Steel Stand Integrity of My Design?

[Madreef]

Your stand isn't built for the load pushing down on it ideally. I mean that you should have one complete rectangle with 45s at the corners and then legs that connect the two, sorry I don't have any photos to illustrate this for you, but hopefully you understand what I mean. Your additional metal will do little if anything for support and will just add to weight and access to below the tank. I am not an engineer, but I do a fair about of welding and am in the HVACR business and have learned a fair amount about structural steel over the years on job sites. Your floor should be fine as long as it is level and was built in the last 40 years or so.

Even though I dont feel the stand design is ideal, I would bet that it will work just fine as is. The stands that I see most of the time can support 2+ times the weight necessary for the tank that sits on them. Once you fill it up it won't be going anywhere.

 

[Young Frankenstein]

Frankenstein, I picked up a 1/4" masonry bit on way home...Did two quick samples in the whereabouts where the stand will be and they are between 4-4.5" and took ~50-55 seconds to drill with a new bit and my Dewault hammer drill

Now you all think I'll be fine? Do you realize how much I've been stressing about this? I've sent specs on everything I have with weights, concrete slab depth, and models to two engineers and an architect!

Dont stress anymore, you are good to go. Lets see some fish swimin inthat tank : you have allot of work ahead of you

 

[Dustin1300]

Your stand isn't built for the load pushing down on it ideally. I mean that you should have one complete rectangle with 45s at the corners and then legs that connect the two, sorry I don't have any photos to illustrate this for you, but hopefully you understand what I mean. Your additional metal will do little if anything for support and will just add to weight and access to below the tank. I am not an engineer, but I do a fair about of welding and am in the HVACR business and have learned a fair amount about structural steel over the years on job sites. Your floor should be fine as long as it is level and was built in the last 40 years or so.

Even though I dont feel the stand design is ideal, I would bet that it will work just fine as is. The stands that I see most of the time can support 2+ times the weight necessary for the tank that sits on them. Once you fill it up it won't be going anywhere.

Not sure I follow. Which model of the two are you referencing? Did you read the whole original post?

 

[Dustin1300]

Dont stress anymore, you are good to go. Lets see some fish swimin inthat tank : you have allot of work ahead of you

I know I have a lot of work to do We are doing some remodeling work in the basement before I get the system going fully so my target is to have basement finished and tank with water, rock, and lights going.

 

[ironworker]

i am obviously an iron worker. i deal with this all day long, i can tell you if anything you may have over built this stand, not a bad thing.as long as your welds are good you could sit a mack truck on that tube steel. 1\4 inch is heavy tube steel i build machinery on it that sit in general motors plants. most people drastically underestimate the strength of steel. you do need to be sure your floor can handle it though.

 

[bct15]

Alright material discussion, my specialty. I can run through some basics on the steel stand.

The modulus if elasticity for steel (E) is 30000ksi.

2x2 1/4 in steel square will have a surface area of 1.75 in^2. You have a total of six, 6*1.75 = 10.5 in^2.

Assuming a weight of 8.7 lbf for your water, and then adding in three times the gallonage for your rocks, sand etc then multiplying the total weight by 1.3 (for safety) ^we get

1.3(600*8.7lbf + 3*600lbf) = 9126lbf.

Now dividing the total load by the surface are gives us the pressure (stress) on each support.

9126lbf/10.5in^2 ~= 870 psi

The formula relating strain to stress
E*e = S
Where e is strain, and S is stress

Solving for the strain on your columns ^we get

870 psi/ 30000000psi = 0.00002897 in/in

With way less then 1% strain (deflection) you are good there.

Now because the 6 supports can be considers columns you need to check for buckling...the formula for critical buckling load is
F=pi^2*E*I/(K*L)^2

Where K is 0.5 for fixed ends, L is the length of the column, and I is the moment of inertia

Applying this formula for three different columns at 12,24,and 36 in length respectively you get the critical load of
7496444 lbf, 1874111lbf, and 832938lbf. You should not have to worry about buckling.

In conclusion, stand is fine the way it is...I don't know much about concrete though so can not help there.

Though the calculations I listed indicate the stand will not fail, if it does...I take no responsibility. However, i highly doubt it will.

 

[Madreef]

Not sure I follow. Which model of the two are you referencing? Did you read the whole original post?

I'm referring to designing it different completely with less stuff in the way while still dealing with holding the load. Its just the way I see a solution for building a "stand"

Even though I dont feel the stand design is ideal, I would bet that it will work just fine as is. The stands that I see most of the time can support 2+ times the weight necessary for the tank that sits on them. Once you fill it up it won't be going anywhere.

Thanks for the calculations B!

 

[Dustin1300]

bct, appreciate the lengthy response and no one here is ever responsible for my actions and completely understand the disclaimer

Madreef, sorry but your not providing much value just saying it needs to be re-designed. I already have the base stand and am building up off of it. If you have constructive criticism on increasing it's strength it's appreciated, but coming in late to the game and saying it needs completely re-designed...Is not so helpful.

 

[Dustin1300]

One of the things I've consistently got feedback on is that this is a lot of weight displaced on a small area. To feat this, I'm going to use a platform (2X4s and 2X8s) to build the stand upon which will help distribute the weight better. Below are some of the details


Steel Stand:
2(96X2) + 2(44X2) = 560 square inches


With Treated Lumber:
2(96X7.25) + 3(32X7.25) + 4(33.5X3.5) + 6(9.625X3.5) = 2,759.125 square inches

 

[Madreef]

bct, appreciate the lengthy response and no one here is ever responsible for my actions and completely understand the disclaimer

Madreef, sorry but your not providing much value just saying it needs to be re-designed. I already have the base stand and am building up off of it. If you have constructive criticism on increasing it's strength it's appreciated, but coming in late to the game and saying it needs completely re-designed...Is not so helpful.

That's not what I'm saying at all. I'm saying the stand could have been built differently in a more ideal way. The stand you have is fine, continue on with your wild goose chase Dustin. If you don't like people posting in your thread then don't ask for input.

 

[Dustin1300]

That's not what I'm saying at all. I'm saying the stand could have been built differently in a more ideal way. The stand you have is fine, continue on with your wild goose chase Dustin. If you don't like people posting in your thread then don't ask for input.

Not trying to offend anyone here Not sure what the wild goose chase is about but just was not getting constructive criticism from your earlier post. I just need to understand what you mean, as what I read just says re-design it.

 

[Young Frankenstein]

Think of this, the acrylic or glass will fail before the concrete or steel will go.

 

[Dustin1300]

Think of this, the acrylic or glass will fail before the concrete or steel will go.

Honestly, I don't want to think of that at all! That would be a bad day, might be the end of the marriage....

 

[Dustin1300]

Been busy lately and this got put on back burner until beginning of this week when I sent off cut lists of what I needed on steel. Still waiting on the steel but having a few friends over tomorrow to assist in taking this beast off the stand and onto furniture movers so I can start working on this thing! If anyone is interested in the build here is thread and below is stand I went with. A Reefaholic's 1000+ Gallon Mixed Reef System Build

I appreciate all the input and help in making the design. The reefing community has many great resources and trying to visit multiple forums so I get more opinions

Added wood platform to better distribute the weight to the concrete.

 

[Engloid]

That only comes out to 138lbs per sq ft being exerted onto the floor....but that is with equal weight distribution over the 38 sq foot footprint. I would reccomend the gussets in corners though....and probably putting about 8 adjustable feet on bottom. That brings weight to about 500lbs per foot....still a lot since the foot is going to be about 2" diameter. Putting a piece of 4"x4"x1/4" plate under each would be my advice.

As for the strength of steel, it will likely be a grade that has about 60,000-80,000 psi tensile strength.

But as mentioned already, integrity and size of the welds are very important.

 

[Engloid]

I would skip the wood platform, and go to several adjustable feet, which will also aid in leveling the tank. The problem with wood ....well....it can have varying compression weights and density, as well as the fact it will soak up water anytime you have a spill. This can result in mold issues, as well as rotting that can cause the wood to fail under the metal stand weight.

I always try to avoid or minimize anything on the floor that I can't. Get water out from under, because spills will happen.