Engineering Help for Steel Stand (320g)

[o2manyfish]

I need some "smart" help with my stand, please

All my filtration is outside. So I don’t need anything under the tank, excluding a pair of 2" pipes. So my hope is to build a stand which has a large empty opening under the tank, and has almost no support along the front. The stand will be tied into the house walls on the entire right and along the entire back. But on the front edge, I wanted the stand open and empty. Behind the curving facade, I can have additional support legs.
I am hoping someone has the engineering skills, or software to let me know how many cross pieces I need, How many legs, and most importantly what size support plate (yellow), and what size steel leg (red) to safely support the weight of the tank. I intend to make the stand out of 2x2 square tubing. The top of the stand will have 3/4� plywood over the steel bars, and 1/4� styro between the plywood and the tank. By my calculations with a beginning weight of 4000lbs, given the surface area of the stand the distribution is only 1.3lbs/sq inch.

http://www.o2manyfish.com/pics2post/stand_frt.jpg


http://www.o2manyfish.com/pics2post/stand_top.jpg

Thanks for the help.

Dave B

[o2manyfish]

Anyone with engineering skills ?

Please.

Dave B

[AnnArborBuck]

I would give you some help if I was a mechanical. I could design a distillation tower for you though. :)

[McMann]

Well i am by no means an engineer... although it was my major in college for a while. Although I do lots of work with metal and heavy weights so I can help you out some. First off I will ask if you have to have your leg recessed in like that?? I would just put it in the very corner with a 4x4x1/4" square tube. Like you said you are only looking at like 1.3 lb per sq/in so it isn't anything extreme at all for steel. I would just throw the 2x2's every 16 inches or so. I don't have any calc for it but I have build trailers that carry way more than 2 tons and they are out of aluminium and thinner walls.
I would really try to have that leg though again in the very corner. Otherwise you are talking 1300-1500 pounds in the midle of a steel plate and even with 3/8's plate that is still gonna bend some. Doesn't have to be a problem but you would need to know how much it is gonna bend so you can make sure AFTER the bend it levels the tank. So you would have to intentionally need to make the leg higher than the tank by a fer hundreths of an inch.
One problem I see though is what are you doing to reinforce the floor where this one leg is going?? Again you are looking at about 1400 lbs with a footprint of only 16 sq/in Can your floor handle the almost 100 psi?
I also think your 4000 pound estimate is extremely low if this is a ten foot long tank. Assuming 10x3x3 that is 90 cu/ft of water and 5500 lbs not including any rocks sand, or possible hood. I don't think any of this matters for the steel but it matters for the psi on that floor. If you can work that out the project is cake. 2x2x.25 (overkill but safety for spreaders and actually now that I look at it more you may want to use some small I beams for the front and rear pieces. On that front with the lopsided loads could cause a problem with dimension steel. I'll talk to my engineer friends tomorrow.
Biggest problem I see.,,, again how you are preparing for the psi of the leg.

[o2manyfish]

McMann,

The tank is only 8x3x2 -- And the 3 is the front to back depth.

The floor is a minim of 6" concrete slab on solid earth underneath. It survived the the earthquake in 94 with no cracks, and the previous tank only dropped one rock.

I really want the leg recessed so that is looks cool.

I could even seen making the leg like a 12+" Steel tube if that would help.

I definitely want to avoid building something where i have to guess what the flex is ?

Does this change any of your thoughts ?

Thank you for your experience.

Dave B


Does this change of any of your thoughts ?

[McMann]

OK talked with my friend and all today. As for my concern with the floor. With what you said it will be fine. I thought you were putting it over a conventional floor so you are more than fine there. After all my entire house is resting on a 4 inch tube on a three inch concrete floor.
Anyway that corner being offset just REALLY messes with the engineering of it. Obviously still doable just a little more difficult. Just make your ladder bar setup like you said and I would put the bars 14-16inches on center whatever works out nicely there. For that corner I would talk to whoever you are having weld it I would say 3/8 plate making sure you place it directly under one of the cross braces. You want the plate to sit on top of the tube and go out to a brace on both sides of it and to the front. Also having an X going from the tube to the plate corners. So the subit is pushing on the X which is pushing on the 4 corners of the braces. This is the only way we could see to still support that corner well. You could just make the X out of two small pieces of 1"x.5" bar stock. Both probably being 22 inches or so. Hope that makes sense. All this should make for a very solid frame and at most a couple thou deflection which isn't anything to worry about with the tank. The water will bow the glass more than that anyway. Again just tell your welder what you are doing and he may finetune it a bit better.
Matt

[cmagallon]

I'm back in Town If you need some Help! I sent you an email_Originally posted by o2manyfish
Anyone with engineering skills ?

Please.

Dave B