I want to put a gantry crane in my shop, spanning 36' in length. there will be two 36' w6x20 beams (6"x6" i beams) 12' apart with a carriage hanging on the beams to carry the load. I am looking for input on load capacities on the long beams. I will be lifting granite slabs that can weigh as much as 1700lbs. if anyone knows how to run the correct calculations that would be very helpful thanks...
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over head gantry crane
- Thread starter csa
- Start date
dirtrunner0519
Well-known member
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- May 9, 2012
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This is what i have been looking at, might help.
https://cfsei.memberclicks.net/assets/docs/designguides/3_loadspan.pdf
or
http://webstructural.com/steel-beam-how-to.html
https://cfsei.memberclicks.net/assets/docs/designguides/3_loadspan.pdf
or
http://webstructural.com/steel-beam-how-to.html
PAToyota
Well-known member
I’d really be contacting a structural engineer about something like that than asking for input from the internet...
Hilltopmasonry
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- Oct 12, 2015
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Yea you need to have a pro spec that out...36 feet span is huge...
1800 lbs is not that much but trying to span that much needs to have the right size beams
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1800 lbs is not that much but trying to span that much needs to have the right size beams
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ilovevocs
Well-known member
36' is a large span.
I wouldn't rule out a used fork truck as an option either.
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I wouldn't rule out a used fork truck as an option either.
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I appreciate the concern, I already had a single beam spanning 24' in the same spot. unfortunately my entire roof collapsed under snow load . My new design would be much stronger than what I had before and cover a greater area. I was hoping someone had and understands how to operate the soft ware to give the accurate capacities i am after.
ilo.. fork lift is great use it all the time, but in the shop I need to move things quickly and accuratly. my previous overhead did a good job for me just trying to improve on things during the rebuild.
p.s. my shop went down with thousands of other buildings in the area not because of the crane. there was no load on it at the time.
ilo.. fork lift is great use it all the time, but in the shop I need to move things quickly and accuratly. my previous overhead did a good job for me just trying to improve on things during the rebuild.
p.s. my shop went down with thousands of other buildings in the area not because of the crane. there was no load on it at the time.
I beam is load rated by the thickness of the web and dimensions. Most manufacturer's web sites will give charts with these specs and varying lengths. You'll need to add the carriage and hoist weight plus bounce, sway and safety margins to the equation but as long as you over build you should be fine.
matt_i
Well-known member
Not big enough imo. You are going to need some serious $ to make this work.
The beam you specify would have around 2-1/4" deflection under load in the center as well as being very dangerously close to fail in 36ksi steel. You will not be able to roll the load up out of the valley created. You have to remember that runway rails have to take the entire load if the hoist is placed at either extreme end of the bridge rail. The load never raises smoothly enough to prevent some kind of impact, whether it be chainfall hoist or a powered one.
Aside but related, I calculated the steel needed in my shop for a 25x40 bridge crane 3000lb cap, with 6 posts as I have a hoist with a powered trolley. I got a ballpark of around $5k. This is just for the steel structure. No track, no cable, no controls. Its a large fabrication which needs a careful layout & fabrication to be within about 1/8" of parallel and level. You should design it for L/480 deflection or better and you should use a P.E. which I am not, to approve the design.
The beam you specify would have around 2-1/4" deflection under load in the center as well as being very dangerously close to fail in 36ksi steel. You will not be able to roll the load up out of the valley created. You have to remember that runway rails have to take the entire load if the hoist is placed at either extreme end of the bridge rail. The load never raises smoothly enough to prevent some kind of impact, whether it be chainfall hoist or a powered one.
Aside but related, I calculated the steel needed in my shop for a 25x40 bridge crane 3000lb cap, with 6 posts as I have a hoist with a powered trolley. I got a ballpark of around $5k. This is just for the steel structure. No track, no cable, no controls. Its a large fabrication which needs a careful layout & fabrication to be within about 1/8" of parallel and level. You should design it for L/480 deflection or better and you should use a P.E. which I am not, to approve the design.
Last edited:
iron_worker
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I am a PE and I agree with matt_i that deflection will definitely be your limiting factor given what you have described. I did not find stress to be as much of an issue but I had to make quite a few assumptions so I cannot say for certain.
If you wanted a more specific answer you'd need to give some more information about your specific design like carriage weight, beam material (if already selected), etc.
IronWorker
If you wanted a more specific answer you'd need to give some more information about your specific design like carriage weight, beam material (if already selected), etc.
IronWorker
great thats the feedback i am looking for. The carriage will weigh about 810 with trollies hoist everything. I will be at the steel supplier today and will get more detail's on the beam selection, I will choose larger beams and post details tonight. My goal is to have this over engineered . The cost of the 6x6 beams @ 80' was 1600.00. I will let you know what the cost is on the larger materials tonight
matt_i
Well-known member
Keep in mind just because you sized a set of 3 beams, its not a bridge crane. The runway rails can't just sit on a post, there has to be appropriate pieces to keep the thing from racking in either direction as the load is moved. I don't know if you are trying to underhang the bridge rail or its going to be a top-running design...both have their challenges.
Imo its going to be cheaper and far easier to call up Gorbel and buy a pre-made structure system rated for the load, you bolt it to the concrete, erect it, and supply the hoist. They are on the "lighter end" of the bridge crane world, far from the 50 ton monsters which seem to cover an acre of ground.
Imo its going to be cheaper and far easier to call up Gorbel and buy a pre-made structure system rated for the load, you bolt it to the concrete, erect it, and supply the hoist. They are on the "lighter end" of the bridge crane world, far from the 50 ton monsters which seem to cover an acre of ground.
PAToyota
Well-known member
^^ This. Calculating out a beam is a lot different from calculating out things for a gantry crane.
I’m thinking there is a reason why your last setup collapsed… No idea where you are, but building codes likely have something to say about it as well.
I’m thinking there is a reason why your last setup collapsed… No idea where you are, but building codes likely have something to say about it as well.
iron_worker
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- Mar 15, 2011
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Its true. There are many things to consider. We were only discussing the one aspect which is the main span beams being able to handle the load. The deflection of the main beams will cause the ends to be at an angle as well as the effective length of the beam will be slightly shorter which will affect how the wheels will sit on the rails. The tracks themselves will tend to deflect as well. There are many things to consider and it all has to be designed to work together in all situations including how it affects your building and foundation.
IW
IW
rsanter
Well-known member
Do you need that to be completely free span or can there be a couple center support posts?
Bob
Bob
Here's an interesting build starting at post 53. Not as big but still interesting.
http://www.garagejournal.com/forum/showthread.php?t=2122&highlight=crane&page=3
Also check around for used ones. They are the kind of thing not everyone is looking for at the time someone else needs to sell one.
http://www.garagejournal.com/forum/showthread.php?t=2122&highlight=crane&page=3
Also check around for used ones. They are the kind of thing not everyone is looking for at the time someone else needs to sell one.
I am able to have supports along the length if I build it like OldCarguys. The legs of the crane will not be set on wooden posts. There will 30" reinforced footings with box tubing .500 wall.
the i beam i am thinking is s10x35 10" tall 4.994 wide .491 thick flange .594 thick web.
p.s. again the snow took down my building witch in turn took down my crane. Thousands of building went down in our area of southern Idaho and eastern oregon. Thanks
the i beam i am thinking is s10x35 10" tall 4.994 wide .491 thick flange .594 thick web.
p.s. again the snow took down my building witch in turn took down my crane. Thousands of building went down in our area of southern Idaho and eastern oregon. Thanks
X2, not something to be taken lightly.No pun intended, as we all tend to overload things from time to time and if your on the edge of the design now and oops it then there is usually a big crash followed by lots of oh S***T if your lucky.
X2, not something to be taken lightly.No pun intended, as we all tend to overload things from time to time and if your on the edge of the design now and oops it then there is usually a big crash followed by lots of oh S***T if your lucky.
This is funny given your screen name! LOL! "Why Worry?"