Bridge Crane (with cantilevers!)

[ThePanzerFuhrer]

Thanks,

Those look like W beams. Seems like S beams (with the tapered flange) help to self align the trolleys to the middle. Unfortunately my beams are also W beams. My beams being so close together (8 feet) might help the bridge resist racking. Seems to me that the further apart the runways, the more tendency to rack. I can always add side bearings to one trolley and have the other trolley floating to accommodate out of parallel.

I've searched through a million threads online and everyone wants the same information, "what size beam do I need?"

Would be pretty cool to have a monster thread somewhere with info on existing installations:

What beam is used (height/type/weight)
Span
Load rating

Every thread seems to get the same generic answer---call an engineer.

In my case I guess a 6 inch S-beam 12.5 lbs/foot would work for a 2 ton rating.
If I was to go with 2 beams could I use 4 inch 9.5 lbs/foot?

What I did was just go to a jib crane guy and see what they used. They have spots where the beam size is spelled out. Now being a bridge you double the capacity the jib guys use. This will get you into the ballpark.

Taking to the guys who built the bridge crane in my shop he says they try to shoot for less than a .75” of deflection on my 30’ span at max capacity.

 

[Muckin_Slusher]

Found this:

https://www.yalehoist.com/Catalogs%20and%20Manuals/Yale%20Crane%20Components/YALE_CRANE_COMPONENT_-CRANE_BRIDGE_KITS_THRU_5_TON_MANUAL.pdf

If I'm reading correctly the chart is for "bridge girder" so it's what I'm looking for. Not 100% sure why they state the wheelbase of the end trucks (54 inch) I don't understand how that has much impact on the capacity of the bridge. Maybe because the longer trucks are better able to keep the bridge upright.

Anyway, seems that S6x12.5 is good for 10 foot spans up to 2000 lbs. So that's what I'm gonna shop for. Two S6x12.5 should give me a 4000 lbs rating and ability to put the hook up inbetween for highest lift height.

 

[IowaOffRoad]

If you have the money and don't need to get right up to the wall I always wanted to build one with 2 parallel beams with dual trolleys for the hoist riding on top of the parallel beams for the hoist. Should be able to get more head room, more spread between the trolleys on the side beams, and you can use shorter hoist beams for the same load over the span, or gain more capacity, or both.

 

[arse_sidewards]

I've searched through a million threads online and everyone wants the same information, "what size beam do I need?"

Would be pretty cool to have a monster thread somewhere with info on existing installations:

What beam is used (height/type/weight)
Span
Load rating

Every thread seems to get the same generic answer---call an engineer.

In my case I guess a 6 inch S-beam 12.5 lbs/foot would work for a 2 ton rating.
If I was to go with 2 beams could I use 4 inch 9.5 lbs/foot?

There's really no reason for this because every setup is different and if you know how much deflection is acceptable to you you can just plug various loads and beam sizes into an online calculator.

 

[arse_sidewards]

If you have the money and don't need to get right up to the wall I always wanted to build one with 2 parallel beams with dual trolleys for the hoist riding on top of the parallel beams for the hoist. Should be able to get more head room, more spread between the trolleys on the side beams, and you can use shorter hoist beams for the same load over the span, or gain more capacity, or both.

I'm thinking about doing this in my garage. Probably won't though because the perfect is the enemy of the good.