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PostPosted: Fri Feb 03, 2017 11:41 pm 

Joined: Fri Feb 03, 2017 10:39 pm
Posts: 3
Location: Ljubljana, Slovenia
Dear fellow engineers/Sofistik AG staff, I need assistance with a problem, that 's been bugging me for a while.

In my work, earthquake analysis is the basis for structure design, I am trying to perform it using Response Spectrum Analysis (RSA) and with input through CADINP (Teddy modules in SSD).

I defined Teddy modules for geometry , static loads and superpositioning from scratch, and converted the predefined tasks 'Earthquake' and 'Linear analysis' to 'User defined task' so I was able to modify them more effectively.

What I want to get for result (displacements, reactions, beam internal forces), is to calculate all the static and dynamic load cases and combine them using 'Maxima' user task.

Finally, let me state the problem:
The combination results got internal beam forces (My, N, Vz...) combined just fine, but quantities in nodes are missing the values from 'earthquake' load case: values (displacements and reactions) are calculated separately for static and dynamic cases just fine, but combination is showing just the parts from static cases and missing dynamic case.

'Role' model for my work was tutorial example 'EARTHQUAKE ANALYSIS WITH RSA' from Sofistik, comparing it with my project file, i didn't find the mistakes.

In the attachment you will find a simple Sofistik project file with RC column, following my usual procedure. Can you please check it, especially the parts defining combination of results and earthquake analysis ('Superposition' task, 'Earthquake' task)?

Can you also check the code, written beneath? It is used for definition of the response spectra (Eurocode 8, EC-1 type) and I don't understand the idea of defining both: SA, SB spectral values on one side and AG value on the other side. I get a 100 % fit of results by setting AG value to 1.0 (m/s2) and setting SA and SB to values from the design spectra. I found that MOD (behaviour factor) doesn't affect the results!?

Here 's the code:
+PROG SOFILOAD urs:18.3 $ Definition Response Spectra
HEAD Definition Response Spectra
LC 990 TYPE NONE $ 'X' earthquake
RESP TYPE EC-1 CLAS B MOD 1.2 SA 1.5 SB 2.81 SMIN 0.200 TB 0.150 TC 0.500 TD 2.000 TE 0.0 K1 1.000 K2 2.000 AG 1.0 AH 1

It 's not very enjoyable having these trivial problems and the solution is probably just changing a word or line in the whole Teddy code.

I thank you all for answers


Uros G.

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PostPosted: Sat Feb 04, 2017 12:10 am 

Joined: Fri Feb 03, 2017 10:39 pm
Posts: 3
Location: Ljubljana, Slovenia
To make the last message shorter:

I want to understand, why results from combinations (Maxima) are OK for beam elements (internal forces) and not good for nodes (displacements and reactions are missing the earthquake analysis part).

Best regards

Uros G.

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