Cracking Concrete from Freezing Water in Corrugated Pipe

[Roguerider]

I am a structural engineer and have a situation where we have a corrugated plastic pipe formed inside of a square concrete column (pipe is 4" in diameter and column is 16x16). The top of the corrugated pipe is flush with the top of the concrete and open to the atmosphere. The bottom of the corrugated pipe is closed. Water is collecting in the pipes and freezing, and we are noticing cracks forming on the face of the concrete column. The reason for these cracks has been presented as being from the water freezing, expanding, and cracking the concrete. If the plastic pipe was smooth, of the same diameter over its length, and the top is open, I would say there is not expansion stresses on the concrete because the freezing water would not be constrained. However because of the presence of the corrugation, is this enough to cause constraint and create a plug that would cause the concrete to crack from the expansive forces of the water?

 

[Khashishi]

You should probably put this in the mechanical engineering forum. This is too real-world for physics . I'm not sure if a back of the envelope calculation will be sufficient, but you already have evidence that it has happened. You'd probably need a complicated finite element model.

 

[rbelli1]

Water freezes on top first so just about any geometry of pipe would cause cracking given enough length.

BoB

 

[Tom.G]

Water freezes on top first so just about any geometry of pipe would cause cracking given enough length.

And water expands 10% upon freezing. If it is frozen at the top it will expand sideways.

Can you pump it out and cap it?

 

[Roguerider]

Yes we could moving forward..We were just trying to explain why the cracking was happening. Thanks for the replies!

 

[Baluncore]

The corrugations are the problem, but only if the column / piston of ice is not confined at the top.

I had a similar smooth bore problem with a traveling boom irrigator. A boom support wire passed through guide/support plugs that rested in the top of vertical tubes. After a couple of years use, when it was moved on winter mornings, after being stopped overnight, the structure would suddenly collapse. It took a while to find the ice filling the tubes that had pushed the support plugs up to level with the top. Because the level of water in the tubes self regulated each time it froze and thawed, the ice never protruded much above the smooth walled tubes. The problem was quickly resolved with a drain hole drilled in the welded base of each support tube.

You might consider half filling the section of the hole with a full length of closed cell neoprene foam. If the foam could not float up and out it would provide a cushion to absorb the ice expansion volume. The addition of an antifreeze will not resolve the problem as it will be diluted over time due to cyclic overflow.