Reaction forces at any point
Reaction forces at any point
(OP)
Hi,
I'm trying to calculate the reaction forces on a vertical continuous beam (seawater caissons on offshore platforms if anyone's interested). I'm doing this in Excel. So far I've been able to calculate everything up until deflections if the beam was a cantilever but I'm not sure how to calculate the deflections when they're fixed at the supports annotated in the diagram (red arrows). Any ideas on how to go about doing this in Excel?
I'm trying to calculate the reaction forces on a vertical continuous beam (seawater caissons on offshore platforms if anyone's interested). I'm doing this in Excel. So far I've been able to calculate everything up until deflections if the beam was a cantilever but I'm not sure how to calculate the deflections when they're fixed at the supports annotated in the diagram (red arrows). Any ideas on how to go about doing this in Excel?






RE: Reaction forces at any point
RE: Reaction forces at any point
Consider the beam simply supported at the upper and lower supports. Calculate deflection Δ at middle support due to the applied load. Calculate end reactions.
Under the action of a unit load, calculate deflection Δu at middle support due to unit load. Calculate reactions due to unit load.
Calculate reaction at middle support, R2 = Δ/Δu.
Adjust end reactions for R2.
BA
RE: Reaction forces at any point
RE: Reaction forces at any point
RE: Reaction forces at any point
you could analyze as a beam, cantilevered at the base with two supports (doubly propped cantilever). This is doubly redundant, but the singly propped cantilever is a well known book solution, so then it's "only" a matter of using displacements of the singly propped cantilever to determine the reaction at the second prop (unit load method). you can solve your structure two ways to check your solution. This solution allows the beam to develop it's "correct" internal moment, as a continuous beam, probably less than your fixed assumption.
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RE: Reaction forces at any point
BA
RE: Reaction forces at any point
RE: Reaction forces at any point
BA
RE: Reaction forces at any point
I think BA's point is that nothing is truly fixed, but then it seems you're doing a hand calc to verify a FEA ?
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RE: Reaction forces at any point
I should've been a bit more clear, those three points were arbitrary points and depending on the situation, there can be more or less of them. I just put them there as an example.
RE: Reaction forces at any point
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