Problems with HY8 - Opem Bottom Arch Culverts

[Msullics]

Hi There,
I am relatively new to modelling with HY8. I am trying to model an open bottom arch culvert. When I switch to a round culvert or box culvert the program appears to work fine, but I get strange results with the arch option. Can anyone help?
Thanks,
..Mike

 

[Ryb01]

Mike,

If you could provide details on what issues you are having, the users of this forum have a vast knowledge base and would be able to point you in the right direction.

 

[Msullics]

I am trying to confirm the size of an open bottom arch CSP. I have no problem sizing a typical round CSP culvert or an embedded culvert but when I swith to an open bottom arch, the profile view has elevations that are way off the scale and I have no idea how the program is coming up with elevations that high. I have selected an arch from the list of available sizes.
Input data includes:
Min flow rate = 0.5 m3/s
Design Flow Rate = 3.9 m3/s (100 yr)
Max Flow rate = 4.0 m3/s
Constant road crest elevation = 3.0 m
Tailwater channel invert = 0.0 m
Culvert data
Upstream invert = 0.64 m
Downstream invert = 0.0 m
Culvert length = 16 m
Arch size selected - Approx 2740 mm x 1440 mm.

The profile shows an inverted road profile with elevations in the hundreds of meters?

Any suggestions?
Thanks

 

[Ryb01]

Msullics,

Not sure if it's a glitch in your HY-8 or not but....try addinng a constant elevatio of say 100.0m to each of your elevations and see what happens. Based on your information provided the profile should look something like this.

 

[Msullics]

Hi There,
I am still having problems with the side view. I have uninstalled HY-8, version 7.2 and re-installed it thinking maybe there was a problem installing it to begin with. I have attached the output file from Hy8 for your reference. You can see the side view has issues. I have reset the elevations as you have recommended but the problem still persists. On the side view you can see the elevations are in the 500 m range which is really strange. Also on the front view I have -450 m stationing which is also strange?

Any further suggestions?
Thanks,
..Mike

 

[dicksewerrat]

Look at the barrel sizing on I think page 7 of yuour report. The barrel span and rise should be your arch pipe size.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[Msullics]

Hi Richard,

I had selected one of the standard arches listed in the selection dropdown menu, The program generated the barrel sizing that you refer to in your response above. I realize the barrel span and rise should be the arch selected but apparently for some reason the program is not happy?
Thanks,
..Mike