casing pipe design and spec 1

[pipe78]

I am working on a project which need do a steel casing pipe design (Carrier Pipe D=42", Soil Cover=17'). Where can I find some information to do calculate and spec for jack bore?

 

[RWF7437]

You can find spec's for steel pipe at AWWA.ORG and probably several other places. Do a web search.

good luck

 

[pipe78]

RWF7437, Thanks for your reply. I did as you said before I asked this question, but I couldn't find good information which I can use in NJ.

Have a nice weekend

 

[JedClampett]

I'm not sure you're going to find a real good reference. This kind of design is heavily influenced by experience in the area. I'd call some local firms that do this kind of work (I suspect there are probably just a couple) and ask them what they recommend. Also some municipalities have typical details for this kind of work.
We typically use 3/4 or 5/8 inch thick pipe for the casing. Don't forget that this pipe not only needs to support the earth above, but be able to withstand the forces of the jacking.

 

[pipe78]

JedClampett, Thanks a lot for your reply.

In this project, there is a higher soil cover. I use 60" dia. casing pipe and get norminal wall thickness is 0.9", so use wall thickness 3/4 inch and predicting ring deflection is about 1.15%. What do you think according to your experience?

 

[JedClampett]

That sounds about right. I'd use that as a minimum and require the contractor to verify that the thickness is adequate. The last project we used this technique we had a 30 inch diameter casing buried almost 30 ft. It was 1/2 inch thick.
Unfortunately, I'm not really an expert on this. I've utilized boring and jacking so I know a little about it.

 

[pipe78]

Thanks JedClampett.

 

[cvg]

don't forget that this casing will corrode. Unless you fill the annulus between the carrier pipe and casing with grout or sand, it needs to have adequate strength even with corrosion to support the earth cover. You may want to assume a design life of 50 or 75 years.

 

[pipe78]

cvg, thanks a lot to give me a good reminder.