Modeling Arch section shapes in SewerGEMS

   
  Applies To 
   
  Product(s): Bentley SewerGEMS, Bentley CivilStorm, Bentley SewerCAD, Bentley StormCAD
  Version(s): 08.11.03.84
  Environment:  N/A
  Area:  Modeling
  Subarea: 

Problem

What are the current limitations and considerations with using the Arch and Pipe-Arch section shapes in SewerGEMS, CivilStorm, SewerCAD and StormCAD V8i SELECTseries 3?

After creating or importing one or more Pipe-Arch section sizes to the conduit catalog, if you try to select that conduit from the property grid, it is not available. The section type will not list the pipe arch item.

Solution

General

Currently, when using the Implicit solver in SewerGEMS or CivilStorm, the pipe arch shape (entered in the conduit catalog) is not supported, hence it's not listed in the property grid. If it is required to model then consider these options:

A) Set the conduit type to User defined and utilize the "Arch" type, which is a similar shape.

B) Use the Irregular Section shape.

C) If using SewerGEMS and if feasible, use the GVF Convex Solver, which does support the Pipe-Arch shape.

When using the GVF Convex solver in SewerGEMS, or when using SewerCAD, the opposite is the case. The "arch" shape, (entered as a user defined conduit) is not supported, whereas the Pipe-Arch shape (entered as a catalog conduit) is supported. 

Modeling Culverts

If you're modeling a culvert and want to use the "Is culvert?" option in the properties of the conduit, note that Arch and Pipe-arch are currently not supported conduit shapes. So, the "Is culvert?" field will not be visible/available in the properties of conduits with those shapes. The reason is because the numerical solver used for culvert calculations is shared with Bentley PondPack, which has historically only ever supported the Box and Circular shapes. So, the following workarounds should be considered in this case:

A) Simply accept that the HDS-5-based culvert calculations will not be used in this case. When using the Implicit dynamic solver, entrance losses will still be simulated.

B) If the roadway overtopping feature needs to be used, or you must use HDS-5-based culvert calculations, change the conduit to an equivalent box or circular shape.

Note that an Enhancement request (# 89068) has been logged for adding support for different section shapes with the "Is culvert?" option. This will be considered for future versions.

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