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How to convert a manhole into a bend in SewerCAD?

Using ModelBuilder, I imported shapefiles and created a sewer model. I am in the process of adding more data.  I realized that many sewer pipe bends and connections became manholes. I'd like to remove these false manholes and make it as a bend. Is there a simple way to do so?  I could re-create a new conduit and bend it, but I will lose all the information I imported for the conduits.  Please let me know if there are simple ways to work around this.  Thank you.

Yoko

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  • You could use the Batch Morph tool (Tools menu) to morph a selection set of these manholes into transitions, though you will need to enter the Top Elevation afterwards. You may want to take a look at your source shapefile. Each segment may be a separate line element instead of one continuous polyline. If it's not too late, it might be best to clean up the source file first.


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

    Answer Verified By: Yoko 

  • Thank you, Tom. Thank you, Jesse. Does it matter if the manholes are turned to a bend or a transition? How does it affect the model results?
  • SewerCAD (and StormCAD) calculates hydraulic grade on a pipe-by-pipe basis using gradually varied flow equations. It is solves as a network with a backwater or frontwater approach, so that the HGL from one pipe typically crosses continuously over to the next pipe, but not always. For example a discontinuity can be seen between two steep, supercritical pipes as explained in this article:

    Hydraulic grade discontinuity at steep pipes or across nodes (frontwater analysis)

    So, using a transition in your case could effect the results by way of having multiple conduit elements (which could also change the slope of the pipe), whereas using bends would mean you have one single conduit which is solved as one single conduit at a continuous slope.

    You may want to test the sensitivity using a sample area of your model (you might need to isolate it using active topology to make other elements inactive) - run the section of model with transitions, note the results, then convert to bends and compare the results. If you find that there is no notable difference, you could consider accepting the Transition morph workaround.

    If you deem that bends are the best approach and the conversion proves too tedious, I would encourage you to check your source data to see if it can be converted to continuous polylines (so that they can be imported as such, with the bends in the pipes imported as bends).


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

    Answer Verified By: Yoko 

  • Jesse,

    Thank you. Your answer helped me to decide whether to use bend or a transition. It turned out that many manholes created where service lines were connected with larger sewer pipes were not connected to the sewer pipes when ModelBuilder created the model. I could simply delete these 'floating' manholes.
    Thanks again.

    Yoko
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  • Jesse,

    Thank you. Your answer helped me to decide whether to use bend or a transition. It turned out that many manholes created where service lines were connected with larger sewer pipes were not connected to the sewer pipes when ModelBuilder created the model. I could simply delete these 'floating' manholes.
    Thanks again.

    Yoko
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