Beam on Top of Beam - not connected to each other
Beam on Top of Beam - not connected to each other
(OP)
How do you calculate Section and Moment of Inertia of 2 beams, one on top of the other beam, without being connected
to each other
to each other






RE: Beam on Top of Beam - not connected to each other
RE: Beam on Top of Beam - not connected to each other
I also think that you can not combine the two beam sections if they are not positively connected so that all forces can be shared.
I hope this helps
Lutfi
www.cdeco.com
RE: Beam on Top of Beam - not connected to each other
RE: Beam on Top of Beam - not connected to each other
corus
RE: Beam on Top of Beam - not connected to each other
If two unequal beams span the same amount, and deflect the same amount, the the bending moments and shears in each will be proportional to the relative stiffnesses of the two beams. So if beam A has an I = 100 and beam B has an I = 200, then beam B will take 2/3 (200/(100+200)) of the load and beam A will take 1/3.
If they aren't in initial contact, (a gap) then the top beam will take all the load until they come into contact, then the remaining load will be shared by the two as above.
All of these calculations are based on two distinct beams, each with their own Areas, moments of intertia, etc.
If you connect the two beams with adequate welds or bolts, then you prohibit the horizontal sliding I mentioned above and you've created a combined section - where you must calculate the total Area and Moment of Inertia for the two shapes made one.
RE: Beam on Top of Beam - not connected to each other
1. Both beams are the same length.
2. The bottom beam has simple supports. The top beam has no supports (other than the bottom beam).
3. Before any load is applied, the beams are in full contact along their entire lengths.
4. Assume no friction between the beams.
5. Vertical (down) load is applied to the top beam.
The calculated answer would be a reasonable and conservative approximation (most likely for several reasons). Probably the most important being that in "real life" there will be some friction between the beams. The actual deflection should be slightly less than calculated, but the defelection of both beams should still be equal.
RE: Beam on Top of Beam - not connected to each other
RE: Beam on Top of Beam - not connected to each other