Water Tank floor & roof beam support

[ottles]

I'd like the water tank to be supported on the floor slab and also at the roof I-beam with each contributing half to the support capacity (the roof I-beam would have bars going down carrying half the tank load). How do I make sure the roof I-beam and floor slab has roughly equal load (or least neither having the full load).. any instrument to do that? or perhaps I can put the water tank on a weight scale permanently? How do you do it?

 

[MotorCity]

Can you post a sketch of how you propose to support it from the slab and roof deck? In order for the load to be shared 50/50, the stiffness of the floor and the roof needs to be the same. If you can demonstrate this, I think in theory it could work. The problem is that if your roof has any variable loading such as wind or snow, the deflection of the roof may result in the slab picking up more of the load. Also, I would be very careful about attaching structural members to a tank. Tank guys are a little fussy about that, and rightfully so as it could create a condition which the tank may not have been designed for. This arrangement is not conventional, I would suggest supporting the tank from the floor slab. If you hang or suspend it, you have in effect created a pendulum which opens many other cans of worms.

 

[JAE]

And to add to MotorCity's points - if the floor gets loaded up around the tank, then the floor will deflect downward, imposing more load on the roof.

Some kind of springs, top and bottom, could conceivably dampen the differences but I haven't thought through all that.

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[ottles]

Jae, when you mentioned "if the floor gets loaded up around the tank, then the floor will deflect downward, imposing more load on the roof.".. were you talking about the tank just standing on the floor or also connected to the roof? Because if it's just standing on the floor and the floor deflecting downward, why does it impose more load on the roof when it's not connected to the roof?

 

[KootK]

By floor slab do you mean a structural CIP slab or a thin concrete deck on steel beams? A sketch would be great.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[JAE]

ottles - yes - based on your concept of the tank supported by both the floor and roof - per MotorCity's point about the roof load dropping the roof a bit and loading up the slab - I was just pointing out the reverse, that if the floor is loaded up the deflection would send more load to the roof.

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[JStephen]

This tank is elevated some way, supported at the shell only? Then floor and roof both span across the diameter and you're proposing to tie them together to get some of the water load supported by the roof?

 

[ottles]

Thank you all for the pointers.

 

[JAE]

ottles - those last questions of yours are more in the mechanical engineering line of things so I'm not sure we structurals can answer them. We like static stuff...water moves.

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