calling engineers..steel stand

mylittleocean · #1 07/27/2004, 10:15 PM

I am planning on building a steel stand for my 180 gal. tank. Are there any engineers out there that can give me advise on this? I want an open front or a removable brace. Back can have a center brace or two. It wil be out of 1 x 2 x 1/8 steel tubing.? Here is a pic of what I have came up with sofar. I need to build in a couple weeks.

Thanks for the help.

if any engineers want to design a steel stand for me and other RC members that would be great. I have done searches and find few results, none with an open front. I am worried about the sag (displacement?) in the center that will cause stress on the glass tank.

Thanks again

mylittleocean · #2 07/27/2004, 10:17 PM

MargaritaMan · #3 07/27/2004, 10:21 PM

That will work. My 180 has a steel stand out of 1.5 x 1.5 x .0125. Uprights on all four corners and one center front and rear. Powder coated. MM

mylittleocean · #4 07/27/2004, 10:29 PM

can I do it w/o the front center brace and use this 'ladder' beam front?

Yep, it will be powder coated. =) My brother can do it.

bulldogfish · #5 07/27/2004, 10:52 PM

mylittleocean

I think with the ladder design you should be ok. But if you want to make double sure add some gussets to the inside of the ladder on the outside corners.

HTH

mylittleocean · #6 07/27/2004, 11:11 PM

Quote:

Originally posted by bulldogfish
mylittleocean

I think with the ladder design you should be ok. But if you want to make double sure add some gussets to the inside of the ladder on the outside corners.

HTH

sorry for my ignorance....gussets?
make triangles in the ladder?

davetkoch · #7 07/27/2004, 11:25 PM

Gussets are 45 degree triangular pieces that you can weld on to brace the frame against lateral instability. Imagine a house of cards and applying a force to the side...

If you wanted to get super heavy-duty, you could increase the strength of your beam by welding in diagonal truss members, but your vierendeel truss should be fine enough. Just make sure you have good welds.

davetkoch · #8 07/28/2004, 01:31 AM

Because I was bored and always enjoy helping a fellow reefer...

Above is a graphical analysis of the deflection in your design, with a zoom of the portion of the span experiencing the greatest moment. This was done with a great little structural engineering program called Visual Analysis for which you can get a 30 day trial if you are so inclined.

For simplicity's sake, I took half of that 2000lb load and applied it to each long span, since the short front to back spans aren't really assuming much of the max moment. I used 1x2x1/8 HSS and ASTM A500 Grade B steel(which should be about the strength of what you will be using) for the calculations.

Your greatest deflection with a 2000lb total load will be right around .035 inches at top and bottom of the truss. This assumes good moment(rigid) connections throughout the frame. The gussets are your call, but will undoubtedly improve the safety factor of these connections.

OH and BTW, a back brace won't be necessary.

Cheers and sleep well knowing what a TANK your stand will be.

-Dave

mylittleocean · #9 07/28/2004, 03:07 PM

So that is like 1/32" sag in the middle? right.
That should be OK (I hope). I just dont want to cause any stress on the glass tank over time. With a plywood (MDF rather) on top everything should be OK.

I will post some pics of my progress.

THANKS for the help all

Thankyou for your time Dave

gobygoby · #10 07/28/2004, 03:34 PM

one more tidbit, I have a 180 that has a steel frame for it, i thik it has 1.5 square tube. it only has the for legs...no center legs and it was just fine...

if you want pics email me
gobyfish04@aol.com
Kyle

mylittleocean · #11 07/28/2004, 03:40 PM

Intsead of the 'ladder' would this be any stronger? Triangles are stronger than squares right.?

I would like to see the pics if you dont mind. I will sent you a PM.

Thanks

davetkoch · #12 07/28/2004, 07:07 PM

I'll check out the behavior of both a 2 and 4 panel truss design and get back to you.

-Dave

MargaritaMan · #13 07/28/2004, 07:29 PM

Dave, Nice work! Mom and Dad would be proud, several tens of thousands of dollars on an education and now you can make aquarium stands!

j/k Seriously, that is the kind of info we need more of on this board, actual fact, not someone's best guess.

MM

davetkoch · #14 07/28/2004, 07:38 PM

OK...

Quickly simulated 2 and 4 panel Pratt truss. As expected the 2 panel version suffers from greater deflection than the Vierendeel truss due to the longer span of each panel. The 4 panel Pratt, however, will deflect only .004" under a 2000 lb load thanks to the addition of the diagonals. Analysis shown below.

Essentially, you can double the loading and still be at only .007 inches deflection. How's that for strength.

BTW, one more thing I would change: Add a diagonal brace or gussets to the side of the stand as shown in the revised elevations below. The choice is up to you as either works. This will add additional lateral stability to the weak orientation of the structure.

Cheers,
-Dave

mylittleocean · #15 07/28/2004, 07:50 PM

Quote:

Originally posted by davetkoch
OK...

Quickly did calculations for 2 and 4 panel Pratt truss. As expected the 2 panel version suffers from greater deflection than the Vierendeel truss due to the longer span of each panel. The 4 panel Pratt, however, will deflect only .004 under a 2000 lb load thanks to the addition of the diagonals.

Essentially, you can double the loading and still be at only .007 inches deflection. How's that for strength.

Cheers,
-Dave

I can live with that. Thanks for the help.
I will do the 4 panel Pratt.

Future RCers will thank you too. I have seen no threads or research on this. All I read is 'I think it should work', its nice (comforting) to get some real fact. Countless $$$ invested puts alot of fear in me.

Thanks again

davetkoch · #16 07/28/2004, 07:56 PM

No problem, always happy to help. The engineering classes DO come in handy.

IMO here's nothing more efficeint and elegant than a good ole' truss.

Oh BTW--I just edited the above post with a suggestion for bracing the side of the tank against lateral instability.

Check it out.

-Dave

davetkoch · #17 07/28/2004, 08:30 PM

MargaritaMan,

Ah yes, the fruits of my education. If only it were Mom and Dad's money... Heheh--loans.

On the bright side, my parents ARE able to afford to pay the quarterly interest. I keep telling myself that I need to patent something to make some extra cash, or maybe I can start building aquarium stands on the side.

flamereefer · #18 07/28/2004, 08:37 PM

where do you buy the steel for these stands?

mylittleocean · #19 07/28/2004, 08:41 PM

I have a metal yard in town. Industrial supply

davetkoch · #20 07/28/2004, 08:42 PM

Google for "steel tubing" and you will find some manufacturers and distributors. Otherwise, if you know someone who can weld or is in the construction industry they should be able to obtain HSS(Hollow Steel Shape) tubing. Maybe some of the other RCers can help you out with some specific suppliers.

mylittleocean · #21 10/28/2004, 05:41 PM

For those interested, I have finished the stand.
I have a thread going on my new setup (slow moving right now).

http://archive.reefcentral.com/forum...hreadid=452029

Alfalfameister · #22 06/10/2005, 10:27 AM

Quote:

Originally posted by mylittleocean

Future RCers will thank you too. I have seen no threads or research on this. All I read is 'I think it should work', its nice (comforting) to get some real fact. Countless $$$ invested puts alot of fear in me.

You bet "Future RCers will thank you too"!!!

Thanks, davetkoch! Been looking for info like this!

Alfalfameister · #23 06/11/2005, 07:30 PM

Hmmm... now that I brought this up again, if I do the triangulation style (4 channel pratt), can I do away with the back center vertical brace altogether?

macro · #24 06/12/2005, 06:35 AM

no .you should put some support back there.u can for example ,go out from 7"from the end and put to vertical peices one on each end.11 11