Jj1479
Silver Member
Bridge Crane designs and ideas...38' span
- Thread starter LD1
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Jj1479
Silver Member
Jj1479
Silver Member
I think this is what you are wanting to build.
OP
LD1
Epic Contributor
Spot on. What size and span is that beam.
bigdeano
Platinum Member
Just to confuse things, if you had a trolley that ran on top of the beam you could make the beam into a truss with a rod underneath. You'd lose some lifting height though. Seems like it could be a lot lighter and cheaper. Carry on.
Jj1479
Silver Member
not sure I just did a Google search for single girder overhead crane. To scare everyone like you I to built my own 2 months ago an it works fine. 6" I beam 29' long with 1/4" web. I beveled an welded 2 pieces of beam together with fish plate over the seam on both sides. I have a CM Loadstar 110volt 500lb capacity hoist (that is turned up/modified) with roller trolley on it an it lifts the front of my Kubota bx25 with loader an backhoe up until the backhoe hits the ground. We also just lifted the rear of my 2001 ford ranger xlt today to replace the spring shackles. So at least 1500lbs I figure cause the whole machine weighs 3172 with my bigger bucket an the truck is 5034lbs. The beam is sitting on 4x6 treated post that have angle welded to the beam an the angle is bolted through the posts. The beam is also safety chained to the header beams that the roof trusses are mounted to so there is no way of it coming down. With the machine lifted we were just at 1" of deflection in the center of 29'. Attached are pics when I first built the beam.
Last edited:
OP
LD1
Epic Contributor
It wouldn't scare me without putting number to paper and knowing the exact beam. So I'll reserve judgment til I get home and do that in the morning. Assuming 6" web also? What's the web thickness?
Is the beam 29' or the span? If the beam is 29 and on 6" posts, San would be 28'.
Not sure what you mean by the safety chains.
I am still looking and hoping I find a beem soon. Otherwise I'll probably just get a new on at the 50 cents a pound I have been quoted from any of about 3 or 4 suppliers.
Is the beam 29' or the span? If the beam is 29 and on 6" posts, San would be 28'.
Not sure what you mean by the safety chains.
I am still looking and hoping I find a beem soon. Otherwise I'll probably just get a new on at the 50 cents a pound I have been quoted from any of about 3 or 4 suppliers.
OP
LD1
Epic Contributor
It wouldn't scare me without putting number to paper and knowing the exact beam. So I'll reserve judgment til I get home and do that in the morning. Assuming 6" web also? What's the web thickness?
Is the beam 29' or the span? If the beam is 29 and on 6" posts, San would be 28'.
Not sure what you mean by the safety chains.
I am still looking and hoping I find a beem soon. Otherwise I'll probably just get a new on at the 50 cents a pound I have been quoted from any of about 3 or 4 suppliers.
Is the beam 29' or the span? If the beam is 29 and on 6" posts, San would be 28'.
Not sure what you mean by the safety chains.
I am still looking and hoping I find a beem soon. Otherwise I'll probably just get a new on at the 50 cents a pound I have been quoted from any of about 3 or 4 suppliers.
Jj1479
Silver Member
yes 6" web 1/4" thick. Your rite 29' total so 28' span. I cut a 2" hole in either end of the beam center web an ran a chain through the steel beam around my roof truss beam that are made out of 2x12s. It's a safety feature just in case someone backs there car in an accidentally hits into one of the posts an sheers it off the beam will not fall. My post sit on the cement floor and are lag bolted into the 6x6 posts that are cemented into the ground.
OP
LD1
Epic Contributor
I meant to ask about the flanges. (thats where the strength is). ASsuming its 6" x ~1/4" also, that makes it a W6x15# beam.
For my calculations I was using A36 steel with 36ksi yield strength. So a 5:1 safety would limit allowable to 7200psi. Most beams are actually a992 which is 50ksi so a 5:1 would allow 10ksi stress.
Assuming the beam above, a 1000# load would be 8660psi stress and 0.905" deflection. NO that would not scare me.
1500# is 13ksi stess and 1.36" deflection. While exceeding a SF of 5:1, still a good ways from failure.
For my calculations I was using A36 steel with 36ksi yield strength. So a 5:1 safety would limit allowable to 7200psi. Most beams are actually a992 which is 50ksi so a 5:1 would allow 10ksi stress.
Assuming the beam above, a 1000# load would be 8660psi stress and 0.905" deflection. NO that would not scare me.
1500# is 13ksi stess and 1.36" deflection. While exceeding a SF of 5:1, still a good ways from failure.
