Module 2 - Creating Alignments

Create Horizontal Alignment (PI Method)

Adjustments to the Horizontal Alignment

Define Start Station for Horizontal Alignment

Horizontal Alignment Annotation

Create Vertical Alignment – Profile (PI Method)

 

Create Horizontal Alignment (PI Method)

Description

In this module the creation of a horizontal alignment with the PI method will be described. There are several methods to create horizontal alignments for more on other methods or other alignment tools please see Bentley's OpenRoads Help – Horizontal Geometry.

If not already open, Open the previously created project alignment file, see Module 1 – Creating Base Models Files; file name (example): HW_CB_1234_1234-Alignments01.dgn.  Make the OpenRoads Modeling workflow active.

1. If not already docked, from the Geometry ribbon select the General Tools tool, select and dock the Design Standards Toolbar and the Feature Definition Toolbar. These tools can be used to better adhere to design standards.

2. From the Design Standards Toolbar: select the AASHTO Design Standards for the project design as needed, example: 6% Super (2 Lane AASHTO Design Standards 2018 – Imperial Design Library) – 35 MPH (2 Lane AASHTO Design Standards 2018 – Imperial Design Library) and Stopping Sight Distance (AASHTO Design Standards 2018 – Imperial Design Library). Turn on the Toggle Active Design Standard. 

3. From the Feature Definition Toolbar: select the active feature definition for Alignment - Center – Centerline and Lock the feature definition. Activate the Chain Command, this will chain the tangents together, but still remain individual elements.

4.  Next from the Horizontal tool group select the Lines – Line Between Points tool. In the Line toolbox, Feature Definition should be set to: Use Active Feature, this should be greyed out, and it will set the feature tangent line to the active feature definition picked in the previous step. In ‘View 1, Default’ select the first PI location. Follow the command prompts attached at the cursor or at the bottom left – Enter Start Point. Example: At the left beginning, at about the middle of the existing roadway – left click.  Enter End Point. Example: somewhere close to the intersection – left click.

5. Because the Chain Command was activated, it prompts Enter End Point. Select a point for the next PI, again it prompts Enter End Point.  Select the end of the horizontal alignment. Right-click to end selecting a new end point, select the Element Section tool to end and get out of the place line command.

 

6. Four PI locations have been established with tangents shown. Turn Off the contours for the terrain.

7. To place a curve (arc) between two tangents select the Arcs – Arc Between Elements – Simple Arc tool. The Simple Arc toolbox opens. The Feature Definition should be set to Use Active Feature. With the Design Standards active the radius is set to the value for the design speed, example: Radius – 654.000’. Now follow the command prompts. Locate First Element – select the first tangent; Locate Second Element – select second tangent; Select Construction Sector with locked Radius 654.00’ – datapoint to select the construction sector; Trim/Extend Option – choose Both and datapoint (left-click) to accept.  

 

8. Repeat this for the next curve (arc).

9. Review the Horizontal Curves. The radii can be adjusted, if the radius doesn’t comply with the design standard an advisory marker will be placed on the radius. 

NOTE:  You still can keep this radius value, just be aware this is not to design standards picked for the alignment. The design standards tools do not have to be used when designing the alignments, the tools are design aides.

10. Complex the horizontal alignment, turn the individual elements into one complex line-string. Select the Complex Geometry – Complex By Element tool.

The Create Complex Element toolbox opens, set the following:

• Method select either: Automatic or Manual, example: Automatic.
• Maximum Gap set to 0.033 (max. distance between elements that will be complexed).
• Feature Definition is set to Use Active features if feature definition is locked or set to as example: Centerline.
• Name type a name for the horizontal alignment, example: RTE A

Follow the prompts: Select First Element – select the beginning of the first tangent, an arrow should appear showing the direction of the alignment. Left Click to accept direction. All of the horizontal alignment should be highlighted/selected. Left Click again to Accept Complex.

 

Adjustments to the Horizontal Alignment

Depending on the Design Intent, the placement and relationship between the elements will control how individual elements of the horizontal alignment can be modified.

For more information on placements and relationship of elements see Bentley's OpenRoads Help.

In the example the PI method was used, this will allow for modifications to the PI locations and the radii of curves.

Adjustment to PI Location and Radii of Curves

1. Using the Element Selection tool click on the horizontal alignment; the horizontal alignment is highlighted and all features of it will be visible. 

2. Select the Second PI location and move it to a new location; see the horizontal alignment move. Move the PI to the new location.

3. Move the third PI location. Select the third PI and move the PI to the new location, move the alignment to better fit with the existing roadway.

4. Now adjust the radius for a better fit.  Increase the first radius to 800 feet, see what happens. Click on the radius, this will activate the radius components that can be adjusted. Click on the radius (orange text) a box with the radius will appear, here change the radius to 800.00’. Press Enter.   Review the arc, click again on the radius and type in 700.00 feet as radius. Click on the second radius, enter a new radius of 400 feet. Press Enter. We will leave this radius to better match in with the existing curve. You can see there is now an exclamation icon, meaning the design standards are not met.

These are just a few of the options to control and edit horizontal alignments, see Bentley's OpenRoads Help for more detailed edit options.

 

Define Start Station for Horizontal Alignment

The Start Station assigns stationing to an element. A station value and a position along the element for that station value are assigned. If no station value is assigned, then the beginning station is assumed to be zero (0+00.00).

1. In the Horizontal toolbar click on the Modify tools – select the Start Station tool.

2. Follow the prompts: Locate Element, select the beginning of the alignment. Start Station Position, enter 0.00 as Start Distance. Enter Starting Station, enter Start Station 100+00.00 and click within the view.

3. Click on the alignment, it will now display the start station and the offset.

Next the alignment needs to be annotated.

NOTE: Any changes to the alignment will also update the Stationing.

Horizontal Alignment Annotation

A Horizontal Alignment needs the following annotation:

• Stationing,
• PC’s, PI’s, PT’s,
• Curve Data and
• Bearings

This has been automated; the annotation will be in the design file (alignment dgn-file) and can be done after the alignment is created. Some text adjustments to location of PC, PI, PT, curve data and bearings can be made, but this should be done sparingly if at all. If adjustments to the alignment are made, the text will also adjust to original text location/placement.

Example: Horizontal Alignment for RTE A (normal annotation) and Private Road (small annotation), see below.

1. Open the alignment file (this file should reside in the Base_Model folder), if not already open. Select the OpenRoads Modeling workflow or the OpenRoads Drawing Production workflow.

2. Click on Drawing Production tab. These annotations tools are available: Annotate Element (for single element), Remove Element Annotation, Model Annotation (for multiple elements) and Remove Model Annotation. As an example, we will use Annotate Element tool.

3. Click the Annotate Element tool, follow the prompts. Locate Elements – Reset To Complete. Click on the alignment (example: SR 14), after it is highlighted, right-click to Reset.

4. The alignment is now annotated/labeled. 

• For alignments using Centerline, Centerline – Green and Centerline – Pink the stationing will be every 50ft. 
• For alignments using Centerline – Small Blue and Driveway the stationing will be every 10 ft.

5. To remove annotation, use the Remove Element Annotation tool, follow the prompts. Locate Elements – Reset To Complete. Click on the alignment, after it is highlighted, right-click to Reset. The annotation is removed.

 

Create Vertical Alignment – Profile (PI Method)

Description

In this module the creation of a vertical alignment (proposed profile) with the PI method will be described. There are several methods to create vertical alignments for more on other methods or other alignment tools please see the Bentley's OpenRoads Help – Vertical Geometry.

1. If not already open, Open the previously created project alignment file, see Module 1 – Creating Base Models Files; file name (example): HW_CB_1234_1234-Alignments01.dgn.

There should be 2 view windows open: View 1, Default showing the survey, terrain and the horizontal alignment; View 2, Default-3D showing the terrain, there are no other 3D items. The 3D terrain should only have the Boundary turned on.

2. If not already docked, from the Geometry ribbon select the General Tools tool and select and dock the Design Standards Toolbar and the Feature Definition Toolbar. These tools can be used to better adhere to design standards.

3. Next open another view window (View 3 Default) for the profile view of the existing terrain at the horizontal alignment, a longitudinal cross section of the existing terrain at the centerline.

4. In the horizontal view (View 1, Default) with the Element Selection tool select the Centerline (the horizontal alignment previously created). Example: RTE A. 

5. Hover over the horizontal alignment for the context menu (pop-up menu) to come up and select the tool. Follow the prompts. Select the Open View (View 3, Default) window. Click within the view and the existing terrain profile will be shown (Terrain must be active). 

6. The view window’s name will also change, example: from View 3, View 3, Profile – RTE A. 

7. The Design Standards previously selected should still be active if previously activated. Example: 6% Super (2 Lane AASHTO Design Standards 2018 – Imperial Design Library) – 35 MPH (2 Lane AASHTO Design Standards 2018 – Imperial Design Library) and Stopping Sight Distance (AASHTO Design Standards 2018 – Imperial Design Library).

8. From the Feature Definition Toolbar: select the active feature definition for Alignment - Center – Centerline and Lock the feature definition. Activate the Chain Command, this will chain the tangents together, but still remain individual elements.

9. Next from the Vertical tool group select the Lines – Profile Line Between Points tool. In the Line toolbox, the Feature Definition should be set to: Use Active Feature, this should be greyed out, and it will set the feature tangent line to the active feature definition picked in the previous step.

10. In "View 3, Profile – RTE A” (example) select the first PI location.  For VPI 1 (Vertical Point of Intersection) you can just click to the beginning of the existing profile, or you can use Civil Accudraw and to use Station and Elevation for the VPI method. Click on the Civil Accudraw icon bring the courser back into the view, now there is Station and ‘Z’ (for elevation) attached to the courser. Type in the Stationing (100+50.00) and hit the Tab key, the ‘Z’ value for elevation can be added or left blank. The view will now show a vertical red line at Station 100+50, snap to the beginning of the terrain and Accept (left click). 

11. Move the courser and pick the next VPI (VPI 2) by Station, Elevation or Distance, example: Station: 109+50, hit the Tab key; you can enter the Elevation, or Tab again, enter a length, or use arrow key to enter a desired slope.

12. Repeat this for VPI 3, example: Station: 115+50, Tab key, enter Elevation 79.00, Tab key. Click the left mouse button to accept and place the VPI.

13. For the last VPI (VPI 4) click to the end of the existing profile or enter a Station, example: Station 117+80, tab (now station is locked) click on the existing profile to match in to.  Click the Right mouse button to stop the command and select the Element Selection tool to fully exit the command.

14. Review your vertical alignment (proposed profile). The Feature Definition Lock and the Design Standard Lock are still on (set).  Making it unnecessary to enter a Feature Definition.

15. Next the vertical curves will be placed. Select the Curves – Profile Curve Between Elements – Parabola Between Elements tool. Follow the prompts.  Locate First Profile Element – click on the first tangent. Locate Second Profile Element – click on the second tangent. Next define the curve by entering the length, example: 300.00 (feet). Accept (left-click), Trim/Extend use the arrow keys to go to Both, Tab key. Accept (left-click). Repeat these steps for the next curve.

16. Review the vertical alignment (proposed profile). Make adjustments if needed.  Using the Element Selection tool click on the first tangent, depending on the rules (relationships) with which the tangent was placed Length, Slope, Station and Elevation can be changed. The Length of Curve can be adjusted.

17. Complex the vertical alignment, select Complex Geometry – Profile Complex By Elements. Set the following: Method to Automatic, Maximum Gap to 0.033. Feature Definition: Use Active Feature (greyed out – Feature Definition locked previously), Name: enter the alignment name – example: RTE A. Follow the prompts. Locate First Element.  Select the beginning of the vertical alignment, the entire alignment will highlight. Accept (left-click).

18. Set the profile active. Using the Element Selection tool, select the profile, from the pop-up menu select: Set As Active Profile. This will associate this profile with the horizontal alignment, and you can now see the alignment also in the 3D view (View 2, Default-3D). Save Settings. 

The profile in the alignment dgn file is not annotated, for annotation of profiles see Volume 13 - Contract Plans and Profile Sheets.