Hi,
I am investigating the behaviour of a 3D structure of RC frames with masonry infills with a Pushover analysis. The frame elements I'm using are FB elements. I have No. of Nodes: 153, No. of Elements: 333.
My questions are:
1. 3D PUSHOVER and MASS?
I have tried 2 different ways of applying the incremental loads. First, I put a null value on weight per volume for each element (frames and infills) and I concentrated the whole mass at the mass center on each floor level. Then I put the incremental loads on each mass. The second way, I spread the mass of the floor on each node with freight areas and leave the program to account the mass of the other elements. Here, I put the incremental loads on the one sight of the structure on each element node (as the wizard also shows, when choosing a 3D pushover). I am asking which way is right, because I have a doubt whether the FB elements work with no weight per volume. Furthermore, the modal analysis does not work using the first way and the Capacity curves were totally different!
2. FB ELEMENTS?
In the help it's said that FB elements don't have problems with the convergence. Even though, I change the values of element loop convergence tolerance (to 0,0001) and element loop maximum iterations (to 1000) the analysis stops with unabling to apply the whole load, because of some following messages "fbd_ite". Why?
The iterative strategy I am chosing is:
max. No of iterations: 300
No of stiffness updates: 150
divergence iterations: 250
max. tolerance: 1e10
I have also change the displacement criteria:
displacement tolerance: 0,0001
rotation tolerance: 1e-4
Hope to receive an answer as soon as possible!
Best regards
Pushover on 3D structure
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seismosoft
- Posts: 1272
- Joined: 06 Jul 2007, 04:55
Re: Pushover on 3D structure
Mae,
1) have you tried searching this Forum for "3D Pushover"?..
2a) we are not sure we understand what you mean with "in the Help it's said that FB elements don't have problems with convergence", since this obviously is not true, and the Help System cannot feature such a statement (if it does, then let us know, and we will correct it).
2b) again you should search this Forum for expressions such as "convergence problems" or similar.
Seismosoft Support
1) have you tried searching this Forum for "3D Pushover"?..
2a) we are not sure we understand what you mean with "in the Help it's said that FB elements don't have problems with convergence", since this obviously is not true, and the Help System cannot feature such a statement (if it does, then let us know, and we will correct it).
2b) again you should search this Forum for expressions such as "convergence problems" or similar.
Seismosoft Support