CRUSHING OF CAST IRON PIPE
CRUSHING OF CAST IRON PIPE
(OP)
This is a bit out of my area. I need to confirm that a buried 30 year old cast iron pipe is ok for resistance to crushing due to new construction work above.
Pressure stress, that's easy. My questions are ...
1. how to evaluate crushing stress ... should I assume zero assistance maintianing circularity from surrounding soil (seems a good approach)?
2.How to actually calculate a crushing stress if I can get hold of a (presumably) uniform vertical load (Roark ??)?
3. How should pressure and crushing stresses be combined ... Can I assume that due to the oval section shape that would result from crushing load, there will be an internal tensile stress in the wall that can be combined directly with pressure ?
Assistance greatly appreciated.
Pressure stress, that's easy. My questions are ...
1. how to evaluate crushing stress ... should I assume zero assistance maintianing circularity from surrounding soil (seems a good approach)?
2.How to actually calculate a crushing stress if I can get hold of a (presumably) uniform vertical load (Roark ??)?
3. How should pressure and crushing stresses be combined ... Can I assume that due to the oval section shape that would result from crushing load, there will be an internal tensile stress in the wall that can be combined directly with pressure ?
Assistance greatly appreciated.





RE: CRUSHING OF CAST IRON PIPE
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RE: CRUSHING OF CAST IRON PIPE
http://www.cispi.org/handbook/chapter5.pdf
http://www.cispi.org/handbook/chapter6.pdf
http://www.cispi.org/handbook/chapter7.pdf
RE: CRUSHING OF CAST IRON PIPE
Of course the actual thickness and iron strength, original and present bedding/support conditions, existing condition of the pipe (including joining systems), and future needs in all regards etc. are all factors that go into looking at existing pipelines in such fashions.
RE: CRUSHING OF CAST IRON PIPE
cast iron would be considered rigid and ductile iron would be flexible:
http://www.cispi.org/handbook/chapter6.pdf