Introduction:

For further details on superelevation, please click on the following web reference link; Superelevation.

Objective:

1. Compute and customize superelevation for a simple curve on a 2-lane roadway undivided facility.
2. Compute and customize superelevation for a curve with spirals on a 6-lane roadway divided facility.
3. Print out superelevation report.
4. Verify the superelevation layout according to standards.

Dataset:

• 10_Superelevation_with_Roadway_Designer.pdf
• jobrdy.gpk
• r2011.ird
• r2011.rdp
• r2011_ex.dtm
• r2011_rdy_itl
• r2011_rdy_dsn.dgn
• rddbs\cmjobRDY.alg
• rddbs\cmjobRDY.xml

Exercises Summary:

• Exercise 1 - Superelevation on 2-Lane Undivided Facility
• Exercise 2 - Superelevation on 6-Lane Divided Facility
• Exercise 3 - Printing Superelevation Reports
• Exercise 4 - Compute and Verifying Superelevation Layout

Exercise 1: Superelevation on 2-Lane Undivided Facility

Table: 08_40.sup* %Runoff on Tangent: 66.666667%** Interpolate Table Values: checked Transition Lengths Are: Runoff Update Geometry from Table: checked Design Speed: 40 (Prompt after clicking Load Values From Table with Update Geometry from Table checked.) Action: Load Value From Table then Next * NOTE: The superelevation tables (.sup) can be found in the Roadway Workspace. "C:\NCDOT_V8_WORKSPACE\ROADWAY_STDS\ English\geopak\Corridor_Modeling\Super_Data\ AASHTO 2004\imperial\" ** NOTE: Even though the value is rounded to the nearest even percent (67%), it is only for display purpose only. A precise figure of 66.666667% should always be entered to represent 2/3 of the runoff length on a tangent segment.

Step 9.
Enter the following settings for the Superelevation Section Definitions dialog box.

• NOTE: Defining the left and right sides. Adjust the superelevation rate and runoff lengths to have "even increments" if desired.

  1. Add Superelevation Section - Sections

  

  Name: Y9 Crown Point: PV1_PGL Left Range Point: LT_PV1_OEOT Right Range Point: RT_PV1_OEOT Pivot Direction: From Crown Point Number of lanes: Two Runoff Length Multiplication Factor: 1.0000 Action: OK

   

 

2. Superelevation for Selected Section: Edit

Curve 1 Full Superelevation Rate: 7.0% Runoff Length(s): 140 Action: Apply then Next

 

Curve 2 Full Superelevation Rate: 8.0% Runoff Length(s): 172 Action: Apply then Next

 

Curve 3 Full Superelevation Rate: 8.0% Runoff Length(s): 172 Action: Apply then Close

Action: Next

Action: Finish

When prompted to "Fix Superelevation Overlap", click Close. We will be editing the superelevation sections in Roadway Designer Superelevation Mode in the next step.

Step 11.
Activate Superelevation Mode in Roadway Designer.

Step 12.
Modifying Overlaps
In the Superelevation Diagram View, delete the two middle points at the 0.00 superelevation rate line on the second curve set (around station 20+50) by right mouse clicking anywhere in the view and select Delete Points. Place a fence around the two points to delete them.

• TIP: Undo can be done by right mouse click anywhere on the view and select Edit Curve Set Stations and click on Undo.

Step 13.
Delete the two side points of the high side (red line) at station 20+07.24 and 20+94.55 by right mouse clicking on the point and select Delete Point.

Step 14.
Delete the extra point on the low side (yellow line) at station 20+94.35.

Step 15.
Fully constrained the two bottom points by Mirror Cross Slope the top superelevation points. Right mouse click on the point and choose Edit.

Constraint 2 Type: Mirror Cross Slope Parent 1: Y9 PV1_PGL-LT_PV1_OEOT-20+14 Action: Apply the Close

Constraint 2 Type: Mirror Cross Slope Parent 1: Y9 PV1_PGL-LT_PV1_OEOT-20+94 Action: Apply the Close

This is what the modified superelevation diagram should look like between curve 1 and curve 2.

Step 16.
Modifying Superelevation Rate and Moving Superelevation Key Points for Reverse Curves

Below is a customized layout of the superelevation through the reverse curve. Start of full super of 0.04 at station 22+91.03 on Curve 2 with increments of 17'. Zero cross slope is located on the point of reverse curve (PRC) station 23+59.03. Full super of 0.04 is obtained on Curve 3 at station 24+27.03.

Edit superelevation point Y9 PV1_PGL-LT_PV1_OEOT - 22+23 (Curve 2 on top red line).

Step 17.
Change the cross slope of this point from 8.0% to 4.0%.

Cross Slope: 4.0% Action: Apply then Close

Step 18.
Move superelevation point Y9 PV1_PGL-LT_PV1_OEOT - 23+02 (Curve 2 on top red line) to station 22+91.03 by editing it.

Station: 22+91.03 Action: Apply then Close

Step 19.
Move superelevation point Y9 PV1_PGL-LT_PV1_OEOT - 24+41 (zero percent cross slope between Curve 2 and Curve 3 on middle yellow line) to the PRC station 23+59.03 by right mouse click on the point and select Move Point. Key in following settings when prompted.

Station: 23+59.03,0% Action: Enter (Keyboard)

Step 20.
Edit superelevation point Y9 PV1_PGL-RT_PV1_OEOT - 24+16 (Curve 3 on top yellow line).

Step 21.
Change the station to 24+27.03 and the cross slope from 8.0% to 4.0%.

Station: 24+27.03 Cross Slope: 4.0% Action: Apply then Close

Step 22.
Edit superelevation point Y9 PV1_PGL-RT_PV1_OEOT - 22+77 (zero percent cross slope on middle yellow line) by right mouse click on the point and select Edit Point. Key in following settings when prompted.

Station: 23+59.03 Cross Slope: 0.0% Type: Undefined Non-Linear Curve Length: 0.0000 Constraint 1 Type: None Constraint 2 Type: None Action: Apply then Close

Step 23.
Delete the outside normal crown superelevation points (circled in red). There should be a total of three deleted points, one on the left side of the PRC and two (on top of one another) on the right side of the PRC.

This is what the final superelevation diagram should look like at the PRC.

This is what the final superelevation diagram should look like for the entire corridor.

Exercise 2: Superelevation on 6-Lane Divided Facility

Table: 10_70.sup* %Runoff on Tangent: 66.666667%** Interpolate Table Values: checked Transition Lengths Are: Runoff Update Geometry from Table: checked Design Speed: 70 (Prompt after clicking Load Values From Table with Update Geometry from Table checked.) Action: Load Value From Table then Next * NOTE: The superelevation tables (.sup) can be found in the Roadway Workspace. "C:\NCDOT_V8_WORKSPACE\ROADWAY_STDS\ English\geopak\Corridor_Modeling\Super_Data\ AASHTO 2004\imperial\" ** NOTE: Even though the value is rounded to the nearest even percent (67%), it is only for display purpose only. A precise figure of 66.666667% should always be entered to represent 2/3 of the runoff length on a tangent segment.

Step 9.
Enter the following settings for the Superelevation Section Definitions dialog box.

• NOTE: Defining the left and right sides. Adjust the superelevation rate and runoff lengths to have "even increments" if desired.

  1. Add Superelevation Section - Sections

  

  Name: LT_L_SE Crown Point: LT_PV1_PGL Left Range Point: LT_PV1_OEOT Right Range Point: LT_PV1_PGL Pivot Direction: From Crown Point Number of lanes: Four Runoff Length Multiplication Factor: 1.3300 Action: OK

Name: RT_L_SE Crown Point: RT_PV1_PGL Left Range Point: RT_PV1_PGL Right Range Point: RT_PV1_OEOT Pivot Direction: From Crown Point Number of lanes: Four Runoff Length Multiplication Factor: 1.3300 Action: OK

 

2. Superelevation for Selected Section: Edit

Curve 1 Full Superelevation Rate: 5.0% Start-Use Spiral Length (300.00): checked Stop-Use Spiral Length (300.00): checked Action: Apply then Next

 

Curve 2 Full Superelevation Rate: 4.0% Start-Use Spiral Length (250.00): checked Stop-Use Spiral Length (250.00): checked Action: Apply then Next

 

Curve 3 Full Superelevation Rate: 4.0% Start-Use Spiral Length (250.00): checked Stop-Use Spiral Length (250.00): checked Action: Apply then Next

 

Curve 4 Full Superelevation Rate: 4.0% Start-Use Spiral Length (250.00): checked Stop-Use Spiral Length (250.00): checked Action: Apply then Next

 

Curve 5 Full Superelevation Rate: 4.0% Start-Use Spiral Length (250.00): checked Stop-Use Spiral Length (250.00): checked Action: Apply then Next

 

Curve 6 Full Superelevation Rate: 5.0% Start-Use Spiral Length (300.00): checked Stop-Use Spiral Length (300.00): checked Action: Apply then Next

 

Curve 7 Full Superelevation Rate: 4.0% Start-Use Spiral Length (410.10): checked Stop-Use Spiral Length (410.10): checked Action: Apply then Close

Action: Next

Action: Finish

Exercise 3: Printing Superelevation Reports

Step 8.
Generate a Superelevation Data report by keying in the following settings in the Roadway Designer Superelevation Report dialog box.

Report At: All Processed Stations Available Superelevated Points: All Include Control Line Definitions: checked   Action: Apply

Step 9.
The Superelevation Data report can be viewed through the Bentley Civil Report Browser by selecting the SuperelevationData.xsl (Extensible Stylesheet Language) item in the Superelevation folder.

Step 10.
The Superelevation Data report can be printed through the Bentley Civil Report Browser by selecting the Print command under File menu item. The report can also be save under the File menu item (Save As).

Step 11.
Close out of the Bentley Civil Report Browser.

Step 12.
Generate a Superelevation Station report by keying in the following settings in the Roadway Designer Superelevation Report dialog box.

Report At: Specified Interval (50.0000) Include Superelevation Events Points: checked Available Superelevated Points: All Include Control Line Definitions: checked   Action: Apply

Step 13.
The Superelevation Station report can be viewed through the Bentley Civil Report Browser by selecting the SuperelevationStations.xsl (Extensible Stylesheet Language) item in the Superelevation folder.

Step 14.
The Superelevation Station report can be printed through the Bentley Civil Report Browser by selecting the Print command under File menu item. The report can also be save under the File menu item (Save As).

Step 15.
Close out of the Bentley Civil Report Browser and close out of the Roadway Designer Superelevation Report dialog box.

Exercise 4: Compute and Verifying Superelevation Layout

Radius: 800'
Design Speed: 40 MPH
e max: 8%

Step 2.
Compute the runoff length using the Maximum Relative Gradient formula for Curve 1 Chain -Y9-. Curve 1 has these properties:

Maximum Relative Gradient, Percent: 0.58 (pg. 177)
Number of Lanes Rotated: 1
Adjustment Factor for Number of Lanes Rotated: 1 (pg. 178)
Width of One Traffic Lane: 12'
Design Superelevation Rate, Percent: 7.0

The expression to determine the minimum length of runoff using the Maximum Relative Gradient is described below (pg. 179).

Lrunoff = (12*7)/0.58=144.83'

Step 3.
Verify computed runoff length with the AASHTO 2004 Green Book and the Roadway Designer Superelevation Table (08_40.SUP).

Green Book (40 MPH, 1 Lane Rotated, 7.0% SE Rate): 145
08_40.SUP (.070 Super Rate, 2-lane spl lgt): 145

Step 4.
Download the superelevation layout spreadsheet to help determine the placement and the even increment stations of Curve 1. Enter the following settings for Curve 1 in the NCDOT Superelevation Layout dialog box.

Curve Name: Y9-Curve1 Transition Type: Curve PC Station: 10+93.62 PT Station: 19+61.01 Facility Type: Undivided Curve Direction: Right e Design (%): 7 Runoff Length: 140 Action: Draw NOTE: The tangent runout length and increment values are automatically calculated when the runoff length and e design figures are entered.

Step 5.
Compare the superelevation layout spreadsheet with the Superelevation Station Data report for Curve 1. Note the Curve Exit side of Curve 1 has been modified to hold the removed crown/reverse crown superelevation to Curve 2.

How the Superelevation Transition was Determined for Curve 1

Runoff Length = 140
1/3 of Runoff Length = 46.67
Relative Gradient Slope (%) = 140/7 = 20

PC Station = 10+93.62
Beg FS Sta = 10+93.62 + 46.67 = 11+40.29 (Full Super)
0% Cross Slope Sta = 11+40.29 - 140 = 10+00.29 (Runoff)
Normal Crown Sta = 10+00.29 - 2(20 (RGS)) = 9+60.29 (Tangent Runout)

PT Station = 19+61.01
End FS Sta = 19+61.01 - 46.67 = 19+14.34 (Full Super)
0% Cross Slope Sta = 19+14.34 + 140 = 20+54.34 (Runoff)
Normal Crown Sta = 20+54.34 + 2(20 (RGS)) = 20+94.34 (Tangent Runout)

The above procedure can be repeated for curve spirals transitions. For further details of superelevations, see the Roadway Web Help.