Settings Appropriate for the structure attached! (Sewer Cad)

It might help if you could describe this structure more and explain how the hydraulics work.

My Initial thoughts on this are rather than represent the structure as one element you might try to break it down into its parts and represent each element individually. For example, it looks like part of the structure has a weir at a level of 5.00 m I'm guessing. You might be able to represent this as a conduit with a start or stop control structure. I might try to represent the first and 3 parts of the structure as conduits too and represent the 4 and final part as a wet well. After you tell us more about the hydraulics of the structure with more details we may all have some different ideas.

Regards,

Mark

Mark,

This structure serves as a pressure breaker and part of the structure is a weir. If you will notice the invert of the incoming pipe was raised to elevation 9.7m (for the 4 pipes ref. at Section A) and elevation 4.78m (for the 2 pipes, ref. at Section B), this is to break/lessen the pressure. Then, these inflows are going to a weir and from weir it will go to the last part of the structure and it will pass through at 2 nos. of 900dia sluice gates and it will go to a wet well through a 900dia pipe.

I also want to add that this weir has there (3) levels, first level (bottom) was at elev. 3.0m then it will overflow to the next weir at elev. 4.0m, then it will overflow to the next weir at elevation 5.0. This is what they have inside. But since it is already existing and operating, I suspect that the weir is always full, so meaning whatever volume of water will come in, the outgoing volume of water is the same.

I hope the description I provided helps you on some ways to figure out what is this structure.

Thank you very much!

Best Regards,

June

June,

In this situation I would probably use the approach that I have outlined in my first reply, which should help to keep things simple for you. I'm not sure that I follow the way all the chambers are connected and how many pipes come into each, but if my understanding is correct it might look something like this. I apologize if I didn't get the exact setup of all the pipes correct, but this should give you a basic idea of what I am thinking.  

For pipes P-1 and P-2 if you wanted to have them at different elevations connected to the wet well then you could just set the property for the "Set Invert to Start?" or "Set Invert to Stop?" to 'False' then enter the elevation you want the pipe to enter or exit at. You can apply this method to other places where you may need to add more pipes too, in order to define their entrance or exit from the structure it connects to. As you can see in my example model above I choose to use transitions rather than manholes for the connections between the chambers because they will allow you to define transition length and really just convey flow from one pipe to another. If you think a manhole is more appropriate in your engineering judgment you can use that too or you can take advantage of the scenarios and alternatives feature we have and try both to see if there is a difference. I suspect that the difference would be small if there was one, but you understand the design of structure better than I do.

To model the weir I set conduit CO-2's property for "Has Start Control Structure?" to True and then created a weir control structure to model your weir. As you have indicated you may not need to do this since the structure is already operating and the weir is always full so you may just be able to model this as conduit that would give equivalent flow as that part of the structure.

To sum up the one piece of advice that I have is to not overcomplicate the layout of the structure if you don't have to.

I hope that helps out.

Mark

Some further thoughts on this:

It sounds like flow enters this structure on the right side via four pressure pipes connecting at elevations 9.7 m and and two pressure pipe at elevation 4.78 m. It looks like the weirs discharge into two smaller chambers on the left side, each of which connect to a separate wetwell. Does that sound accurate?

With Mark's approach, wetwell W-1 could represent the combined volume of the two smaller chambers on the left side of the drawing plus the two separate wetwells that they connect to. If you need to model the effects of the flow control between the chamber in the middle and the two smaller chambers on the left side, or if the two wetwells fill and drain independently, you could use a diversion rating table. If you don't need to account for any attenutation effects of the main structure and weirs, you could simply model it as the pressure pipes connecting to a conduit at their respective inverts (to ensure that the upstream pump adds enough head to lift the water to thos respective inverts, as discussed in another thread), with two conduits splitting off from there to the two wetwells. One of these could have a start control structure to model the restricting flow control (such as the sluice gate) and the other would be a diversion rating table.

If you had Bentley SewerGEMS, you could model the structure as a pond, with multiple outlet structures to represent the flow divide to the two separate wetwells

If you need further assistance, it may help if you can explain a bit more about what kind of answers or information you ultimately need to get from this model.