Steel stand construction?

In summary, Dave is struggling to build a stand for a large aquarium that will support the weight evenly and without distortion. He is looking for advice on how to tackle this problem. Anybody with experience in this area could help him out.
  • #1
KnowNothingMan
1
0
I am having trouble figuring out how "heavy" to build a stand for a large aquarium. I have tried calculating "moments of inertia" and "section modulus" values, but frankly find myself lacking in the ability to work out my problem, this is quite frustrating for me. :grumpy: I like to think of myself as reasonably inteligent, but I just can't work myself through this one. Perhaps soemone or "someones" can help me here.

Here is some info about the problem...

The tank (I guess it would be reffered to as the "load") has a flat bottom measuring 96" x 48".

It weighs, fully loaded, about 5000 lbs.

The weight will be pretty evenly spread across the whole surface.

It must be supported pretty evenly across it's entire bottom surface.

I have available to me (for free) rectangular steel tubing measuring 2" x 3" with a .089" wall thickness.

I want to leave as much open space below the load as possible. Ideally, there would be legs around the periffery of the stand, a top frame with cross members, and a matching bottom frame, with completely open space under the load. I would like to have the "ends" of the stand open, and have three openings along both the "front" and "back" sides of the stand. I was thinking the top frame would consist of an outer "frame" and eight equally spaced cross members traversing the short axis of the stand, on top of this frame I would have a sheet of 1" plywood to spread the load between the rails and and spread out the forces inflicted on the glass it supports.

This top frame is the first problem I was trying to tackle, how do I determine how much (if any) deflection there will be in the top frame assuming the legs are sufficient to support the load? I want to eliminate (or at least minimize) and kind of distortion in the top frame as this could lead to failure of the tank's bottom, a very unwelcome occurance as you might imagine.

Anybody care to take a crack at this? :confused:

Input would be greatly apreciated,
-Dave
 
Engineering news on Phys.org
  • #2
Some fairly random thoughts:

First off, what can you compare this with? You have got something a bit smaller than a compact car and about three times the mass. If you look at typical devices to support a car (jacks, axle stands, wheel ramps) you will soon see that you don't need much steelwork to actually support the load. For example your 2 by 3 tube has an perimeter of 10 inches and an area of 0.89 inches. If you balanced the whole 5000 lb tank on just one leg (!) that would only give an axial stress of about 2.5 tsi which is zilch for steel. The limiting factor of the design is likely to be the joints in the stand (bolted? welded? whatever?) rather than the steelwork in between them.

So your the main problem is making something stiff enough, and distributing the load evenly. The obvious way to get stiffness is to have some big triangles in the frame structure.

If I was designing this I would try to get some information from the people who make tanks as to what the base of the tank needs to stand on. It could be a thin piece of glass that needs to be on a flat surface, or for safety it could be thick enough to distribute the weight itself, so it only needs to be in a "frame" round the edges. Also , look at some commercial designs and see how their structures work to carry the load.

If your base (plywood) is very flexible, the load will be concentrated round the edges and cross members anyway. If it's very stiff, the load could also be concentrated at a few points if it's not flat enough compared with the base of the tank. You might be better off with a frame with an appropriate number of cross beams (back to what the tank makers recommend, again) and some soft material on top of the steel to cushion the glass against breaking.

Another issue is getting the load from the legs of the frame into the floor. Depending what the floor is made of or covered with, there may be a limit on a concentrated load. You don't want a leg of the stand to punch a hole through one wooden floorboard, for example. You may need a "frame" at the bottom of the stand, so the load is guaranteed to be spread over the joists in a wood floor.

Is the floor level or will you need to include some leveling devices in the legs?

You might want to think about portability. For example two 48x48 frames standing next to each other would be easier to transport than one 48x96 structure.

Sorry, no equations and ony one calc in the above - but thinking first and calculating later is usually a good idea when designing something.
 
Last edited:
  • #3


First of all, it's great that you are putting so much thought and effort into ensuring the safety and stability of your aquarium stand. It's important to have a strong and sturdy stand to support such a heavy load.

As for the construction of the stand, there are a few things to consider. First, the type of steel tubing you have available (2" x 3" with a .089" wall thickness) may not be strong enough to support the weight of the tank and its contents. It's important to use steel tubing with a higher strength and thicker wall thickness to ensure the stand can handle the load without bending or buckling.

Secondly, the design of your top frame with the plywood sheet on top may not be the most effective way to distribute the weight evenly and minimize deflection. You may want to consider using a solid piece of steel or a steel plate on top instead of the plywood. This will provide more even support and reduce the risk of any distortion in the frame.

In terms of determining the amount of deflection in the top frame, there are various online calculators and formulas available that can help you determine this. However, it may be best to consult with a structural engineer or someone with experience in building steel structures to ensure the calculations are accurate and the stand is strong enough to support the load.

Overall, it's important to err on the side of caution when building a stand for such a heavy load. It's better to have a slightly overbuilt stand than one that is not strong enough and could potentially fail. I would recommend seeking the advice of a professional and possibly using stronger and thicker steel tubing for the construction of your stand. Good luck with your project!
 

1. What materials are typically used for steel stand construction?

The most common materials used for steel stand construction are steel beams, columns, and plates. These are usually made from carbon steel, which is known for its strength and durability.

2. What are the advantages of using steel for stand construction?

Steel is a strong and durable material that can withstand heavy loads and harsh weather conditions. It is also fire-resistant, making it a safe choice for construction. Additionally, steel is versatile and can be easily customized to fit different design requirements.

3. How does steel stand construction compare to other types of construction?

Compared to other types of construction, steel stands offer a number of advantages. They are faster to construct, more cost-effective, and have a longer lifespan. Steel stands also require less maintenance and can be easily modified or expanded in the future.

4. What factors should be considered when designing a steel stand?

When designing a steel stand, it is important to consider factors such as the type of load it will be supporting, the height and size of the stand, and the location and environmental conditions. Additionally, the design should adhere to building codes and safety regulations.

5. Can steel stands be disassembled and moved to another location?

Yes, steel stands can be disassembled and moved to another location if necessary. This is one of the advantages of using steel for construction, as it allows for flexibility and adaptability. However, it is important to consult a structural engineer and follow proper procedures when disassembling and relocating a steel stand.

Similar threads

Replies
50
Views
3K
Replies
22
Views
2K
  • DIY Projects
Replies
5
Views
2K
  • Mechanical Engineering
Replies
11
Views
2K
  • General Engineering
Replies
7
Views
2K
  • General Engineering
Replies
2
Views
2K
  • General Engineering
Replies
3
Views
1K
  • General Engineering
Replies
3
Views
1K
  • General Engineering
Replies
1
Views
6K
Replies
4
Views
2K
Back
Top