How to pour grout under shimmed large tank area steel tank? 2

[Amr Abdelhalim]

There is a steel shimmed circular tank of diameter 6.0 m which needs grout to be poured beneath its base plate.

What is the proper way to apply grout under this area rather than just pouring using a circular formwork to ensure that the grout really sealed all the voids beneath the tank base plate, will using a grout pump makes any difference than the normal manual pouring method?

 

[LittleInch]

3m hose into the centre....

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Also: If you get a response it's polite to respond to it.

 

[JStephen]

First consider if you really need to fill the voids. Minor voids will just be accommodated by deflection in the bottom.
The hose-in-the-center method (or at various points around the bottom for larger tanks) has been used, but you can actually raise the bottom that way, too.

 

[BridgeSmith]

Is the tank already in place, or will it be placed after grouting?

Rod Smith, P.E., The artist formerly known as HotRod10

 

[MJCronin]

Amir ...

Many tanks of this size have asphault impregnated board beneath the tank bottom instead of grout.

https://www.eng-tips.com/viewthread.cfm?qid=406577

https://www.eng-tips.com/viewthread.cfm?qid=359944

MJCronin
Sr. Process Engineer

 

[BigH]

If the tank is already in place - besides the hose idea which might be hard getting in under the tank, you can put formwork around the tank base and then with a number of "bird mouths" ensure that the grout level in the bird mouth is higher than the base plate - this will force the grout under the tank. Else, through a similar system you can connect a small pump and force the grout under pressure - but make sure that the tank doesn't "heave".

 

[Amr Abdelhalim]

The tank will be placed on shims and then grout will be poured. A previous scenario on another tank, its bottom was corroded due to the improper way of filling voids with grout, this is why we need to eliminate this issue from happening again.

Also if I used a pump or a hose, how can I ensure that the tank bottom base does not heave?

 

[LittleInch]

Low pressure, low viscosity and most importantly measure the inside surface of the floor to within mm and stop if there is any deflection and pull the hose out a bit more.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BridgeSmith]

Also if I used a pump or a hose, how can I ensure that the tank bottom base does not heave?

Fill the tank with water before pressure grouting.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[LittleInch]

Filling with water though will just deflect the floor, but then you won't have any space left to grout!

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BridgeSmith]

It depends on the pressure that the grout is injected and how deep the water is in the tank, so maybe not fill it up, just make it deep enough to counteract the pressure of the grout.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[HTURKAK]

Amr Abdelhalim , this is not the way for the tank founding and erection.. 6m. dia . implies a concrete slab found.

IMO, the best practice is, provide asphalt layer (40-50 mm) and mastic asphalt or bitumen impregnated board under the annular plate/shell ..You may seal then if necessary or provide drip ring to prevent ingress of water..

You cannot pressure grout the space btw. tank bottom plate and found.