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Rigid Portal Frame Analysis

Rigid Portal Frame Analysis

RE: Rigid Portal Frame Analysis

In the formula k = (J2/J1) x (h/l), are J2 and J1 moments of inertia?
thank you for this. this really helps.

RE: Rigid Portal Frame Analysis

YES , J1 and J2 are moments of inerzia, as you say

RE: Rigid Portal Frame Analysis

There's a classic text called Kleinlogel, Rigid Frames Formulas, that gives manual solutions for all these portal frames. It's out of print, in German and old as the hills, but doggone handy. Someone might have a copy, or an illegal Xerox, or maybe it's in the library.
With all the computer power we have at our fingertips, it's still a good way to get a quick answer without making a model, and getting 50 pages of results.

RE: Rigid Portal Frame Analysis

hi JedClampett : yes, the file I sent is exactly excerpt from Kleinlogel (I am 66 years old, that's why. I did the PDF copy of that manual (in Italian), but probably for copyright reasons I am not allowed to shear

RE: Rigid Portal Frame Analysis

Hi RobyengIT and JedClampett! Thanks you for these info.. I'm making a spreadsheet software that calculates the structural size of the pipe supports. In the field of structural analysis, i still have a long way to go.. it's so nice that there are people like you around. Good health and more blessing for you both!!!

RE: Rigid Portal Frame Analysis

To solve the problem, moment distribution or rotations method should be use. I like rotations method better (exact method). It's really easy to solve for rotions in this problem because of the symmetry. Base of columns is zero rotation since it's fixed. Girder rotation is the same for both side, so there is only one unknown. Just have to write down fixed structure equations and you will find end moments easily. After you can solve for shear by making FBD. Hope it helps you down.

RE: Rigid Portal Frame Analysis

@robyengIT I tried to solve another portal frame (height = .7m, length = 2 m) with a load of 81kN at the center and with fixed supports legs. I followed the formula from Kleinlogel's pdf file but the results differs greatly when i tried to use Staad Pro software to calculate for the moments. I don't know if my handwritten solution is wrong but i have checked it multiple times to no avail. I attached the staad result in the link below.

RE: Rigid Portal Frame Analysis

@silenbam, can you please show me a simple draft of your method? thanks

RE: Rigid Portal Frame Analysis

I found another scheme : if the result is similar to the old one I sent to You, that means my schemes are correct (they were made by hand calculation and with all the standard formulas so that everybody could check and confirm and not by a computer programme done by an unknown John Doe)


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