Culvert Design

[SteelPE]

I have a client who is asking me to design a concrete head wall and footing for a Contech aluminum culvert. I am a little surprised that there are no "typical details" for the design of the head wall. I understand the forces involved but what I do have questions about is whether or not the footing for the culvert needs to be founded below frost elevation.

We have asked Contech about this only to get mixed answers. They swayed us towards providing a footing below frost depth but did so reluctantly.... basically saying "if you think it should then we agree". The civil engineer is not giving much help either.

Should the footing for the culvert be placed below the frost elevation for the local jurisdiction? What do others do in this situation.

 

[dicksewerrat]

Call your local Hansen Concrete Pipe office and get their catalog. They probably make this item. Then call the local DOT office to ask about the frost footing issue.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[bridgebuster]

Besides frost, you also need to consider scour depth when setting your footing elevation.

 

[gbam]

SteelPE,
Have you checked with your State or local DOT. They may have standard details for headwalls. If not, check neighboring states or FHWA to see if they have standards. Have you called your local Precast Company, maybe they have a precast unit?

 

[civilman72]

As already stated, you may find that scour depth is what will drive your design depth. I would determine that before worrying about frost depth.

Also, anticipated frost depth is usually decreased when under or adjacent to water (assuming the creek/river does not completely freeze).

 

[beej67]

The civil should be able to calculate a scour depth. If not, and if you don't feel comfortable doing it, make sure someone does it and make sure you CYA yourself on it, because that's what's most likely to cause a failure.



Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[DwayneM]

Steel,
Are you planning to stamp this design? Seems to me "the civil engineer" should be able to give you some guidance on expected scour depth - or for that matter the maximum elevation of the bottom of the footing.

 

[SteelPE]

Right now we have a preliminary design out for pricing that places the BOF at frost depth. As suggested above, I have checked the state DOT website to see if they had any suggestions....... I never did find anything however, I did find a standard table for retaining walls that placed the BOF at frost depth.

When I was approached about the design I couldn't believe the Civil didn't have any typical details for this scenario. They have been kind of useless through the whole process. I am used to designing buildings and their foundations (which includes retaining walls). I have always thought that retaining walls were something that a structural or a Civil could take responsibility for.... I guess this Civil is not comfortable with that statement.

 

[beej67]

A lot of civils who's primary focus is generic land development (and not specifically bridge crossings) don't have the technical expertise in-house to do scour analysis. It's not that uncommon, because of the way the business model responsibilities break down. As I said, CYA yourself on scour, and if you don't feel comfortable doing it insist someone else does it, or insist someone else holds you harmless for nobody doing it.



Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com