I am using StormCAD CONNECT Edition to model the storm sewer we are designing for a highway project. We have one scenario on the project where we are running a trunk line that is a 5' x 3' RCB under a roadway that has a curb inlet on it capturing water in the sump. There is a 24" pipe coming out of this inlet and we are interested in connecting the water from the pipe to the water from the trunk line. However, we do not want to use a junction box to make the connection since they will be able to just stub the 24" pipe into the side of the RCB. How would I lay out the model in StormCAD to account for such a situation without the use of a manhole/junction box node?
In StormCAD you can model the 5' x 3' RCB, as a concrete box conduit connecting to the catch basins, as you mentioned it has a curb inlet on it capturing water.
For the connection part of box and circular pipe, do you mean that you don't want any structure at the connection point of 24" pipe and 5' x 3' RCB trunk line? In that case you can use transition node in StormCAD which will be connection point between these two conduits. Layout >Transition element, or when you select conduit to layout, right click in drawing area and select transition as the connection node.
If this does not then please elaborate your query.
Bentley Technical Suppport
That is correct. At the connection, we have some reservations about using a structure node because there won't actually be a structure placed there. Instead we will just be stubbing the pipe through the wall of the RCB. The concern with placing a structure there is the fear of introducing structure losses into the calculation in a spot where there actually won't be any structure losses at all.
But really that gets at the larger question that I am curious about in this situation. I only have so much knowledge as to realistically what losses will be encountered in any given situation so I am still new at determining when a model in StormCAD starts to get away from calculating what is realistically happening hydraulically in a certain situation.
So really my question is, what loss method of the ones available should I be using on calculations for my nodes that are manholes and junction boxes joining two different pipes together and what loss method should I specify for my transition nodes that are representing pipes being stubbed into the sides of RCB's?
If you just want to see the losses through the transition one option would be to use the HEC-22 Minor Loss headloss method. This link has more information on this.
You can find additional information on the different available headloss methods by looking in the Help documentation. The Help topic "Junction Headloss Methods" would be a good place to start. Details on the HEC-22 Headloss Methods available for mainholes and transitions can be found the respective manuals.
Thanks Scott for the reply. After digging through the menus and help topics I have started to gain a better understanding of what is going on. I have one more question, what is the difference between setting a calculation to run in Energy Grade mode as opposed to Hydraulic Grade mode? The help topics didn't really shed much light on that.
This link has more information on that: What is the difference between Hydraulic Grade and Energy Grade "Structure Loss" Calculation Option.
If you use the HEC-22 Third Edition headloss method, you will need to use the Energy Grade method.