Create/Edit Cul-de-sac
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Create/Edit Cul-de-sac

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Introduction

The Create/Edit Cul-de-sac command is a powerful routine to automate the process of creating cul-de-sacs. 

Once created the Cul-de-sac profile can be edited immediately via the Vertical Grading Editor.  Part of the cul-de-sac from the start and end of the alignment will obtain elevations from the connecting Road String cross sections.

Special Notes on Cul-de-sac Templates - Template Details

Special Notes: Users must first create the Road to which the cul-de-sac is connected.  Use the Create/Edit Roads command to first create and profile the incoming Road.
  For Civil 3D Users, alignments created can include an alignment description with the prefix cds- (not case sensitive).

For Non-Civil 3D Users, alignments should be be created as Type 'Cul-de-sac'.
 

The direction of the cul-de-sac alignment is worked out as the OPPOSITE of the Active Drawing Settings Kerb Direction.  This happens because the required direction is the direction that you would drive around the cul-de-sac (and this changes for left and right hand drive situations).  Confirming direction for creating your cul-de-sac alignments:

  • If you drive on the left side of the road, the alignment must be created in a Counter Clockwise direction. 
  • If you drive on the right side of the road, the alignment must be created in a Clockwise direction.
  The data used to create the horizontal geometry is stored, so that it is easy to adjust the shape of the cul-de-sac.

For Civil 3D Users, using the command Update all Road Objects will move the cul-de-sac alignment if the incoming road is moved or widened.

For Non-Civil 3D Users, the adjustment of the cul-de-sac will largely be automatic.  The above command can be used if required.

ALWAYS extend the Road beyond the end of the cul-de-sac - the software uses the road levels to automate the profile of the cul-de-sac, and will trim back the Road at the time of:

Details

This command can be used to Create as well as Edit a cul-de-sac.  The form suppresses some functionality in the edit mode.

Creating/Editing a Cul-de-sac

Upon starting the command the command prompt reads:

Select Cul-de-sac to Edit [Enter if Creating a New Cul-de-sac Alignment]

Options are:

Once the alignment is selected or the [Enter] button is pressed, the following form is displayed.  Hover over the different inputs to see the central diagram and supporting notation update:

 

Main Processes

The main processes for creating/editing a cul-de-sac is as follows:

  1. Cul-de-sac definition and connectivity established
  2. Cul-de-sac horizontal geometry parameters set
  3. Create/Update cul-de-sac (Alignment) geometry
  4. Set profile controls for the cul-de-sac interaction with the incoming Road

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Step 1: Cul-de-sac Definition

A number of options are provided at the top of the form for the user to define the cul-de-sac name and connectivity to the Road, as follows:

For a new cul-de-sac, users need to define:
Cul-de-sac Name This is the name that will be assigned to the new Road element created in Civil Site Design, as well as the name of the alignment that will be created.
Incoming Road Use the pick list to select a Road for the cul-de-sac to connect to.
Attachment In order to get the alignment direction correct, the user must select whether the alignment is being created near the Start or the End of the alignment.  This option is initially completed automatically based on the nearest end where the user clicked to select the the road aligment, but can be over-ridden with the Start or End button afterwards.
Match to Code Civil Site Design automates the horizontal alignment creation of the cul-de-sacs by locating a particular code from the Road.  This code normally defines the edge of the roadway, and sets where the cul-de-sac alignment should connect.

Use the pick list to select the appropriate Code from the incoming Road cross section.

A sketch demonstrates the different aspects of these options:

For an existing cul-de-sac that is being edited, the Cul-de-sac Name parameter is greyed out and unable to be edited.

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Step 2: Setting the Horizontal Design Parameters

There are a number of different horizontal design options for the cul-de-sac.  For each of these options (excepting the Specify Alignment), the user is able to type in radii and length values and specify/pick setout geometry points.  The software will use this information directly to build an alignment and use this for creating the cul-de-sac.

Cul-de-sac configurations are shown below.  Simply click on one of the buttons from the image below for further information on that design method:

Circular Cul-de-sac

This method of creation requires the user to select a Start Chainage and three Radii (approach Radius, bowl radius and return Radius).

As an alternative to specifying the Start Chainage users could tick the box to specify a Pass Through point in the bowl of the cul-de-sac.  If the pass through point is selected, the position of the cul-de-sac alignment is adjusted so that this point lies on the new cul-de-sac alignment.  If it is impossible to have the cul-de-sac alignment pass through this point, then an error message is issued.

Double click in the Start Chainage cell or click on the icon to select a Starting Chainage off screen.  Click on the select icon to graphically locate the Pass Through point.

Start Chainage Specify the Starting Chainage by typing in the box, or click on the icon to select a Starting Chainage off screen. Distance is measured along the Incoming Road.
Radius 1 Enter the Approach Radius
Radius 2 Enter the Bowl Radius
Radius 3 Enter the Return Radius
Offset Enter a value (positive or negative) to offset the centre of the cul-de-sac. Measured perpendicularly from the Main Road Centreline.
Note: the maximum offset must be less than Radius 2 minus the road lane width (C.L. code to the Edge Code that the cul-de-sac connects to)
Use Pass Through Tick the box to specify a Pass Through Point in the bowl of the cul-de-sac. Click on the icon to select a Pass Through Point off screen.

Note: If the pass through point is selected, the position of the cul-de-sac alignment is adjusted so that this point lies on the new cul-de-sac alignment.  If it is impossible to have the cul-de-sac alignment pass through this point, then an error message is issued.

By Center (Version One) - Circular Cul-de-sac

As above, except that a Centre Point is specified for the court bowl, instead of a Start Chainage.  The Centre Point is determined from the selection of an arc in the drawing.

Radius 1 Enter the Approach Radius
Radius 2 Enter the Bowl Radius
Radius 3 Enter the Return Radius
Tangent 1 Type in a Tangent length. Leave at 0 to omit a tangent.
Tangent 2 Type in a Tangent length. Leave at 0 to omit a tangent.
Centre Point This is determined from the selection of a circle or arc in the drawing. The Centre Point will be located at the centre of the circle or arc.

Click the icon to graphically locate the centre of the cul-de-sac from the drawing.

By Centre (Version2) - Asymmetric (Club Foot) Cul-de-sac

As above, except that setout of the bowl is made by selecting the centre point of the bowl. The Centre Point is determined from the selection of an arc in the drawing.

Radius 2 Enter the Approach Radius
Centre Point This is determined from the selection of a circle or arc in the drawing. The Centre Point will be located at the centre of the circle or arc.

Click the icon to graphically locate the centre of the cul-de-sac from the drawing.

Asymmetric (Club Foot) Cul-de-sac

The cul-de-sac bowl is offset so that it bulges out one side only.  An additional pick box will display for the user to select LEFT or RIGHT side for the bulge.

Select the Starting chainage, approach radius and bowl radius.

Start Chainage Specify the Starting Chainage by typing in the box, or click on the icon to select a Starting Chainage off screen. Distance is measured along the Incoming Road.
Radius 1 Enter the Approach Radius.
Radius 2 Enter the Bowl Radius.
Use Pass Through Tick the box to specify a Pass Through Point in the bowl of the cul-de-sac. Click on the icon to select a Pass Through Point off screen.

Note: If the pass through point is selected, the position of the cul-de-sac alignment is adjusted so that this point lies on the new cul-de-sac alignment.  If it is impossible to have the cul-de-sac alignment pass through this point, then an error message is issued.
Asymmetric Side
Left Select to have the bulge appear on the left side of the cul-de-sac.
Right Select to have the bulge appear on the right side of the cul-de-sac.

Straight T Cul-de-sac

As described below.  Ensure that reasonable figures are set here otherwise a message will display advising that there is no geometric solution.

Start Chainage Specify the Starting Chainage by typing in the box, or click on the icon to select a Starting Chainage off screen.  Distance is measured along the Incoming Road.
Offsets Enter offset distances measured from the points specified in the above diagram.  As you hover over the different entries, the supporting image will update to show you which length dimension (L) you are editing.  Values must be greater than 0.01m.
Radii Enter the radii of curves as specified in the above diagram. As you hover over the different entries, the supporting image will update to show you which radius dimension (R) you are editing.  Values must be greater than 0.01m.

Curved T Cul-de-sac

As described below.  Ensure that reasonable figures are set here otherwise a message will display advising that there is no geometric solution.

Start Chainage Specify the Starting Chainage by typing in the box, or click on the icon to select a Starting Chainage off screen. Distance is measured along the Incoming Road.
End Chainage Specify the End Chainage by typing in the box, or click on the icon to select an End Chainage off screen. Distance is measured along the Incoming Road.
Offsets Enter offset distances measured from the points specified in the above diagram. Values must be greater than 0.01m.
Radii Enter the radii of curves as specified in the above diagram. Values must be greater than 0.01m and less than the adjacent Offset length.  For example, R2 must be less than L2.
Angles Enter the angles (in degrees) measured from the Main Road Alignment.  Angle #1 for the left leg and angle #2 for the right leg.

 

Use Alignment

Designers are able to create their own alignment for the cul-de-sac.  In order for this to be successful the Designer must:

Use the pick list to select the required alignment in the drawing to use for the cul-de-sac horizontal geometry.  All Alignments will be listed in the pick list.  Cul-De-Sac Alignments already created or defined as a 'Cul-De-Sac' (in CAD versions, users set the alignment Type, and in Civil 3D users can type cds- in the Alignment Description field) will appear at the top of list and will be separated from all other alignments available by a couple of blank lines.

Specify Cul-de-sac Alignment Select the cul-de-sac alignment from the list.
Centre Point X Specify the X value for the centrepoint of the bowl radius of the cul-de-sac (or approximate in the case of a non-circular cul-de-sec) by typing in the box, or click on the icon to select the centrepoint coordinates.
Centre Point Y Specify the Y value for centrepoint of thebowl radius of the cul-de-sac (or approximate in the case of a non-circular cul-de-sec) by typing in the box, or click on the icon to select the centrepoint coordinates.

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Horizontal and Vertical Geometry Creation - Commands

After setting the desired horizontal geometry parameters users proceed to the Create/Update Alignment function for the cul-de-sac and then undertaking a profile design including assignment of a Template (unless in Edit mode).


Step 3: Creating the Horizontal Geometry
Create/Update Alignment Click to generate an Alignment for the cul-de-sac based on the displayed cul-de-sac design parameters and connection details defined on the left of the form.  This will create an Alignment connected to the selected Road at the specified connection point at the start and end of the cul-de-sac alignment.

Note: The initial display and label style applied (when the alignment is created) is set from the Active Drawing Settings form.

If the alignment is not appearing as desired, simply change the parameters defining the horizontal geometry and click on the Create/Update Alignment button again to recreate the alignment.

Step 4: Creating the Vertical (Profile) Geometry
String Creation Clicking theCreate/Update Alignment button will activate the String Creation tools and update the information in the fields for the chainage data on the incoming road.  Until a valid Alignment design is created, this side of the form will be inaccessible and greyed out.
Chainage Data on Incoming Road Provides the user with information about the horizontal geometry of the cul-de-sac with reference to the Road alignment chainages.
  Start Chainage Describes the Incoming Road chainage at the Start of the cul-de-sac alignment.
  End Chainage Describes the Incoming Road chainage at the End of the cul-de-sac alignment.
  Centre Point Chainage Describes the Road chainage at the centre point of the arc defining the head of the cul-de-sac.

Note: This value has little relevance when the horizontal geometry is not designed with a single arc defining the head of the bowl.
  Centre Point Offset Describes the offset of the centre point of the arc defining the head of the cul-de-sac, measured perpendicular to the Road centreline alignment.
String Creation This panel contains the controls for the application of automatic design tools to be applied to the cul de sac.
  Template Use the pick list to assign an appropriate cross section template to the cul-de-sac.

Users can set the Template to 'Auto' - this will force the software to automatically generate a cross section based on label data found at the start and end of the cul-de-sac.  The default batters and subgrade template are inherited from the Active Drawing Settings.  Use the Design Data Form to further adjust it.

Note: Users will not be able to click on Create/Update String until a Template is defined.  

Special Notes on Cul-de-sac Templates - see Template Details

When editing a created cul-de-sac, this field will be greyed out.  Further Template changes would be done though the Design Data Form
  Section Spacing  Sets the distance between the automatic IPs assigned to the cul-de-sac profile.
  Omit Batters/Daylight  Check this box to not apply any Batter/Daylight override to the cul-de-sac.  This option may be required when the batter code strings (BAT) cross due to a combination of a small radius, a flat batter slope and a large cut or fill to the existing surface, or when a Template is selected that includes batter control/s. 
  Automatic Design Civil Site Design can automate the profile design to ensure connection to the incoming Road and matching to Road cross section grades, as well as controlling the extents of the Road centreline profile into the cul-de-sac.
    Calculate levels To 
Starting from the START of the cul-de-sac alignment and moving in a forward direction along the alignment, automatically assign IPs to the cul-de-sac profile UP TO the Chainage value set here (chainage defined relative to the incoming Road chainages).

Note: Designers are NOT able to edit these 'automatic' IPs in the Template Editor (shown below).  The ONLY way to remove these is to edit the 'Transfer Levels to' chainage.
    Centreline End Point 
Type in the incoming Road chainage to extend the Road centreline to when designing the cul-de-sac.  A crown breakline will be inserted into the Auto Model surface up to the user defined chainage.

Note: It is unusual to extend the crown beyond the centre point of the cul-de-sac and the terrain model gives unpredictable levels if the crown point is extended beyond the end of the cul-de-sac.
         This input will be greyed out if 'Omit Pavement Code' is unticked.
    Calculate Levels To 
Starting from the END of the cul-de-sac alignment and moving in a reverse direction along the alignment, automatically assign IPs to the cul-de-sac profile UP TO the Chainage value set here (chainage defined relative to the incoming Road chainages).

Note: Users are NOT able to edit these 'automatic' IPs in the Vertical Grading Editor (shown below).  The ONLY way to remove these is to edit the 'Transfer Levels to' chainage.
  Additional Options  Use these options to apply additional control to the cul-de-sac sections and model.
Omit Pavement Code By default, the software will project a Code (RDUM or LDUM pending the cul-de-sac direction) from the design CL of the cul-de-sac to the elevations of the Road centreline.  This defines the 'pavement' of the cul-de-sac and enables the inclusion of pavement materials in the cross sections of the cul-de-sac string. 
There are many geometric cases where the LDUM/RDUM code cannot project to the Road centreline and can give unusual results, for which there is the option to omit the pavement code (not create the LDUM/RDUM code).
Slope to Offset Center Point (%) The levels on the breakline to the centre point are computed from the incoming road Centre Point Chainage level. The actual level of the centre point can be adjusted by setting this crossfall. If this % slope is zero, then the centre point level is the same as at the Centre Point Chainage. If the value is non zero, then the level is adjusted by the (%slope).

Note: (Centre Pt Offset). If you use a non zero value, then you must check the centre point level on the terrain model to make sure it is what you require.
Create/Update String Click on this button to compute and refresh the vertical grading if values in the form have changed.
Reset Design Flag The software will automatically design the IPs to smoothly transition the cul-de-sac profile between the set IPs. Reset Design Flag enables the designer to change the controls between the set IPs.

Upon selecting the command the following form is displayed:

Automatic Re-Design Have the software automatically redesign the internal section of the profile when computing the VC for the cul-de-sac.
Keep Internal Design The software does not alter any IPs in the central region of the cul-de-sac that have been set by the user.
Keep Internal Design and Match Grades Designer has control of the profile with the software matching the incoming and outgoing grades.
Apply and Exit Save changes and exit the form.
Cancel Exit the form without saving any changes.
Set Section Widths This enables the user to set the display widths left and right of the alignment, which impacts the Cross Section View in the Vertical Grading Editor. 

Upon selecting the command the following form is displayed:

Left Width Enter the width of the display left of the alignment.
Right Width Enter the width of the display right of the alignment.
OK Apply changes and exit the form.
Cancel Exit the form without saving any changes.
Show VGE on Close Click this check box on to display the Vertical Grading Editor upon closing this form.  This will enable immediate review/editing of the cul-de-sac string design.  

Click here for more information regarding design using the Vertical Grading Editor.
Close Click here to exit the form, with or without having created a Cul-de-sac in the software.
Click on this button to enable zooming and panning in the drawing window using the middle mouse scroll button. Press [enter] or [esc] to cancel the zoom/pan and return to the form.