Help with calculating weight that steel tubing can handle

[King_Triton]

Hello everyone...

Would firstly like to say that i'm new to this forum so please forgive me if i posted this in the wrong place.

I am currently busy with a marine tank build and need some help as the title says.

I have 2mm thick 2"x2" steel square tubing which i am thinking of using for the stand. I just need help to find out if this steel will be strong enough to hold the weight of the tank. when filled the tank should weigh more or less around 1600kg.

The stand dimensions is : L = 1500mm, W = 1000mm, H = 1000mm ( sorry for metrics.. I'm from SA)

I have attached a pic of the stand so you guys can see where it will be braced as well. The bottom part of the stand will be for a sump tank, which will weigh a lot less as it will be shallow hold a lot less water.

Thanks in advance for the help

P.S. I have tried the online calculators and its all greek for me as I am not in the engineering field.. hence my search for help here...

[King_Triton]

Bump.. any help out there please.......

[Cake of Doom]

I will have a better look in a bit for you but just for a quickie; you'll need to brace the sides and back as well or risk it being quite unstable.

I'll check back in a tick.

[Kelly_Bramble]

Additionally, the loading configuration and support of the tank structure needs to be defined before calculations can start.

Be aware that this is not a simple task and time and effort is at a premium for most engineers.

[King_Triton]

awesome thank you so much. really appreciate the help. Ill wait for your feedback before redesigning with bracing..

[King_Triton]

Additionally, the loading configuration and support of the tank structure needs to be defined before calculations can start.

Be aware that this is not a simple task and time and effort is at a premium for most engineers.

Yes thank you. well if i understand your statment properly, the tank base will be a double base. but the weight i gave you will be the entire tank once filled up with water and rocks and livestock. hope this helps.

[JAlberts]

I have done some rough calculations and have some design suggestions for added strength and structural rigidity; but first, I would like to know if you can get the 2X2 tubing with a bit thicker wall. If so, this would improve the strength at the welded joints of the tubing.

[King_Triton]

I have done some rough calculations and have some design suggestions for added strength and structural rigidity; but first, I would like to know if you can get the 2X2 tubing with a bit thicker wall. If so, this would improve the strength at the welded joints of the tubing.

Hi there, I would firslty like to thank you for taking the time to look into this. I already have this tubing for building this stand, so was not looking at getting more steel, wanted to make do with what i have. but if push comes to shove then I would look at getting thicker tubing. The other alternative would be to get rectangle tubing for the upper outter frame of the stand. maybe something like 2"x1" tubing.. with 2.5mm or 3mm thick walls, as its cheaper than thicker walled square tubing for some reason.

[jboggs]

Careful there Jalberts. You don't know anything about the size, shape, or support points of the tank this frame is supporting. So you don't know where the loading points are. You also don't know the application. Is it stationary or moving? (Lateral and shock loading.) You also don't know how this frame is supported, and where. You don't know what factor of safety will be required. The OP mentioned that the tank could contain "water and rocks and livestock". Livestock? Really? Wouldn't the factor of safety for a tank containing rocks be different from that for a tank containing livestock? Shifting loads, etc. What failure modes are you considering (bending, buckling, "parallelogramming")? Is there any external support? What about the potential for human injury if the frame fails? These are some of the assumptions one must make to adequately design this frame, and unless the OP can tell you for sure about these you can only guess.

I'm not saying it can't be done with the materials available, but I am skeptical. That's a very heavy load for that steel. I'm just saying that a lot more information is required to complete a safe design. And its probably more information than can reasonably be shared within the confines of an online forum. Maybe others disagree, but that's my gut feel.

[JAlberts]

King-Triton, I completely agree with all of the above concerns expressed by jboggs so I believe you need to answer those concerns with a clearer and more complete description covering the application of your tank. Just for furhter clarification of one item in your description that is confusing to me and I suspect other forum members viewing this thread is the term "livestock" that you state will be in the tank. Can you also be more specific in this regard as well?

As to the issue of your suggested 1X2 tubing, this would be a step in the wrong direction and I would definitely not recommend this material for the frame. I appreciate your desire to minimize your cost but, as stated above, the tank loading is very high and having an adequate structure for its support is much more important than the cost of the materials needed to achieve a positively safe support structure.

jboggs, I respect and appreciate your comments. I have previously attempted to post some basic significant design revisions to the structure that will substantially increase its loading capacity and address the stability issues that concren you. Unfortunately,at this point that posting is still residing in a black hole somewhere in the system. If it does not emerge this morning I will attempt to repost it for your review.

[JAlberts]

As stated above, yesterday I attempted to post some suggestions addressing strength and rigidity issues with the supporting frame shown in the thumbnail image in the original inquiry post but my posting seems to have gotten lost in the ethernet, so below is a copy of the text in that original post.

I first want caution you that my following recommendations are not based on actual stress calculations on all of the tank support members and therefore this cannot be considered a total engineered design for the stand. They are simply the minimum elements that I recommend for such a structure as you are building. I would also recommend you carefully consider the inputs of other forum members as well, both as comments to my recommendations and alternative recommendations of their own.

Based upon your load and the tubing description the actual column loading stress on the tank stand legs is very low but, as stated above, the stability of the stand absolutely requires cross bracing on all four sides. My recommendation for this bracing is that on each long side you run two braces in a "V" shape from the center of the top1500mm side members to each of the bottom corners of the stand and on each end of the stand use the same arrangement. By using the "V" arrangement you will provide both the stabilizing required and provide additional load carrying capability to the center of the top horizontal beams.
I would also recommend that on the top corners of the frame you place gusset plates between the each horizonal tube and each leg tube of the stand to help transfer the loading from the top tubing to each stand leg.
One other recommendation I have is on the 1500 mm long top tubes of the of the stand is to place one center horizontal cross brace and two or more braces equally spaced between this center brace and ends of the of the stand from from one side tube to the other to support the bottom surface of the tank and this is absolutely mandatory if the tank you are using is designed to normally sit on a flat horizontal surface; also, you may want to do the same on the bottom of the frame to help support the sump tank bottom.
I apologize for not sending a diagram showing my arrangements but time availability is an issue there; however, if there is any confusion on what I am suggesting please revise your diagram as you understand my instructions and I will be glad to review it and hopefully clarify any misunderstandings.

[RWOLFEJR]

Sounds like a fish tank to me... Water... rocks... livestock. Only livestock I know of that lives in water... fish. Well maybe a gator or turtle tank too? Or something that likes to sit on a rock near water.
But could be mounted on a truck bed too I suppose.

I didn't read through all the answers entirely so excuse me if I'm repeating things. Saw concerns on use and applied loads etc. and mention of gussets. Gussets are a huge help and if you're concerned about looks or blocking the view etc. you could whip up some very unobtrusive gussets that would still add a lot of strength to your base. You could get as fancy as you want if you have access to the right equipment? Curly and swirly or maybe company name and logo? Maybe spider web gussets? Something burned into a plate gusset that goes with the theme of your tank?

[Coigula]

"Please aware that this is not a simple task and time and effort is at a premium for most engineers."

Common sense is at a premium it seems too. The engineers decided that a this a terrapin tank on a traveling road show traversing gravel filled road 365 days a year. Kinda pompous and sell important statement typical of field and encouraged by employers but no solution was given.

I have seen 2" square tubing angle cut top and bottom at 10 feet long. Top frame needs to have cross bars every 2 square feet. This was in operation without angle bracing and worked fine for 10+ years. Coating steel is the hard part. and steel should be coated with marine paint or perhaps truck bed liner. No corner bracing was used, but less than 30" tall, and leg supports every 3-4 feet. Tank was run in reef crest mode as well holding stony corals and aggressive fish

That will be 5K please.