Expressions for Pipe Deflection and Length

[Alan_Corey]

I am curious if anyone knows how to do this. I have an expression for a crest and sag curve that tells me the the elevation of a pipe at the PC and PT as well as the Curve Length but the curve length is given in odd numbers. See image below.

No contractor on this planet is going to install 5-20' sections of pipe deflecting each section 1 degree than cutting 13' of a 6th section in order to install 113 L.F., they would most likely either install 100 L.F or 120 L.F unless they absolutely could not make it work. So my question is; is there an expression for both the label style and pipe style that would round up to the nearest 20'? For example, I am using free circular curves to represent a crest or sag in this pipe network which I am prompted to provide a radius. If max deflection per 20 L.F of pipe is 1 degree then that is approximately a 1300' radius, which the system then creates a curve length based on those parameters, except I want it to create the curve length, then round it UP to the nearest 20'

[sirjoelsph]

Just to clarify a few things for my understanding - you are using a design profile to design the top of pipe elevation for what I assume is a water main?  Is the profile the final deliverable to your client or do you end up using that profile to create gravity or pressure pipes?  The more you could explain, the better we could help.

To start answering your questions - you can use an expression to "round" your value of 113 L.F. to either 100 or 120, depending which one you wanted.  You cannot use an expression to control the length of a pipe - but I don't see any pipes in your example anyway.  You would not be able to use an expression to control the length of the profile vertical curve in your picture either.

If my assumptions are right and that is a design profile with a vertical curve, you could look into creating profile design checks to control the length of your curves as you create them.  I'm not familiar enough with them to know if it will do specifically what you are looking for, but it's the only thing available to you in Civil 3D that I know of to get you close.

[BrianHailey]

In addition to what Joel said, why not just make the curve the correct length? You can set the curves to default to a specific length:

Or edit the curves after they have been created.

If you simply change the label so it rounds to the nearest 20', then when someone checks your design and subtracts the curve start station from the curve end station, they will notice a discrepancy.

[Alan_Corey]

You are correct, I am using a design profile to represent a watermain. Once I have the elevtion at the top of pipe then I copy the design profile and offset it by however many inches the pipe diameter will be. That will be the deliverable to the client. After a lot of experimentation, I have come to the conclusion that the best I could do is write an expression that would round the label to the nearest 20' but the length of the pipe would remain the same... this doesn't work for what I am doing because the length of the curve directly effects the next curve length down the line and before long I am trying to make up the difference using vertical bends, which I am trying to avoid. I then realized that when I use the free vertical curves, I am prompted to provide a radius OR a length so since I know the max deflection is 1 degree per length of pipe, I made the assumption that if the vertical bend is less than 1 degree then the length of the curve is 20', if the vertical bend is less than 2 but greater than or equal to 1 the length of the curve is 40' than 60' then 80' and so on. So far this has worked well and the curve length I am giving it typically provides a radius that exceeds the minimum of 1300'.