- #1

FEAnalyst

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- TL;DR Summary
- How to solve this braced portal frame analytically?

Hi,

I'd like to find the easiest way to solve the following braced portal frame statically (at least for deflection and maybe stress if possible, no need to account for buckling here - reason explained below):

Of course, I could utilize symmetry:

But the problem is still that it's a statically indeterminate structure with a quite high degree of static indeterminacy - I assume no pinned joints.

Now the purpose is just to verify the results of the open-source FEA benchmark (so it's not an actual engineering case or homework). Thus, I will use FEM but I need an analytical solution as well. I was looking for ready-made formulas for such frames in books like Roark's but haven't found anything. Are you aware of such publications ? Those frames seem to be pretty basic after all.

If there are no ready-made formulas, I'm considering using some simplifying assumptions to make it easier. So maybe assuming all pinned joints (I wonder how inaccurate this assumption would be) or even solving the members one by one as individual beams but I'm not sure how to approach that. I'm aware that otherwise likely the only way would be to use the force or displacement method which is not easy and I don't have a civil engineering background.

I'd like to find the easiest way to solve the following braced portal frame statically (at least for deflection and maybe stress if possible, no need to account for buckling here - reason explained below):

Of course, I could utilize symmetry:

But the problem is still that it's a statically indeterminate structure with a quite high degree of static indeterminacy - I assume no pinned joints.

Now the purpose is just to verify the results of the open-source FEA benchmark (so it's not an actual engineering case or homework). Thus, I will use FEM but I need an analytical solution as well. I was looking for ready-made formulas for such frames in books like Roark's but haven't found anything. Are you aware of such publications ? Those frames seem to be pretty basic after all.

If there are no ready-made formulas, I'm considering using some simplifying assumptions to make it easier. So maybe assuming all pinned joints (I wonder how inaccurate this assumption would be) or even solving the members one by one as individual beams but I'm not sure how to approach that. I'm aware that otherwise likely the only way would be to use the force or displacement method which is not easy and I don't have a civil engineering background.