Section 3 - Laying Out Drainage
The user should view the QuickStart - Laying out a Drainage Network in OpenRoads Designer from the Bentley LearnServer website to become familiar with the tools.
Creating a drainage DGN-file using the 2D seed as described in Section 2 - Getting Started will allow for the availability of the CTDOT Drainage feature definitions such as feature symbology, level, element templates and annotations.
Drainage and Utilities feature definitions files:
- CV_SUDA_Features_Levels_ElemTemp.dgnlib
- CV_SUDA_SVY_Features_Levels_ElemTemp.dgnlib
These feature definition files will be updated as needed to incorporate changes in the CTDOT standards. Should the designer find an item changed or was added (example: new wing wall) please bring this to the attention of AEC Applications.
PLACE NODE
Turn off the Fill in View Attributes to only see the outline of structures (catch basin, etc.), this will help when placing nodes and conduits.
1. Select the Place Node command to lay out your drainage structures: catch basins, endwalls, etc.
2. Select the Feature Definition (example: Type “C” CB à C CB - 6in Conc-StoneCurb) and follow the pop-up prompts. The Name Prefix is CB-by default.
3. Click on the reference element for node elevation (active terrain or edge of road) or click reset to type a node elevation, type in 0.00 for vertical offset, this can be changed later for the gutter depression of Type "C" catch basins. Rotate as needed to place.
4. Hover over the node to enable the context toolbox: properties, utility properties and delete. The node can be moved and rotated.
5. Continue placing more structures (catch basins, end structures or manholes). After you placed the last structure, right click once more, and select the Element Selection tool to end the Place Node command.
» Place Culvert End (Node)
1. Select the Place Node command to place a culvert end.
2. Select the Feature Definition (example: 24" RCCE) and follow the pop-up prompts. The Name Prefix is RCCE- by default.
3. Click on the reference element for node elevation (active terrain or edge of road) or click reset to type a node elevation, type in 0.00 for vertical offset. Rotate as needed to place.
4. After the conduit is placed click and hover over the culvert end for the context menu, click on properties.
5. In the properties box, change the following:
- Use Slope of Surface = False
- Match Slope of Conduit = True
» Feature Definitions for Drainage Nodes
» Inlet Catalog
All inlet nodes (structures) available for design are stored in the Inlet Catalog.This catalog has been set-up for all catch basin types and other structures according to CTDOT standards.
To view the inlet catalog: Click the Components tab – Catalog – Inlet Catalog
PLACE CONDUIT
Conduits are placed between nodes such as catch basins, manholes and head- and end walls.
Note: If a structure is deleted the associated conduit connecting the node is also deleted.
1. Select the Place Conduit command, choose the Feature Definition for the pipe you want to place (example: RC Pipe). The Name Prefix is SW- (Storm Water) by default. The Type: is greyed out – this comes from the conduit catalog already attached, for Description click on the down arrow to select the pipe size (example: 15”).
2. Follow the prompts: Select Start Node, in the drawing hover your courser over/close to the first inlet (node i.e. catch basin), it will snap to the node where the conduit can connect, this is called the Connection Region. Accept (left click).
3. Select next node to make a connection. Again, hover your cursor close to the inlet to connect the conduit to (second node i.e. catch basin). Accept (left click).
4. Continue to place conduits to connect the drainage structures from the first inlet to the outlet for the system. Select the Element Selection tool to end the place conduit command.
» Conduit Catalog
Go to Components - Conduit Catalog to see available conduits. In the Conduit Catalog the designer is able to set conduits Available for Design for the drainage design.
INPUT INVERT ELEVATIONS
After completing the layout for the drainage structures and conduits you will enter the invert elevations for all structures and conduits, Drainage and Utilities sets conduit inverts to the bottom of the structures by default.
Drainage and Utilities has the capability to calculate the pipe inverts when you use the Base Design Scenario in the Hydraulic Analysis. The Default Design Constraints need to be set for the project as required. It is recommended the designer reviews the Bentley Learning path for Hydraulic Analysis and Design in OpenRoads Designer.
By selecting a placed utility feature, some feature properties can be edited, rotated and/or moved in the graphic (just as with other OpenRoads tools), it shows the label and level. Also, the context toolbox displays and offers two options to input/edit utility information:
Properties - lists the CADD properties such as level, color, feature, feature definition etc.; and
Utility Properties- lists every available hydraulic property including user customized properties.
Drainage and Utilities tools represent the merger of two diverse technologies. OpenRoads Designer builds the 3D models of the utilities, but Bentley's Haestad technology (StormCAD) executes the analytic modeling for hydraulic and utility engineering. We will concentrate on Utilities Properties.
» Utilities Properties
– Node
Click and hover over a node (catch basin or manhole) from the context toolbox select Utility Properties, click on the Hydraulic Analysis tab.
Check and edit the physical properties for the node:
- Elevation (Ground) = Terrain elevation at node
- Set Rim to Ground Elevation? False/True
- Elevation (Rim) = Top of Grate elevation
- Elevation (Invert) = bottom elevation of structure
- Update and edit Inlet properties for the node:
- Inlet Type: set to Catalog Inlet (CTDOT lnlet library is CV_SubsurfaceUtilities_Inlet.xml)
- Inlet: click the down arrow and select from the available structures
- Other items edit can be edited later
The Inlet catalog: CV_SubsurfaceUtilities_Inlet.xml has been set-up for CTDOT catch basin standards and will be updated as needed.The catalog should be available automatically when starting the drainage engine, but is also available here:
State of Connecticut\DOT CTDOT_DDE - CONNECT\CT_Configuration\Organization-Civil\_CT_Civil_Standards – Imperial\Data\CV_SubsurfaceUtilties_Inlet.xlm
– Conduit
Click and hover over a conduit, in the context toolbox select Utility Properties, click on the Hydraulic Analysis tab.
Check and edit as needed the Physical Properties for the conduit:
- Conduit Type: Catalog Conduit
- Catalog Class: click the down arrow and select: Concrete, PVC, CMP
- Size: click down arrow and select size
- Invert (Start): enter elevation
- Invert (Stop): enter elevation
- Has user Defined Length? True (default) or False
- Length (user defined) enter length
- Other items will be edited later
Most used conduit classes have been added to the catalog, if others are needed those can be added:
Click Catalog – Conduit Catalog – Import from Library
Select the conduit to add from the available Conduits Library.xml.
DEFINE DRAINAGE AREAS (Catchment Properties)
Drainage areas are defined using existing and proposed terrains, which can be merged with terrains coming from various other sources such as LIDAR.
there are several options to place catchment areas (see Bentley Help):
- Place Catchments by Picking Shapes
- Place Catchments by Picking Points
- Place Catchments by Flood Fill
Catchment properties include catchment area, runoff coefficient, time of concentration types, and time of concentration.
» Catchment Area
1. From the Layout Tools select Place Catchment and select the Method that best serves your purpose: example Pick Points
2. From the Feature Definition pick the land use most appropriate for the catchment area: example Pavement
For each land use prototypes have been created that follow the CTDOT Drainage Manual. The designer should adjust the Runoff Coefficient (Rational) for the project if needed in the Hydraulic Analysis tab for the catchment area.
3. Follow the command prompts: Select First Vertex, Select Next Vertex, (Reset) To Complete, Select Outflow, and Select Reference Surface.
» Runoff Coefficient
Runoff Coefficients have been defined as prototypes following the CTDOT Drainage Manual. They are composites from Chapter 6 – Runoff Coefficient – Table 6-4 Recommended Coefficient of Runoff Values for Various Selected Land Uses and Table 6-5 Coefficients for Composite Runoff Analysis. More Catchment types can be added and/or the coefficients can be changed specific to the project need.
» Time of Concentration
Time of Concentration (Tc) is defined as the time required for a particle of runoff to flow from the hydraulically most distant point to the outlet or design point (catch basin etc.). Factors affecting the Tc are length of flow, slope of flow path and roughness of flow path.
Please see the CTDOT Drainage Manual - Chapter 6 for more detail.
Tc Input Types:
User Defined Tc -where the user inputs minutes for Tc or
Composite Tc -where the user inputs a data collection of Tc’s (Tc Data Collection)
.
» Time of Concentration using Tc Data Collection
This follows the CTDOT Drainage Manual by using the TR-55 Sheet Flow, Shallow Concentrated Flow and Channel Flow Tc Data Collection method.
- SHEETFLOW
- SHALLOW FLOW
- CHANNEL FLOW
PLACING GUTTER STRUCTURE
Gutters are the method by which a catch basin bypass flow is assigned to a downhill catch basin (inlet). Gutters only represent the hydraulic relationship between the inlets and are not accurate 2D and 3D models.
To display and add gutters to a drainage system:
- Turn Off Annotation Scale Lock (it is usually turned on by default): Drawing Production tab – Drawing Scales tools – Annotation Scale Lock
- Change the display in the 2D view to use Analytic Symbology. In View 1, Default (2D view) click on View Attributes, check off ‘Text’ under Presentation, then expand the Analytic Symbology (if not expanded) and check on “Use Analytic Symbology”. This will turn on “labels” in the plan view (2D view only). If the labels do not show, refresh the view.
11.9.3 - Uniform Cross Slope Procedure and
11.9.3 - Full-Super Uniform Cross Slope Gutter
11.9.4 - Composite Gutter Sections Procedure and
11.9.5 - V-Type Gutter Sections Procedures.
The engineer (user) has to decide which gutter best fits their project and edit as needed.
2. From the Feature Definition select the Gutter needed for your project.
Example: Uniform Cross Slope Gutter for proposed, Uniform Cross Slope eGutter for existing.
3. Follow the prompts: Select Start Node.
4. Select next node to make connection. <Alt> to place curve. <Ctrl> to place bends. <Reset> to select start node. Example select the next node.
5. After placing the gutters turn off the analytic symbology under view attributes.
CREATING STORM DATA
Storm Data is a single rainfall curve that represents one rainfall event for a given recurrence interval. Once the storm data is created it can be used globally by selecting Global Storm Events.
1. Click on the Components tab and click on the Storm Data tool.
Several methods for specifying storm data are available, the User Defined IDF Table will be discussed and used.
2. Right-Click on User Defined IDF Table, New, User Defined IDF Table.
3. Right-Click to rename the new User Defined IDF Table; example IDF_Table_Prj_No_XXX_YYYY
There are two options for the precipitation frequency estimates to be imported or used: Importing an IDF Table from a File or Creating a New IDF Table using the Dialog.
» Create IDF-Table by importing CSV-file
- Use Excel to open the PF_Intensity_English_PDS.csv file saved from NOAA Atlas 14.
- You need to edit the file to only show the columns for durations and the rows for minutes.
- It is recommended to edit further by adding/interpolating the data for more minutes, follow Hydraulic and Drainage recommendations.
- To import an IDF table the data has to be in either the CSV-format or in a TXT-format.
4. In the Storm Data box select the user Defined IDF Table (IDF_Table_Prj_No_XXX_YYYY) and click on the Import icon.
A Warning message will come up (Importing data will clear all ….) click Yes.
5. In the Explorer select and open the NOAA Atlas 14 (edited & interpolated) CSV-file. Imported data will be populated in the Storm Data window.
6. Close the Storm Data box.
7. Select the Tools tab, click Options, Drainage – this will open the Options box.
8. In the Options box click on the Units tab. Scroll down to the Rainfall Intensity and ensure that it matches the units in the IDF file. Click OK.
» Create IDF-Table Adding Return Periods and Durations (quick & dirty)
Repeat steps 1 through 3 to create an IDF-Table. Instead of importing a CSV-file, we are adding data into the Storm Event Input.
- In the Storm Data box under the Storm Event Input tab, click on the down arrow for Add Range…
- Add the years needed for your project; example: 2 enter, 5 enter, and so on for: 10, 25, 50, 100 years.
- Click on the down arrow for Add Duration and Add Range… Enter the data from the saved PF_Intensity_English_PDS.csv file.
Start in the first column, enter the data, tab to the next column, and enter the data and so on.
