leaking concrete watertank
leaking concrete watertank
(OP)
Hi,
I am facing a problem with a circular concrete watertank which is leaking (diameter around 10 meters and height around 20 meters).
Many longitudinal cracks are visible from the exterior.
No as built drawings for the stucture are available with the client.
The cracks measured looks between 0.4 and 0.6mm.
It will be a big mess to repair the cracks from inside and outside since there are really many and it will mean emptying the watertank for a long period of time.
The contractor is proposing, instead, to apply a PVC membrane in the interior instead of doing the repair works. The type of the membrane and its thickness are under study right now.
I would like to have your opinions.
On a side note, for water retaining structure equipped with a waterproofing membrane, what is the maximum allowable crack width ? 0.10mm without liner and 0.4mm if liner is provided ?
Thak you.
I am facing a problem with a circular concrete watertank which is leaking (diameter around 10 meters and height around 20 meters).
Many longitudinal cracks are visible from the exterior.
No as built drawings for the stucture are available with the client.
The cracks measured looks between 0.4 and 0.6mm.
It will be a big mess to repair the cracks from inside and outside since there are really many and it will mean emptying the watertank for a long period of time.
The contractor is proposing, instead, to apply a PVC membrane in the interior instead of doing the repair works. The type of the membrane and its thickness are under study right now.
I would like to have your opinions.
On a side note, for water retaining structure equipped with a waterproofing membrane, what is the maximum allowable crack width ? 0.10mm without liner and 0.4mm if liner is provided ?
Thak you.






RE: leaking concrete watertank
Dik
RE: leaking concrete watertank
Brian C Potter, PE
Simple Supports - Back at it again with the engineering blog.
RE: leaking concrete watertank
Looks like that they were doing some renovation works for the membrane and used a new one which was not successful.
RE: leaking concrete watertank
Here's a couple threads discussing possible solutions: Thread1, Thread2
Brian C Potter, PE
Simple Supports - Back at it again with the engineering blog.
RE: leaking concrete watertank
Well, as far as applying a PVC membrane, that is going to require emptying the tank for a considerable time. Plus with a liner, you need to provide details to seal any outlets, which is a nuisance and takes more time.
If emptying the tank is not an option or is just a pain, I'd use divers. The tank is not that large, it's probably a couple day job for two divers. They go in with dye wands, and if there's a leak, they can immediately follow with a hydrophilic injection material like SikaFix HH. The flowing water will draw in the injection material and it will swell up almost immediately. The diver can check with the dye wand if the leak is stopped. The results should be noticeable right away. You can have them wear video cameras and watch the whole thing, like a football game.
Note that any swelling material has a lifetime, but as long as it's not disturbed, you should get 10 to 15 years from it.
If the cracks were vertical, you could post tension the tank from the outside and shotcrete it. This would likely eliminate 90% to 95% of the problems. But I'd want the tank to be empty during post tensioning.
RE: leaking concrete watertank
Post tensioning isnt an option ! I will try with the divers thing !
regarding my question of limiting the crack width, is 0.4mm an acceptable crack width if the tank is equipped with a liner ?
RE: leaking concrete watertank
RE: leaking concrete watertank
RE: leaking concrete watertank
They should work the same, but if all else is equal, I'd prefer a membrane.
RE: leaking concrete watertank