Ice Pressure on Cantilever/Retaining walls

[arh13p]

I was out inspecting a 6' and 8' high concrete "tank" or "storage" facility. The dimensions of this structure is approx. 100' x 75'. The structure was designed with cantilever walls/footings and a reinforced concrete floor. The purpose of this structure is to store liquids/contaminated water. After this winter, I have noticed that there are cracks that have never been in the wall before and the owner of this tank thinks it is due to the ice pressure over the winter. This tank is outside and exposed to the weather elements. Has anyone ever had issues with retaining/cantilever walls cracking due to ice expansion? Should I design the walls for an addtional lateral load due to ice expansion. If so, does anyone know what that loading value that is? that lateral load would have to be analyzed as a uniform load across the entire height of the wall since I don't know at what location the level of liquids will be come winter. It could be 2 feet from the bottom or 1 foot from the top.

 

[ctbailey]

The US Army Corps has a cold weather research facility in Hanover, NH. They would know.

Craig

___
Craig T. Bailey, PE

http://www.bailey-associates.com

 

[kslee1000]

ctbailey is correct. USCOE has excellent information, including design manual for ice loading. It is required for all water retention structures in the cold region. For certain locations, the force due to expansion of ice could be quite severe. Also, I believe they offer free download for some of their publications.

 

[bimr]

You may have a situation with internal freeze thaw inside the concrete. The tank walls are probably saturated with moisture, the inside of the tank is liquid and the external tank is below freezing.

So you have an internal freezing scenario where the freeze front of the wall moves inward and outward with the weather and warming of the sun. The concrete is then subjected to freezing crystals with numerous cycles of freeze thaw in a condition with saturated concrete.

The solution is to keep the concrete dry with a liner of steel or plastic.

It is possible that the water inside may freeze and exert pressure trying to expand the walls. The preventative is floating wood beams or as an alternative; vertical blocks of Styrofoam affixed to the walls.

 

[arh13p]

Thanks,
Do you by any chance have a picture of the floating wood beams or styrfoam installed on a such a project? some of the walls I am working with are almost 20 years old. It makes sense that the water that has worked it way into the concrete is freezing and playing a role in the cracking of the wall. I am designing a new system this spring and we have discussed the option of installing ice compensators but this would be a first for me. I thought I would try to find some pictures so I know what they look like.