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Wioletta_F
Posts: 49
Registered: ‎08-24-2012
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Partial Fixity

377 Views, 16 Replies
10-24-2013 08:02 AM

Hi,

I've got a question with regard to partial fixity of RC columns. My problem is that I'm trying to analyse an exisitng concrete structure that deflected 'a lot'. I've managed to model the whole structure and have run calculations in 2 options: fully fixed columns - option 1 and pinned - option 2. The long term deflection results from Robot indicate that I should be considering a partial fixity of columns (I should mention that I've got a survey report with deflection that occured in 'real life' ). Could you help me to define 'partial fixity' of columns? I tried defining a new release type by going to new release/ elastic/ partial stiffness coefficient but no matter what value i put when verifying the model I get an error saying 'to excesive release  at the bar'. Please help.

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Artur.Kosakowski
Posts: 4,750
Registered: ‎12-17-2010

Re: Partial Fixity

10-24-2013 11:20 PM in reply to: Wioletta_F

Please check http://forums.autodesk.com/t5/Robot-Structural-Analysis/Steel-design/m-p/3573540

 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.



Artur Kosakowski
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Active Contributor
Wioletta_F
Posts: 49
Registered: ‎08-24-2012

Re: Partial Fixity

10-25-2013 02:42 AM in reply to: Artur.Kosakowski

Thanks Artur.

This works better now. Unfortunately during the deflection analysis I get an error now: Incoherent results for panel 2, although I did not change anything appart from fixity and other panles are ok (no error message). The error is fallowed by 'execution problem 2520' when I ignored.

 

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Artur.Kosakowski
Posts: 4,750
Registered: ‎12-17-2010

Re: Partial Fixity

10-25-2013 02:51 AM in reply to: Wioletta_F

Am I correct that you selected the stiffness update method? What is the analysis type - linear static or nonlinear ? Do you have enough free space on the disk? Do you run the file from the local derive or a network location? Is it the same for the multi-threaded solver?



Artur Kosakowski
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Active Contributor
Wioletta_F
Posts: 49
Registered: ‎08-24-2012

Re: Partial Fixity

10-25-2013 03:09 AM in reply to: Artur.Kosakowski

0. Linear analysis

1. Equivalent Stiffness (Elastic) - works, I do get results - although the Error comes up - see the attached pdf

2. Stiffness update stops the analysis and Execution problem comes up - see the pdf

3. Changed the solver - same

4. I think I've got enogh space on the disk

5. I'm using a network license of Robot and running the file from server.

 

 

 

 

 

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Artur.Kosakowski
Posts: 4,750
Registered: ‎12-17-2010

Re: Partial Fixity

10-25-2013 03:18 AM in reply to: Wioletta_F

Try to save the file on a local drive change the reinforcement calculation method from analytical to Wood and Armer - any change? 

 



Artur Kosakowski
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Active Contributor
Wioletta_F
Posts: 49
Registered: ‎08-24-2012

Re: Partial Fixity

10-25-2013 04:15 AM in reply to: Artur.Kosakowski

Hi

I saved my file on a local drive. First time I run analysis all went ok, after that either the 'incoherent data' or 'execution problems' occur (I tried couple of times).

 

btw. The values of stiffeness coefficients range between: 0.0 (a released direction) and 1.0 (no release). So if i type in 0.1 does it mean 90% of fixity or 10% of fixity. Thanks.

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Artur.Kosakowski
Posts: 4,750
Registered: ‎12-17-2010

Re: Partial Fixity

10-25-2013 06:16 AM in reply to: Wioletta_F

I saved my file on a local drive. First time I run analysis all went ok, after that either the 'incoherent data' or 'execution problems' occur (I tried couple of times).

 

Can you calculate (again) deflections after closing Robot and opening it again?

 

btw. The values of stiffeness coefficients range between: 0.0 (a released direction) and 1.0 (no release). So if i type in 0.1 does it mean 90% of fixity or 10% of fixity. Thanks.

 

10% but you can easily check that making a test on a single bar model with fixed supports at both ends :smileyhappy:

 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

 



Artur Kosakowski
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Active Contributor
Wioletta_F
Posts: 49
Registered: ‎08-24-2012

Re: Partial Fixity

10-25-2013 06:33 AM in reply to: Artur.Kosakowski

 

 

I even shut the computer down and that did not help much.

 

 

 

I asked about the fixity because I did as you said - changed values couple of times and the deflection results went up and down not exactly as I expected them to go :smileyhappy:.

 

 

 

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Artur.Kosakowski
Posts: 4,750
Registered: ‎12-17-2010

Re: Partial Fixity

10-25-2013 06:47 AM in reply to: Wioletta_F

Send me the rtd file and indicate the slab to run deflection verification for please. Thank you.



Artur Kosakowski
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