Why would a culvert be replaced due to severe erosion at outlet?
Why would a culvert be replaced due to severe erosion at outlet?
(OP)
A city has asked me to design a culvert to replace one that they say is in "bad shape". I look at the culvert and it is a cm arch culvert with concrete walls for footings and a concrete bottom. Its diameter is equivalent to 8' and is under a busy road, in a flowing stream. The problem seems to be, not the pipe, but severe erosion at the outlet. The stream has undermined the wing walls and there is a fall of about 4' from the pipe to the stream. There seems to be a better solution of fixing the outlet situation instead of replacing the culvert. Am I missing something? I don't want to tell the city that we can just fix the outlet situation and they tell me why it would need replacing, thus I look like the idiot!





RE: Why would a culvert be replaced due to severe erosion at outlet?
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Why would a culvert be replaced due to severe erosion at outlet?
Does the person who is asking you to repalce the culvert have a technical background? Or is it somebody who may not know that only the erosion needs to be addressed?
I've found that many times, particularly in smaller cities with no true public works department, decision-makers know something needs to be fixed, but not exactly what...so they assume what needs to be done and request that. It may be beneficial to sit down with your client and let them know your perspective and see how it compares to theirs.
RE: Why would a culvert be replaced due to severe erosion at outlet?
RE: Why would a culvert be replaced due to severe erosion at outlet?
RE: Why would a culvert be replaced due to severe erosion at outlet?
RE: Why would a culvert be replaced due to severe erosion at outlet?
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Why would a culvert be replaced due to severe erosion at outlet?
RE: Why would a culvert be replaced due to severe erosion at outlet?
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Why would a culvert be replaced due to severe erosion at outlet?
RE: Why would a culvert be replaced due to severe erosion at outlet?
RE: Why would a culvert be replaced due to severe erosion at outlet?
Do you have information on the growth rate of your scour hole?
If the hole has stabilized, then it is currently about the correct size to dissipate the energy of the flow. It may be possible to leave the depression, reinforce with riprap or other broken stone, and dissipate the energy that way.
Or, you can put energy dissipators inside the pipe to slow the water before it exits.
You should read Chapter VI of HDS no.5 "Hydraulic Design of Highway Culverts"
RE: Why would a culvert be replaced due to severe erosion at outlet?
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