I-Beam load capacity?

[ardent06]

I realize this sounds like cheating, but is it practical to buy a gantry? Wallace Crane (http://www.wallacecranes.com/gantries.htm) is one company that make portable gantries. I am very cautious about designing something to lift and carry heavy items around or over people. If you have a defined straight path you carry the load, you can put channel or track on the floor to guide the gantry.

Advantages: The beam can be short (size it to the load instead of the room). Someone else is liable for the design of beam and its capacity. You do not need to modify the building.

Disadvantages: You have to pay for it, but I do not know how that compares to modifying your building.

[lakeside]

well I used some I-Beam on my house (it was cheaper the lvl-beams at the time)

[JFettig]

BMA137, thanks for the correction, I bet your right.

Its possible that I screwd up and didn't remember what one to use, but its even more likely that my idiot teacher that has never had a job in the field, just got his degree and turned stupid taught us, I'm not just saying that, anyone who has had him would say that, my boss at work had him and says that.

I'll edit my post saying how its not correct and correct it.

Jon

[miljnor]

You guys are over thinking this quite abit!

just look at a commercially available trolly system that can lift what you want and COPY IT! (barring any patent infringment of course)

If the company has been in business for very long they have all of the math worked out for the load that is advertised! If they didn't they would have been litigated out of existence!

Not to mention if you want swinging stability you will probably need 4 trolly rollers spaced out so now you math gets more complicated buy the fact that you have multiple contact points spaced away from center. if you don't do the 4 trollies you will probably be wearing out components very quickly from the swinging force.

And who ever said a factor of 2 for building should maybe go to maybe a factor of 5 instead. As all you have to do to blow a factor of 2 is to bounce the load and you now got a big bow in your beam.

[DennisCNC]

^^ I like your thinking (are you Chinese?)

Thank you all for input of this!!
I'm renting the building that i'm in right now, I'll see how things are going to go before starting to put together a moster like that.


Dennis

[miljnor]

^^ I like your thinking (are you Chinese?)

dude!


It is legal to use even patented ideas for personal use!

I would never condone selling something that is a patented product (even if I disagreed with the patent issued)

copyrights however I have other opinions on!

[lakeside]

[QUOTE=DennisCNC(are you Chinese?) [/QUOTE]
He's not Chiness and I don't think He drinks there beer ether.

[tobyaxis]

^^ I like your thinking (are you Chinese?)

Thank you all for input of this!!
I'm renting the building that i'm in right now, I'll see how things are going to go before starting to put together a moster like that.


Dennis

Interesting Thread

[bma137]

JFettig, understood, I know exactly what you mean with your teachers.

[miljnor]

nope.

I dont drink chineese beer but if you got something I should try, give it up man!

[tobyaxis]

[QUOTE=lakeside]

He's not Chiness and I don't think He drinks there beer ether.

Off topic but what does Chinese Beer look and taste like? Schafers? Schmits? Dog Urine?

Miljnor could not possibly be Chinese, he writes english very well and I don't have a hard time understanding him.

[miljnor]

I am a Mutt but I don't believe chinees is in my pedigree.

as far as beers go. I don't drink alot of common beers as most tast like dog urine, but as far back as I can remember chinees are right up there with the common beers.

there are you happy lakeside? you are evil! changing yet another post into a beer post!

and I always get the blame! damn!

[ardent06]

You undergrads and recent grads are making me feel old!

Especially in a rented building, I still recommend buying a portable gantry. If you change locations, you disassemble the gantry, put the parts in a truck and take it to the new building.

If you use a short beam, you will have more usable headroom (more headroom is always better). Between the beam, the trolley and the hoist, headroom disappears quickly.

As a different approach, is it practical to get a cart of some sort under the load? It changes the problems a bit, but the part of the building that matters is the floor. It is something to ponder.

Deflection might be significant for you. When you lift the load and the beam deflects, the load will try to drift toward the center of the beam. Depending on the load and the deflection, the force could be large. You also have to overcome that force when you move the load away from the center of the beam.

In my experience, if a tool or piece of equipment is available off-the-shelf, it is usually less expensive in the long run to buy it than to build it in-house. Let the experts design and build it.

In this era of plentiful lawsuits, do not assume any liability needlessly (that is my PE license talking). Yes, you are still liable for selecting the proper equipment, assembling it properly, maintaining it properly and operating it properly, but you can avoid the problems designing the equipment, buying the proper materials (it that beam really the grade you think it is?) and fabricating it. You can also improve the safety of the equipment (and reduce your liability) by paying someone to inspect your lifting equipment, by locking it when no one is supposed to be using it (we had someone break the gearbox in a 5-ton hoist by misusing the hoist afterhours) and by teaching everyone who might use the hoist on how to use it correctly.

Oh, my goodness! I sound like the dreaded Safety Inspector! It has been that kind of a week already. In short, be careful and do not let your computations get in the way of your common sense.

Bob

[miljnor]

who would have though that a post on I-beam selection could get this out of hand?

aint life grand.

[lakeside]

Yes I should not talk about Beer
So to all you kiddies out there a mind like a good beer is a shame to waste.
I'm Irish and Polish so I have dumb luck

[pstoop]

I'm building a bridge for a 5 ton load (tractor and load of firewood)
It is a 20 foot span, and I've used 3 10inch I-beams (scrounged up for free)
I think it is overdesigned, but it would be interesting to know for sure.

I don't care about the amount of deflection (an inch or two is fine).
What is the deflection? Is it safe for a 5 ton load? Is it safe for a 10 ton load? Assume the load is at the mid-point.

This is probably a very simple calculation for those who have done it before.

Thanks
Pete

[martinw]

Dear Pete,

Presumably you thinking of arranging the beams "plank-wise"? Can you give any more information about the dimensions and properties of your beams?

Best wishes,

Martin

[Geof]

My engineering (???? lots of big questions marks because I am not an engineer) is done by seat-of-the-pants and gut feeling. And both of them are saying do not drive your five ton tractor, let alone your ten ton tractor over your three 10" I beam bridge at least until after you have written your will, assigned an executor and got all your affairs in order.

For bridges a good overload factor is maybe 5x so you should build something that can support a static load of 25 or 50 tons. That way when your 5 or 10 ton load bumps and bounces over it you do not overload it with the shock loads.

Find a reference website that will give you tables for the value of I for standard I beams and another site that gives you the formula for calculating the midpoint deflection of a simply supported beam and do the calculations. If your bridge is going to deflect more than about 1" with the 25 ton load I am not going to drive your tractor over it.

And if you don't know what I is or what a simply supported beam is don't build any bridges until you do.

[lerman]

dude!


It is legal to use even patented ideas for personal use!

I would never condone selling something that is a patented product (even if I disagreed with the patent issued)

copyrights however I have other opinions on!

What makes you think that you can legally "use patented ideas for personal use"? (And by the way, one can patent machines, one can patent methods, one cannot patent ideas.)

I'm not a lawyer, nor do a play one on TV; but I have interacted with patent lawyers.

Ken

[martinw]

Dear Pete,

Let's look at your bridge from another angle.

Is it a short piece of rough ground that needs to be a bit flatter for your tractor, or does is span a yawning 20 ft wide ravine that is 130 feet deep and has vertical walls??? If it is the latter, I personally would consider the consequences of structural failure a bit more seriously than if it was the former. (Mind you, a 5 ton load of metal and lumber toppling on to you even on a flat surface will probably have the same result).

End of party-pooper section....

OK, you say you have 3 12" deep I beams.

How wide are the top and bottom flanges, and how thick are they?

How thick is the web?

How far apart are the three beams, and what is the "deck" that forms the bridge?

Can you imagine a loading situation in which (say by driving the tractor in a wonky manner) only one of the three beams takes the load for a second or two.

Please do not get me wrong. I'm not trying to design your bridge, I'm just trying to find out if your beams are complete "no-hopers" or otherwise.

Best wishes,

Martin