Builder is recommended to correct this overlap. Click on the Create/Update Alignment button at the bottom of the form to output the kerb alignment and string: Note: An error message will be displayed if there is no geometric solution for the specified parameters. Change the radius or other parameters and click on the Create/Update Alignment button again to redesign the alignment.
Compound Type 2	TUsed to create a kerb return made up of three radii, a circle for the center point of the mid radius. Centre X Centre Y Type in the x and y values to set the location of the center point for the middle radius defining the return.  Click on the icon to select the location from the screen.  Users must select an arc or circle from the drawing. Radius 1 First radius of the return Radius 2 Second radius (center arc) of the return Radius 3 Third radius of the return Extension Optionally extend the kerb return alignment and string along the Match to Code of the Main Road and Side Road. Note: This will cause modelling overlaps of the Match to Code for the Main Road.  Model Builder is recommended to correct this overlap. Click on the Create/Update Alignment button at the bottom of the form to output the kerb alignment and string: Note: An error message will be displayed if there is no geometric solution for the specified parameters. Change the radius or other parameters and click on the Create/Update Alignment button again to redesign the alignment.
Specify	The Specify tab is used to create a kerb return from a user defined alignment. Alignment Use the pick list to select the required alignment for the kerb return Extension Optionally extend the kerb return alignment and string along the Match to Code of the Main Road and Side Road. Note: This will cause modelling overlaps of the Match to Code for the Main Road.  Model Builder is recommended to correct this overlap. Click to select the alignment directly from the drawing. Notes: All Alignments will be listed in the pick list.  Kerb Alignments already created will appear at the top of list and will be separated from all other alignments available by a couple of blank lines. For Civil 3D Users, alignments defined with a 'k-' prefix (not case sensitive) in the description field of the alignment will also appear in the top portion of the pick list. For Non-Civil 3D Users, alignments of type Kerb Return will also appear in the top portion of the pick list. Designers must design the alignment in the correct direction (either clockwise or counter-clockwise, depending on the side of the road driven on). Click on the Create/Update Alignment button at the bottom of the form to output the kerb alignment and string: The specified alignment will be MOVED to ensure it connects to the edge of the Main and Side Roads. An error message will be displayed if there is no geometric solution for the specified alignment.
Create/Update Alignment	Click on this button to create/update the kerb return string at the intersection.  Change the design parameters and click this button to update the horizontal geometry of the kerb alignment.
Delete Kerb	Click on this button to delete the Kerb Return string.  This is the recommended method for remove a kerb return string. Yes Click to delete the Kerb Return No Click to cancel the deletion of the Kerb Return
	Pan and zoom to your desired location in the drawing canvas and click Esc to finish.
Hover Image	This window will update based on the hover location of the mouse on the form.
Design Flag	This enables the user to set how the kerb profile will be designed, after it has been created.  The following options can be selected: Automatic Re-Design The software continuously recalculates the profile to match the incoming and outgoing grades at the start and end of the kerb return and creates vertical curve/s to smoothly transition through the return. The automatic redesign control can be overridden in the Vertical Grading Editor - if the designer edits the vertical grading it will automatically reset the kerb return to 'Keep Internal Design' Keep Internal Design This enables the designer to manually edit the profile between the IP's created at the start of the kerb return (matching the incoming Road level) and at the end of the kerb return (matching the outgoing Road level) Keep Internal Design and Match Grades This enables the designer to adjust the internal levels.  The software will attempt to maintain the incoming and outgoing grades that have been manually set by the designer.  The IP's at the start and end of the kerb return automatically and continuously match the edge of the Main Road and Side Road. Apply and Exit Apply and exit the form. Cancel Exit the form without changing any settings.
Show VGE on Close	If ticked on, when the form is closed the Vertical Grading Editor for the kerb return will open, allowing for redesign vertically and adjustments to cross sections.
Close	Click to close the form.

Alignment Creation Notes

Upon clicking the Create/Update Alignment button the kerb return alignment is created with the specified geometry (assuming a viable solution is available) and is automatically matched to the edge of the roads for the Main and Side Roads using the 'Match to Code' code.

Redesigning and viewing the Template in an interactive design environment can be achieved at any time by using the Create/Edit Roads command and selecting the kerb alignment - this will open the Vertical Grading Editor and include the kerb profile for redesign and review.

Note: Intersections for Crossing Roads.  The software will scan the Main and Side Roads for crossing alignments.  If it detects crossing alignments and a Side Road has not been defined, the user will be prompted to nominate the side road at all crossing roads.  The assignation of the Side and Main roads at intersections needs to be defined once only.

Users wanting to change the assignation of the Side Road at crossing intersections should refer to the Nominate Side Roads for Crossing Roads command.

Note: By default, Kerb Return Strings automatically redesign themselves to achieve the following:

• match the incoming and outgoing grade and elevation at the start and end of the kerb return (where they meet the Main and/or Side Roads)
• apply smooth transition parabolic curve/s to facilitate the different grades/levels between the Main and Side Road edge of road profiles.  The rules for the automated vertical curve/s is as follows:
  • Projection of the incoming and outgoing grades into the curb return finds an intersection
    • One IP will be created in the kerb return tangent to the incoming and outgoing grades of the kerb return, and
    • One vertical curve will be applied through the return, with a length of 1/2 the total length of the kerb return
  • Projection of the incoming and outgoing grades do not find an intersection
    • Two IP's will be created in the kerb return located at 1/4 and 3/4 points through the kerb return and using the incoming or outgoing grades, and
    • Two vertical curves of equal length are created at the two IP's each with a length of 1/2 the total length of the kerb return