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Valued Mentor
tony.ridley
Posts: 652
Registered: ‎09-07-2011
Accepted Solution

RC column design

1402 Views, 7 Replies
01-30-2012 11:10 PM

Hi again Mr Robot

 

I have a question concerning RC column design.  

 

I've defined a building with a lot of columns, that are all the same section and concrete grade.  I want to rationalise the design and have all columns with the one reinforcement configuration.  I already know the bars I want, I don't need Robot to work it out for me or optimise it.  I just want to run all of my load combinations and verify that my reinforcement pattern works on all columns.  

 

Problem I'm having is that every time I run the RC calculator, it changes the bar pattern to something different.  The it takes a few goes to sort out one column.  Then I move to the next, it's very frustrating.  If I select multiple columns, alot of options become greyed out!!!  Why can't I apply the same reinforcement definition to multiple columns, or a chain of columns?

 

Please see attached PDF.  

 

Cheers,

Tony

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Product Support
Artur.Kosakowski
Posts: 4,849
Registered: ‎12-17-2010

Re: RC column design

01-31-2012 12:21 AM in reply to: tony.ridley

Tony,

 

Try to use the grouping option in RC Column Design module. Then you can open the predefined reinforcement pattern and apply it to the entire group at once and finally run verification against the loads imported from all the columns that are include in this group.

 

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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Valued Mentor
tony.ridley
Posts: 652
Registered: ‎09-07-2011

Re: RC column design

01-31-2012 04:00 AM in reply to: Artur.Kosakowski

Thanks Artur,

 

I was using "chain" previously, so it wouldn't let me do what i wanted.  

The way you have described it works well.  

 

Please tell me, what is the "chain" command normally used for?

 

Tony

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Product Support
Artur.Kosakowski
Posts: 4,849
Registered: ‎12-17-2010

Re: RC column design

01-31-2012 06:01 AM in reply to: tony.ridley

Please tell me, what is the "chain" command normally used for?

 

You can have automatic generation of dowel bars as well as additional information about the top column on the drawing of the bottom one.



Artur Kosakowski
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Contributor
rcadzior
Posts: 16
Registered: ‎01-20-2012

Re: RC column design

01-31-2012 12:41 PM in reply to: tony.ridley

Tony;

 

please refer to :

http://forums.autodesk.com/t5/Autodesk-Robot-Structural/Copying-items-in-RC-navigator/td-p/3301629

 

A similar problem was pointed out.

Robot has got "artificial intelligence " implemented instead of simple options :smileyhappy:

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Valued Mentor
tony.ridley
Posts: 652
Registered: ‎09-07-2011

Re: RC column design

01-31-2012 01:57 PM in reply to: rcadzior

Artur,

 

Thanks for that, yes I now understand the difference, however I still agree with rcadzior, there needs to be a way for the user to define a group manually.  

 

It's possible in steel design for the user to define their own groups.   I would imagine this type of grouping would be made available for RC/foundations too!

 

It's my birthday in March - Perhaps as a present you will provide AS3600 concrete code support and user defined grouping of RC members?   

 

Tony

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Valued Mentor
tony.ridley
Posts: 652
Registered: ‎09-07-2011

Re: RC column design

01-31-2012 02:32 PM in reply to: tony.ridley

Update!!!

 

Please refer attached PDF.  

 

I tryed using your method (of grouping by geometry) which to a degree works well (its reduced my number from 39 to 8) however;

 

1. I still get 8 groups of columns (I'm only interested in checking ONE reinforcement pattern!)

2. All columns are the same geometry - and essentially similar length - so why 8 groups?

3. What method does Robot use to group according to geometry?  

4. How come two columns esactly the same length and cross section are not grouped together (see pdf)?

5. What do I need to do to "trick" Robot into just making one single group?

 

Thanks,

Tony

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Product Support
Artur.Kosakowski
Posts: 4,849
Registered: ‎12-17-2010

Re: RC column design

02-01-2012 12:26 AM in reply to: tony.ridley

I do agree that we all want to have the options to work as we want them to work and in the way that is needed for the job that we are doing just now (and most likely in some different way for the next job we are about to do) :smileyhappy:

 

For the RC spread footing design module discussed earlier: please mind that this module in addition to finding the size of the foundation (length x width x height) is supposed to generate reinforcement of a pier and dowel bars to connect a spread footing with 'its' column. If the size of the column is different then the pier has to be different and arrangement of dowel bars has to be different as well not mentioning the fact that verification of punching strongly depends on the column (pier) size. This may be the reason why the groping of foundations may be not as one wants it to be. In case you (at the current design stage) don't care about piers or dowel bars add identical short columns at the bottom of the 'real' ones. They should not influence the results but should allow you to group the foundations and find both their right sizes and reinforcement of the bottom parts. Of course there is always something that could be improved but this is not always that 'easy' as it looks at the first sight :smileyhappy:

Perhaps it would be worth considering to add ignore column size check box to the import dialog to allow for a single group of foundations with different columns and the size of the common pier to be defined by the user afterwards (default size corresponding to the larges cross section of these columns). Would it be the acceptable option?

 

 

For the columns (I don't have the model so I cannot check if I'm right) most likely there are some beams at their top and/or bottom nodes. If these beams ( or slabs) are of different heights than the arrangement of stirrups cannot be the same (different groups created). In such case the arrangement of stirrups has to be different (see the attached picture) which prevents the same reinforcement generation for all columns. Perhaps you should approach this situation in a different way. As you know the sizes of rebars and their spacing you can try to create a named reinforcement pattern that can be used for reinforcement generation for selection of columns instead of column grouping.

 

Of course your original suggestion about applying saved typical reinforcement to many columns at one time has been noticed too.

 

 

 

 



Artur Kosakowski
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