profile pipe slopes slightly off

[idiggplants]

first post here. hope to get a lot figured out that i couldnt on the autodesk forums. seems like a less "official" environment around here. more relaxed.

 

ok, so 2 structures, one invert at 342, the other at 341.75

the pipe length is displayed as 43'. that is 3d inside to inside. the slope is displayed as .55%. the engineer running hydroflow says the slope should be .58% i tend to agree.

its like autocad is using the pipe slope based on center to center length, but hydraflow is using the slope based on inner wall to inner wall. is there a way to change the slope to read correctly?

[idiggplants]

also, thanks very much... gonna have a few questions that have been on my mind right off the bat. hopefully they are posted in the correct place.

[Tiger]

I must be confused, isn't the slop always the same? Center/center or Inner wall/inner wall - the pipe tilts the same, doesn't it?

[idiggplants]

well... it is assuming you are using the same inverts and distance. if i label the pipe distance based off of center to center, the math adds up. the pipes are also drawn center to center by civil3d. in real life tho, the invert labels the pipe at the inner wall of the structure. and the pipe legnth is also taken from inner wall to inner wall.

 

see pic.

 

the invert i assigned to the pipe is 333.75

the red arrow is at 333.64

the green arrow is at 333.75

 

in real life the magenta pipe would be where the pipe was placed with the given invert.

 

the yellow pipe is what is given.

 

the distance i have displayed on the pipe is measured from inside wall to inside wall.

the inverts displayed are based off of center to center.

ideally we want to use real world figures in hydraflow. so she uses inside wall to inside wall figures. and the inverts are inside wall to inside wall. so her % in her report are off compared to mine.

 

i can either figure out a way to draw it correctly(perfect world), or i can make our measurements shown on the plan inside to inside with a note, as we used to do. regardless. the way it is drawn on the plan is not the same as real life. which seems weird.

 

im not necessarily looking to fix the problem, im looking to see how other people address it.

 

thanks for your time. i do appreciate the help.

[Organic]

im not necessarily looking to fix the problem, im looking to see how other people address it.

 

thanks for your time. i do appreciate the help.

 

If I'd doing hydraulic design using a software package I use whatever the package uses (generally from the wall of pit 1 to the wall of pit 2). Although different software packages do it differently as you explained above. When I'm manually doing hydraulic pipe design with pen and paper I simply go from the theoretical centre of pit 1 to the theoretical centre of pit 2. For standard pits which are

 

Civil 3d has a lot of limitations and quirks about it