Sizing an I-Beam That's Resting On The Ground
Sizing an I-Beam That's Resting On The Ground
(OP)
All,
I'm a mechanical engineer at a steel mill and today I was asked to design a rack which will hold steel coils (see the attached picture). The coil rack shown in the picture is in use at a sister mill whose coils weigh only 50,000 lbs whereas our coils weigh up to 90,000 lbs. As you can see, the beams are resting on the ground. I'm at a loss as to how to calculate the required beam size to support these coils. We have various sizes of W 14 on-site and would like to see if any of those sizes would suffice. The project originator would like to use a beam that would not require web stiffeners or "boxing in the beam" which would consist of a plate welded to on both sides of the beam flange. With that being said, do you guys have any advice for calculating the required beam section? I'm most worried about the beam's web failing. Keep in mind that the weight of the coil will be shared over two I-beams, just as the attached picture shows.
Stuff you may want to know:
1. The beam's bottom flange rests completely on the ground.
2. The beams will be tied together at both ends.
3. There will not be chocks in place between the coils, this allows us to use free rack space most efficiently.
4. There will not be a compressible "padding" on the top surface of the beam i.e. no wood or rubber.
5. The overall length of the rack will be 30 ft.
6. There will be 42" in the clear between the two parallel beam's flange edges.
I'm a mechanical engineer at a steel mill and today I was asked to design a rack which will hold steel coils (see the attached picture). The coil rack shown in the picture is in use at a sister mill whose coils weigh only 50,000 lbs whereas our coils weigh up to 90,000 lbs. As you can see, the beams are resting on the ground. I'm at a loss as to how to calculate the required beam size to support these coils. We have various sizes of W 14 on-site and would like to see if any of those sizes would suffice. The project originator would like to use a beam that would not require web stiffeners or "boxing in the beam" which would consist of a plate welded to on both sides of the beam flange. With that being said, do you guys have any advice for calculating the required beam section? I'm most worried about the beam's web failing. Keep in mind that the weight of the coil will be shared over two I-beams, just as the attached picture shows.
Stuff you may want to know:
1. The beam's bottom flange rests completely on the ground.
2. The beams will be tied together at both ends.
3. There will not be chocks in place between the coils, this allows us to use free rack space most efficiently.
4. There will not be a compressible "padding" on the top surface of the beam i.e. no wood or rubber.
5. The overall length of the rack will be 30 ft.
6. There will be 42" in the clear between the two parallel beam's flange edges.





RE: Sizing an I-Beam That's Resting On The Ground
RE: Sizing an I-Beam That's Resting On The Ground
RE: Sizing an I-Beam That's Resting On The Ground
RE: Sizing an I-Beam That's Resting On The Ground
Cheers
Greg Locock
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RE: Sizing an I-Beam That's Resting On The Ground
RE: Sizing an I-Beam That's Resting On The Ground
Do this: Use 3x WF 14, not 2. The moment arm rolling the two end beams is reduced to 1/4 it previous value, and the load trying to buckle each web of the WF14's is reduced to 66% its previous value. Your problem is simplified.
RE: Sizing an I-Beam That's Resting On The Ground
You could treat the ground as elastic; you could use uniform load distribution on the ground. With the elastic foundation, the reaction directly under a point load would be higher, which should reduce the moment in the beam. So assuming uniform loading on the soil side should be conservative. And you likely don't have elastic stiffness for the soil side anyway.
RE: Sizing an I-Beam That's Resting On The Ground
"Schiefgehen will, was schiefgehen kann" - das Murphygesetz
RE: Sizing an I-Beam That's Resting On The Ground