For web reference help on intersection templates and overview, see At-Grade Intersection.

Dataset:

• b4588_ls_tin_071012.dtm
• b4588_rdy.ird
• b4588_rdy.itl
• b4588_rdy.rdp
• b4588_Rdy_cmd.dgn
• jobrdy.gpk
• LY_QC.mcc
• LY_QD.mcc
• proly_qcrdy.iot
• proly_qdrdy.iot
• rddbs\cmjobRDY.alg
• rddbs\cmjobRDY.xml
• rddbs\planGraphics.txt

Modeling At-Grade Intersection

• Exercise 1: Create Surfaces for DTM Features
• Exercise 2: Multicenter Curve Tool
• Exercise 3: Editing COGO Profiles
• Exercise 4: Importing Intersection Alignments
• Exercise 5: Roadway Designer - Create Corridors
• Exercise 6: Modeling Quadrant C
• Exercise 7: Modeling Quadrant D
• Exercise 8: Closing the Gap and Modeling Y Line
• Exercise 9: Modeling Mainline L

Exercise 1: Create Surfaces for DTM Features

• NOTE: Create the proposed roadway DTMs first with superelevation. The edge of pavement information is needed by the Multi-Center Curve program to generate horizontal and vertical controls.

New Surface for Each Corridor: (checked) Empty Design Surface: (checked) Add Transverse Features: (unchecked) Add Exterior Boundary: (unchecked) Features: (unchecked) Components: (unchecked) Action: Apply then Close

* NOTE: This is how the turning radius for quadrant C is determined horizontally.

* NOTE: This is how the turning radius for quadrant C is determined vertically. The proposed edge of travelway profiles from both roads are extracted from the proposed TINs created in the earlier steps.

Step 3.
Click Apply and select the quadrant C in the design file.

* NOTE: This is how the turning radius for quadrant D is determined horizontally.

* NOTE: This is how the turning radius for quadrant D is determined vertically. The proposed edge of travelway profiles from both roads are extracted from the proposed TINs created in the earlier steps.

Step 5.
Click Apply and select the quadrant D in the design file.

Step 6.
Close out of the Multi-Center Curve program.

Exercise 3: Editing COGO Profiles

The generated profiles for the turning radii contain intermediate VPIs with parabolic vertical curves. We need just need the beginning and ending VPIs. To delete the intermediate VPIs, go into COGO, make an input of the each radius profile, and use the editor to remove the intermediate profiles.

Step 1.
Go into COGO. Operator Code is "ot".

Step 2.
.Make input file profile LY_QC by key-in make input file proly_qcrdy.iot pro ly_qc.

Step 3.
Load proly_qc input file. Key-in load proly_qc will also work.

Step 4.
Click on the Editor.

Step 5.
Delete the intermediate VPIs (#2 and 3) and re-number.

Step 6.
Read and Restore to update the GPK.

Step 7.
Resave input file by key-in resave proly_qc.

Step 8.
Repeat steps 2 through 7 for quadrant D. Remember to rename everything from QC to QD.

Exercise 4: Importing Intersection Alignments

Step 1.
Launch Corridor Modelingr.

Step 2.
load the b4588_rdy.rdp file.

Step 3.
load the jobrdy.gpk file.

Step 4.
Add and Import LY_QC and LY_QD to the Geometry.

Step 5.
Resave b4588_rdy.rdp file.

Exercise 5: Roadway Designer - Create Corridors

Step 1.
Launch Roadway Designer and load the b4588_rdy.ird file.

Step 2.
Under Manage Corridors, Add two new corridors for intersection quadrant C and D. Note "Surface Symbology" is optional and does not need to be defined.

Exercise 6: Modeling Quadrant C

Step 1.
Using LY_QC as the active corridor, in the Template Drops dialog box, locate the template LY_QC - C&G RT under the Templates\Intersection folder. Enter the following settings and Add it to the template drop list. Close out of the Template Drops dialog box.

Step 2.
Insert a key template drop where the Y Line intersects the mainline L right EOT. This should be station 5+29.22.

Step 3.
Using Point Controls key-in the following settings to move the template centerline PGL point to intersect the horizontal and vertical location of the mainline right edge of travelway.

Point: PV1_PGL Mode: Both Control Type: Corridor Point Corridor: L Reference Point: RT_PV1_OEOT Start Station: 5+00 Stop Station:5+29.22 Action: Add

• NOTE: To select the Stop station graphically in the design file, hold down the Ctrl button on the keyboard and click on the DP/cross hair button (to the right of the Stop station field). Select "intersection" mode on the snap commands bar and snap to their intersection point. Also since the intersection station is known from the previous step, simply key-in that station.

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Step 4.
Using Point Controls key-in the following settings to move the template centerline PGL point to intersect the horizontal and vertical location of the Y Line centerline and profile.

Point: PV1_PGL Mode: Both Control Type: Alignment Horizontal Alignment: Y Vertical Alignment: Y Start Station: 5+29.23 Stop Station:5+47.82 Action: Add then Close

Step 5.

Smooth Transition for Key Points

Because how sensitive the gutter slopes and paved shoulder slopes are when the centerline PGL point is close to the EOT point, some adjustments have to made to the gutter point and the berm/shoulder break point to provide a smooth transition.

A. Initial State of Template Drop

B. Vertical Adjustment Only for Gutter Slope Point

First compute the elevation difference between the right EOT point and the gutter point for station 5+00 (beginning). This is accomplished by going to the L corridor and navigating to corresponding template drop station at station 5+00 of LY_QC. Corresponding L station should be 17+34.98 and elevation difference should be 0 (flat).

Secondly compute the elevation difference between the right EOT point and the gutter point for station 5+47.82 (ending). It should be -0.09'.

Lastly use these difference in elevation values as point controls. In this step, we want to move the gutter point to an elevation of the profile LY_QC minus the elevation difference at the beginning and ending of the alignment. This will insure a smooth transition of the gutter point throughout the LY_QC corridor.

Point: RT_CG_Top_Gut Mode: Vertical Control Type: Alignment Horizontal Align.: LY_QC Vertical Align.: LY_QC Start Station: 5+00 Stop Station:5+47.82 Vertical Offsets Start: 0.0000 Stop: -0.0900 Action: Add

C. Horizontal Adjustment Only for Berm With

Since the berm width is 10' by default, no adjustment is necessary with parametric constraints.

Step 6.
Click Process All.

Step 7.
Create the surface of LY_QC with the following settings.

Create Surface(s) from: LY_QC New Surface for Each Corridor: (checked) Empty Design Surface: (checked) Add Transverse Features: (unchecked) Add Exterior Boundary: (unchecked) Features: (unchecked) Components: (checked) Action: Apply then Close

The 3D model of the Intersection quadrant C should look like this.

Exercise 7: Modeling Quadrant D

Step 1.
Using LY_QD as the active corridor, in the Template Drops dialog box, locate the template LY_QD - Shld LT under the Templates\Intersection folder. Enter the following settings and Add it to the template drop list. Close out of the Template Drops dialog box.

Step 2.
Add a template drop where the Y Line intersects the mainline L right EOT. This should be station 5+27.38.

Step 3.
Using Point Controls key-in the following settings to move the template centerline PGL point to intersect the horizontal and vertical location of the mainline right edge of travelway.

Point: PV1_PGL Mode: Both Control Type: Corridor Point Corridor: L Reference Point: RT_PV1_OEOT Start Station: 5+00 Stop Station:5+27.38 Action: Add

• NOTE: To select the Stop station graphically in the design file, hold down the Ctrl button on the keyboard and click on the DP/cross hair button (to the right of the Stop station field). Select "intersection" mode on the snap commands bar and snap to their intersection point. Also since the intersection station is known from the previous step, simply key-in that station.

.

Step 4.
Using Point Controls key-in the following settings to move the template centerline PGL point to intersect the horizontal and vertical location of the Y Line centerline and profile.

Point: PV1_PGL Mode: Both Control Type: Alignment Horizontal Alignment: Y Vertical Alignment: Y Start Station: 5+27.39 Stop Station:5+46.95 Action: Add then Close

Step 5.

Smooth Transition for Key Points

Because how sensitive the paved shoulder slopes are when the centerline PGL point is close to the EOT point, some adjustments have to made to provide a smooth transition.

A. Initial State of Template Drop

B. Adjustment for Paved Shoulder Point

First compute the elevation difference between the right EOT point and the paved shoulder point for station 5+00 (beginning). This is accomplished by going to the L corridor and navigating to corresponding template drop station at station 5+00 of LY_QD. Corresponding L station should be 18+16.38 and elevation difference should be 0.23.

Secondly compute the elevation difference between the right EOT point and the gutter point for station 5+46.95 (ending). It should be -0.07.

Lastly use these difference in elevation values as point controls. In this step, we want to move vertically the paved shoulder point to an elevation of the profile LY_QD minus the elevation difference at the beginning and ending of the alignment. Horizontally we are transitioning from a 4' PS to 2'.

Point: LT_PS1_OEOP Mode: Both Control Type: Alignment Horizontal Align.: LY_QD Vertical Align.: LY_QD Start Station: 5+00 Stop Station:5+46.95 Horizontal Offsets Start: -4 Stop: -2 Vertical Offsets Start: 0.23 Stop: -0.07 Action: Apply then Close

Step 6.
Click Process All.

Step 7.
Create the surface of LY_QD with the following settings.

Create Surface(s) from: LY_QD New Surface for Each Corridor: (checked) Empty Design Surface: (checked) Add Transverse Features: (unchecked) Add Exterior Boundary: (unchecked) Features: (unchecked) Components: (checked) Action: Apply then Close

The 3D model of the Intersection quadrant C and D should look like this.

Exercise 8: Closing the Gap and Modeling Y Line

Step 1.
Using the Y corridor as the active corridor, change the Start station for the Y Line corridor to the beginning of the gap by using the Start Station selector button . The new start station for Y should be 10+42.56.

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Name: Y Type: Alignment Horizontal Alignment: Y Vertical Alignment: Y Start Station: 10+42.56 End Station: 12+00 Action: Change then Close

Step 2.
Delete the first two template drops to reset the beginning station template drop.

Step 3.
Add a template drop to the first full template (left and right side) for the Y Line. This station should be 10+43.57.

Step 4.
Edit and delete the left side of the first template drop to remove the part which overlaps the quadrant D templates and corridor.

Step 5.
Click Process All.

Step 6.
Save IRD.

Step 7.
Tie the right side of the Y Line shoulder section to the last C&G section on LY_QC corridor. Control both the paved shoulder point and the grass shoulder point.

Point: LT_SS_Fill_Inf Mode: Both Control Type: Corridor Point Corridor: Y Reference Point: LT_SS_Fill_2to11 Start Station: 5+46.95 Stop Station:5+46.95 Action: Add

Step 8.
Smooth the transition from C&G (LY_QC) to shoulder (Y) by controlling both the paved shoulder point and grass shoulder point on the right side from the beginning station to station 10+60.

• NOTE: The horizontal and vertical offset values are calculated from the template drop start and stop stations.

Point: RT_PS1_OEOP Mode: Vertical Type: Alignment Horizontal Alignment: Y Vertical Alignment: Y Start Station: 10+42.55 End Station: 10+60 Action: Add

Point: RT_GS_OS_CTL Mode: Both Type: Alignment Horizontal Alignment: Y Vertical Alignment: Y Start Station: 10+42.55 End Station: 10+60 Horizontal Offsets Start: 25.0010 Stop: 21.0285 Vertical Offsets Start: 0.5046 Stop: -0.7744 Action: Add then Close

Step 9.
Create the surface of Y corridor with the following settings.

Create Surface(s) from: Y New Surface for Each Corridor: (checked) Empty Design Surface: (checked) Add Transverse Features: (unchecked) Add Exterior Boundary: (unchecked) Features: (unchecked) Components: (checked) Action: Apply then Close

The 3D model of the Intersection quadrant C, D and Y corridor should look like this.

Exercise 9: Modeling Mainline L

Step 1.
When L corridor was first ran, the priority to shear off the right side of the template at the EOT was changed from 19 to 199. This was done to extracted all of the necessary features such as the gutter and paved shoulder points off the mainline L. To reprocess the mainline the priority on the right side to seek the shearline must be set back to 19.

Step 2.
Resync L templates.

Step 3.
Click Process All.

Step 4.
Save IRD.

Step 5.
Create the surface of L corridor with the following settings.

Create Surface(s) from: L New Surface for Each Corridor: (checked) Empty Design Surface: (checked) Add Transverse Features: (unchecked) Add Exterior Boundary: (unchecked) Features: (unchecked) Components: (checked) Action: Apply then Close

The whole intersection model should look like this.