Steel Stand for 2.5 tonne aquarium

I am very VERY new around here. I am no engineer so I'll get straight to the point:
I need to build a STRONG steel stand for my 12-foot long marine aquarium. So fare I have gathered that I will need RHS of some sort. Maybe 50mm X 50mm X 5mm. I want the stand to be 1m high and 2.5-feet wide. The tank dimensions are 12' X 2.5' X 2.5'. I will but the steel in pieces and weld the joints together with the help of my friend. Are there any considerations I need to make? I would love a design or sketch of some sort to get this bad-boy rolling. I will be placing it in the living room. The floor is pretty solid.
Many thanks.


The picture below is what I am after. It was made using 70mm X 70mm X 4mm gal RHS steel for the frames and 50mm X 50mm X 5mm uprights:


http://i93.photobucket.com/albums/l4...0/DSCF1561.jpg

The steel stand looks pretty strong to me, but I'd be worried about your floor. 2.5 tonne is a fair load for such a small area. It would pay to consult with an engineer to see if there are any issues with this load on your floor.

Mick

As Mick says you need to be sure about the capacity at the location it will sit. You might need to underpin the bearers and joists with additional posts or even bolt more timber to supplement the bearers and or joists. That says professional advice. A concrete slab on the ground should be OK, but maybe not depending on design and build, a suspended slab would also need to have load ratings checked and confirmed (common ratings might be 650kg/m2, but can be less - so way under what you propose to place on it)

As to the structure - for a one off job even one that is a simple design like this is I suggest you take the measurements of the tank to a steel fabrication place or two and get some quotes based on the height you want the stand (as the other dimensions are set by the tank area).

This will need to be cut and welded together square and without any warping - an experienced amateur could do it, but for a one off that will go with you for a long time why take the risk. The fabrication guys will also know what strength is need for that load.

If I were building the stand you have shown in the pic I would be wanting a couple of braces so I would not be relying solely on the welded joints for resisting sway/ side forces. Adding triangulation to the design (on all sides) would allow smaller main members too. You would also need to extend some corner tags above the stand base so that the tank is held securely within the stand top area and can't be dislodged off the stand (at 2.5 tonnes that sounds unlikely, but I am aware of one similar that caused great damage when dislodged).

In summary - get one made. If you count your own time, that of your friend, the materials etc my guess is the cost will not be much different and you get the security of a professional design and build. Try your initial DYI skills on another project.