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Reinforce Concrete Box Culverts (RCBC)
Introduction:
For further details on the culvert components, please click
on the following web reference link; Culvert.
Three items are required in COGO to proceed with the culvert
corridor.
- A horizontal alignment for each culvert stored in the GPK.
- The bottom culvert elevation below the the roadway centerline (Hydro's
Culvert Report)
- The proposed grade/slope of culvert (Hydro's Culvert Report)
Once number 2 and 3 are known, an extrapolated profile for
each culvert can be set using point controls. Note the box height and
width given in Hydro's Culvert Report are the inside opening dimensions
of the box.
Objective:
The design calls for a 8'(wide) x 9' (tall)
x 60' (long) triple barrel RCBC at a 130 degrees skew.
Create a culvert DTM and generate cross sections with the roadway templates.
Dataset:
Video - Coming Soon
(Right-click on the video and select "Play" to play or pause
the video)
Download dataset here... Misc_Culvert
(293 KB)
-
NOTE: The content of the ZIP dataset
file must be extracted to the root C:\ directory.
Each chapter is then automatically expanded to the "C:\NCDOT
Training\Roadway\CM" folder. This folder structure
must be maintain to insure all saved ITL, DTM,
and RDP paths are set accordingly.
Content:
- b4824.rdp
- b4824_ls_tin.dtm
-
b4824_rdy.ird
- b4824_rdy.itl
- b4824_Rdy_cmd.dgn
- b4824_rdy_dsn.dgn
- b4824_rdy_xsc.dgn
- jobrdy.gpk
- rddbs\cmjobRDY.alg
- rddbs\cmjobRDY.xml
- rddbs\planGraphics.txt
Exercise: Modeling Culverts
Step 1.
While in the file b4824_rdy_cmd.dgn, launch
Corridor Modeling.
Step 2.
Load the file b4824.rdp preference file.
Step 3.
Load the jobrdy.gpk file.
Step 4.
Launch Roadway Designer.
Step 5.
In Roadway Designer, load the
b4824_rdy.ird file.
Step 6.
Create the surface of the L corridor.
Enter the following setting in the Create Surface
dialog box.
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NOTE: Create the proposed roadway
DTM first.
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| 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 |
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Step 7.
In the same IRD, create a new corridor. Enter the following
settings in the Manage Corridors dialog box.
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NOTE: Create the culvert
corridor to run underneath the proposed roadway. A vertical
alignment (profile) is not required. We will be using Point
Controls to place the culvert at the appropriate elevation.
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| Name: Culvert_1
Surface Symbology: Surface Symbology
Cyan
Type: Alignment
Horizontal Alignment: CV_1
Vertical Alignment: None
Pi Rounding Tangent: 0.0000
Action: Add then Close |
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Step 8.
Enter the following settings for the Template Drops
dialog box.
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Corridor: Culvert_1
Station: 5+00
Interval : 5
Template: 3 RCBC - Triple Barrel
Action: Add then Close |
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NOTE: Initially the template is located at
the (0,0) mark. We will use Point Controls to move the template
to the proposed culvert elevation.
Step 9.
Enter the following settings for the Point
Controls dialog box.
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Point: RCBC_PGL
Mode: Vertical
Control Type: Elevation and Grade
Elevation: 435.71*
Grade: -0.5%*
Start Station: 5+00.00
Stop Station: 5+60.00
Action: Add then Close |
* NOTE: The elevation and grade values were computed
from Hydro's Culvert Report. |
NOTE: Now the template is moved to the right elevation.
Parametric Constraints (CV_Box Height and CV_Box
Width) can used to control each of the barrel's height and width.
Since the template default width is 8' and height is 9', we will not need
to adjust these values for this exercise.
Step 10.
Process All template drops.
Step 11.
To view the proposed surface above the culvert, use Target
Aliasing. Add the alias Surface - L
and Close out of the Target Aliasing
dialog box.
 
Step 12.
Create the surface of the Culvert_1 corridor.
Enter the following setting in the Create Surface dialog
box.
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| Create Surface(s) from: Culvert_1
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 |
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Step 13.
Switch back to the L corridor.
Step 14.
To view the top surface of the culvert below the roadway, use
Target Aliasing. Add the alias Surface
- b4824_ls_tin first and then the alias Surface - Curvert_1.
Click OK to close out of the Target Aliasing
dialog box.
Step 15.
Save the IRD file and close out the b4824_rdy_cmd.dgn
file.
Drawing both the proposed roadway template and the culvert underneath
in the cross section file.
Step 16.
Open the file b4824_rdy_xsc.dgn.
Step 17.
Activate the Geopak Draw Cross Sections from Surfaces
dialog box.
Step 18.
Enter the following settings in the XS Cells
tab.
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| Job Number: RDY
Chain: L
Pattern: By Station
Begin Station: 13+00
End Station: 17+50
Even: 10
Left Offset: 75
Right Offset: 75
Action: Surfaces Tab |
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Step 19.
Add the following DTM files in the Surfaces
tab. Remember the only DTM file that needs the symbology defined is the
existing ground DTM (b4824_ls_tin.dtm).
- b4824_ls_tin.dtm
- L.dtm
- Culvert_1.dtm
Step 20.
Draw cross sections.
NOTE: Depending on the skew of the culvert in relationship
to the roadway centerline, the number of barrels are visible. Since the
culvert for this exercise is skewed at a 130 degree angle, all three barrels
are visible on a couple of cross sections. For a 90 degrees skew, only
the top and bottom slabs of the culvert is visible (or a single span wall
for double and quadruple barrel RCBC).
In the future exercises we will be going over different methods used
to clip the road side slopes with the culvert wing walls and top face
openings.
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NC DOT
NC DOH
NC GOV
