Bridge Crane designs and ideas...38' span

[LD1]

Trying to plan out and decide how I want to build my bridge crane in the shop.

I cannot afford a new beam big enough for the 38' span. So will wait til the right one comes along on craigslist or whatever. There are some good ones on there now so I though I'd run some ideas by the board.

My main concern is with a 38' span, its gonna take a HEAVY beam, or a TALL beam, or a combination of both.

The HEAVY beams in the 16-18" range would be nice if I could find one. My concern with a taller beam is hanging a load from the bottom, and in order to move it you are pushing and pulling on the chain "twisting" the beam possibly causing the top to buckle.

I have colums, beams, and track for the main bridge to run on. It will have 12' of run, the a push-trolley on the 38' span. According to my math, minimum beams needed for a 10k max load SF are
5:1 SF....................3:1 SF
W12x106...............w12x72
W14x99.................w14x61
W16x89.................W16x57
W18x86.................W18x55
W21x83.................W21x50
W24x68.................W24x55

Ill probably never ever lift 10k, but my chain hoist is a 5t

Current craigslist beam offerings are:
W24x104 39' long. Overkill and more than I want to spend @ $1250 but would get the job done for sure if I can get it up there.

W12x72....2 of these 25' long each. Good price. $600 for both. Could be welded together, but under the 5:1 SF most cranes are designed for. Could take the extra 12' and weld to the top in the middle to gain some strength and bridge over the seam of splicing them together.

W24x84 38' long. Will easily handle the load and be easier to lift than the W24x104, but is about 3x weaker in the horizontal direction, and cost just as much. So for the price, I'd rather get the heavier beam and worry about setting it.

S12x35....30' long but he has 7 of them. I dont normally like S-type beams for long spans as they are too narrow and easier to twist or deflect in the horizontal direction with a single beam span and no flooring or nothing tying in multiple beams. But I have a crazy idea about attaching 3 of them together. Look at the picture for a cross-section:



Being two wide would solve the problem of S-type beams being weak in that direction. The bottom beam to gain depth would "probably" get the strength I need, but cannot find any formulas for stacking beams. The bottom beam would actually be about 1' shorter on each end, as the top two beams would extend and set on the "truck" that is riding on the rail.

My gut says this would be a sufficient setup, as overall depth would be 24" and plenty heavy. But the best part is this would cost me under $500 , and I could set them in place a beam at a time

Thoughts, Opinions, Am I crazy?

 

[ishiboo]

What in the world do you need such a huge span/weight capacity for?

The HEAVY beams in the 16-18" range would be nice if I could find one. My concern with a taller beam is hanging a load from the bottom, and in order to move it you are pushing and pulling on the chain "twisting" the beam possibly causing the top to buckle.

You're going to need to go tall.

I don't quite get what you mean by pushing/pulling on the chain. You plan on moving a 38' bridge crane by pulling on a chain attached to it from the ground? That's a pipe dream. It will need to be motorized on both ends. Even if you got it moving, you wouldn't be able to stop it or move it accurately enough for any purposes. The W24x104 would be almost 4,000 lbs. You think you can move that by pulling on a chain?!

This sounds poorly thought out.

 

[LD1]

You think you can move that by pulling on a chain?!

With 8 or 10" steel rollers running on a steel rail track, yes I do think I can move it. We have a 25 Ton bridge crane at work. Two guys can easily pull it along when the brake is released.What I mean by pushing or pulling on the chain is the same way you move a manual trolley with a chain hoist attached. It isnt that hard to roll 5000# on a push trolley with 4" wheels closely spaced. Why would this be any different. Just a little heavier, but certainly movable.

In reality, most of the stuff I lift will probably be a ton or less. But like the capability to lift more if the need arises. I dont want to be limited by my hoist

Long term plans is to make it driven either motorized or with a manual chain, but either way, the point is the same. Taller lighter beams arent really resistant to the twisting forces.

 

[4570Man]

My little 1/2 ton hoist that weighs a few hundred pounds is hard to pull on the beam. If your hoist weighs 2 ton I think you are dreaming of pulling it by hand.

 

[ishiboo]

With 8 or 10" steel rollers running on a steel rail track, yes I do think I can move it. We have a 25 Ton bridge crane at work. Two guys can easily pull it along when the brake is released.What I mean by pushing or pulling on the chain is the same way you move a manual trolley with a chain hoist attached. It isnt that hard to roll 5000# on a push trolley with 4" wheels closely spaced. Why would this be any different. Just a little heavier, but certainly movable.

In reality, most of the stuff I lift will probably be a ton or less. But like the capability to lift more if the need arises. I dont want to be limited by my hoist

Long term plans is to make it driven either motorized or with a manual chain, but either way, the point is the same. Taller lighter beams arent really resistant to the twisting forces.

I think the thought of pulling it by hand with 1 person off the chain (remember you are extorting force both to move the beam AND pulling it down) is a joke, but you'll find out if you try it

The concern for "twisting forces" when you pull it is equally unfounded. That is a very large beam, you're not going to twist it by pulling it or pushing it.

The carriages/trolleys that mount the beam to the tracks on each end need to be rigid and keep the beam perpendicular to, and on the tracks at all times. They will need rather expensive rollers to carry the weight and avoid this.

Stopping and starting the load, swinging, etc. are all major concerns. Most steel shops don't have a 38' span 5T because it's cost prohibitive. Still curious about why you need one and what you plan on doing with it.

 

[LD1]

Stopping and starting the load, swinging, etc. are all major concerns. Most steel shops don't have a 38' span 5T because it's cost prohibitive. Still curious about why you need one and what you plan on doing with it.

Pulling motors, splitting tractors, loading and unloading odd stuff from the truck and trailer, all sorts of odd jobs.

I had a 30' span beam good for 8k at my old shop. No bridge, just a single span trolley. Its limitation was only moving in 1 direction. Heaviest thing I lifted there was a complete backhoe attachment off a ford 3400 and loaded it onto a trailer. Probably 5000-6000#.

First order of business for the new hoist is going to be pulling the motor out of my Ford 5500 backhoe, and likely removing the backhoe and loader and doing some other work to it. 5t is probably overkill, But I would want no less than 3t for sure.

 

[rswyan]

Dunno how far you are willing to travel or whether any of these would meet your needs (or budget) but these have been on craigslist for quite awhile ... coming out of an old Delphi plant up in Cortland, north of Youngstown:

H and I Beam -- Structural Steel - Crane Rail

 

[LD1]

I saw those.

Bit pricey for what they are. And yea, far. The S18x70 is close, but I still dont like a beam that tall in a S-type without some other support.

The two W-beams listed are lighter than needed for 5-ton. load, but the W18x50 is close.

 

[4570Man]

It doesn't take anywhere near a 38 foot span to do the described tasks. A crane one foot wider on both sides of your garage door could do that.

 

[LD1]

It doesn't take anywhere near a 38 foot span to do the described tasks. A crane one foot wider on both sides of your garage door could do that.

building is 40'

This isnt going to be a roll around gantry thing, rather a permanent structure. Dont want posts out in the middle.

 

[notme]

drop down to a smaller chainfall... one ton (2000lb) is probably lots for most motors or anything else you would want to move.....redesign from there! u will find your beam sizes much more affordable...anything bigger then that use your loader bucket or another piece of machinery..i cant see it being a regular occurance. just my 2 cents

 

[CNC Dan]

Have you considered zigzag cutting the web on a beam, offsetting it and re-welding, to make a taller, stiffer beam than what you started with.

cellular castellated beams - Google Search

 

[LD1]

Have you considered zigzag cutting the web on a beam, offsetting it and re-welding, to make a taller, stiffer beam than what you started with.

cellular castellated beams - Google Search

That looks like a TON of work. I would rather just take two beams and stack them I think.

 

[Industrial Toys]

I knew someone that built one with about a thirty foot span. He had be problems in the rod that drove the wheels acting as a torsion bar and so one side would outdrive the other and the thing would get jammed up. I don't remember how they fixed it but it was a giant PITA.

Just something to think about.

I would love to have a bridge crane. That's about the nicest toy a man could ever have!

 

[LD1]

If I did a manual drive with a chain and wheels, the drop chain would be in the middle. So the torsion effect would be balanced.

 

[Bladehauler]

Are You dead set on a bridge crane . Seems a good size forklift could fit the bill with a crane attachment off the forks . Might be cheaper in the long run .just my .02

 

[LD1]

Are You dead set on a bridge crane . Seems a good size forklift could fit the bill with a crane attachment off the forks . Might be cheaper in the long run .just my .02

IF I can get a beam for ~$600-$800, thats all I need. I have everything else.

And not much to go wrong with a crane, and maneuverability is never an issue, or changing oil or other engine up keep.

 

[ultrarunner]

The bridge crane at the shop had a geared wheel with a chain to move it... shop was 150 long in the assembly area.

 

[CNC Dan]

That looks like a TON of work. I would rather just take two beams and stack them I think.

It is a bit of work, but you would just make a template to cut a few feet, then reposition. And it wouldn't add any weight.

It would be quicker to just add a square tube to the top. Would help with torsional rigidity too.

 

[RedNeckRacin]

LD, maybe I missed something but you said "It will have 12' of run, the a push-trolley on the 38' span" Why don't you turn the design and make the 12' span the bridge and put your posts in the other direction so that you can use smaller material all the way around??


Also, your deflection calculation is most likely going to control your beam design as long as their isn't a localized failure in the flanges of the beam due to the high point loading from the very small trolley wheels. Also, don't forget that if you have to much deflection center span, that the beam could potential rotate off the running gear at the ends or at the least bind it up. Also, don't forget to look at lateral torsional buckling when you get tall slender sections.