topic Re: Columns Calculation Note in Robot Structural Analysis Forum

Columns Calculation Note

faisal.aaouatif — Fri, 10 Feb 2012 22:38:19 GMT

Hi all ;

Im on RSA2011 - SP6 and i'm traying to work with Reinforment Columns module under EC8.

After exporting a column from RSA the remarks ive found are :

1. even if my live loads are defined on categorie "F" wich means a coefficient Psi-2 = 0.6 ; loadind table on the RC module shows 0.30 which not modifiable .... ( is there a way to correct it ? ) -- please See attachement

2.By examining the calculation Note ; i've found these remarks -- please See attachements ::

2.a Problem in calculation final excentricity

2.b Very big Moment magnificient coeffient

2.c the effective creep is greater the conventional one wich i think not correct.

2.d How does RSA determine the coefficient Js ? it is done after obtaining the reinforcement ?

Ive done calculation of this columns in comparaison on a excel sheet , an i obtained more reasonable values ie : Magnificient coeff = 2.834 ; effective creap = 0.226 ; [can send snap shot inf required].

I need to be figure out these pb -- have several columns to calculate

Thank you for help

Re: Columns Calculation Note

Artur.Kosakowski — Mon, 13 Feb 2012 13:56:30 GMT

Could you attach the rtd file with the column you attached the results for please?

Re: Columns Calculation Note

faisal.aaouatif — Tue, 14 Feb 2012 12:15:04 GMT

Good Morning/Evening Artur ;

The Rtd file Is sent by using a FTP site (Big model even after compressing ) given to me by private mail.

the calculation was done for the column 89 (Ground Floor).

when exporting from the model , at the column RC module the height of this column is equal to 5.7041m (even if the difference between upper level and bearing point is equal to 5.335 ? i dont know why , so i change it to 5.335m and the width of the beam to 0.70m

the coefficient of buckling i the direction y is equel to 4.424

the buckling analysis in the direction z is not important... at this stage.

So here is the summary of what i asked for and other points:

1.Coeff Phi2 change after export to Rc Column module ( See table of loads) [Priority 3]

2.is there a way to design the column exported with a steel resistance , the same as defined in job preference of the model [ in the model = 420MPa but in the RC Column design = B450C....]? ) [Priority 2]

3.How can we take seismic dispositions into consideration ( can't see any button for that ?) [Priority 2]

Other points .... :

4. Total excentricity : i think , its a final result , computed from final magnified moment and axial load.

5.the critical effort of buckling (243.99t) is lower than dimensionning one (362.28t) -- > i think that this should mentionned as a clear warning before continuig the analysis [Magnificient moment method has no meaning if there is such problem of stability ...] [Priority 1]

6.How RSA compute the effective coefficient of creep ( is it a average/min/max value of all combinations , the value for the unforable combination ) -- This coeff has a serious effect on other coeff. [Priority 1]

7.in the formula computing the rigdity ( EJ )shown at the calculation note ; it seems that the module Ecd is not divided by (1+coeff effective creep). - Is RSA consider that the column isolated even if its a part of hyperstatic structure ? (Reminder : See Eurocode2 - Art5.8.7.2.(4)) [Priority 1]

8.Is RSA computing the reinforcement by adopting the maximum moment at the column or by using an equivalent moment (0.60M1+0.40M2 as indicated on EC2-5.8.7.3 ? [Priority 1]

sorry for being too long

THANK YOU FOR YOUR EFFORTS

Re: Columns Calculation Note

Artur.Kosakowski — Wed, 15 Feb 2012 09:00:36 GMT

the calculation was done for the column 89 (Ground Floor).

5.335 (node to node; top node in the middle of the column height) + 0.5*0.7383 (height of the beam 1174) = 5.7041 (see the attached picture)

the coefficient of buckling i the direction y is equel to 4.424

Do you mean 4 times the column height (ky = 4.424) or just 4.424 m (Ly = 4.424 and ky =1)?

Re: Columns Calculation Note

faisal.aaouatif — Wed, 15 Feb 2012 11:17:24 GMT

Hi Artur;

i meant ky=4.424

Thanks

Re: Columns Calculation Note

Artur.Kosakowski — Wed, 15 Feb 2012 11:49:43 GMT

so i change it to 5.335m and the width of the beam to 0.70m

the coefficient of buckling i the direction y is equel to 4.424

the buckling analysis in the direction z is not important... at this stage.

1.Coeff Phi2 change after export to Rc Column module ( See table of loads) [Priority 3]

As you defined combinations in the model I assume you wanted to use them for the design as well so you can import them instead of simple load cases. This is what I’m going to do for checking next points.

Yes, you need to edit the reinforcement bar database and add bars with such steel grade.

http://forums.autodesk.com/t5/Autodesk-Robot-Structural/Provided-Real-Reinforcement-Bar-Diameter-List-How-to-add-new/m-p/3263604/highlight/true#M1845

Re: Columns Calculation Note

Artur.Kosakowski — Wed, 15 Feb 2012 11:54:02 GMT

3.How can we take seismic dispositions into consideration ( can't see any button for that ?) [Priority 2]

This functionality has been introduced in Robot 2012.

Re: Columns Calculation Note

Artur.Kosakowski — Wed, 15 Feb 2012 14:32:14 GMT

4. Total excentricity : i think , its a final result , computed from final magnified moment and axial load.

Correct.

This is not separately stated however in such case you should have both calculation error and information in the calculation note that the capacity of the column is too low. This request has been added to the wish list.

Calculated for each of the combination separately.

Re: Columns Calculation Note

Artur.Kosakowski — Mon, 31 Mar 2014 13:15:09 GMT

~~Correct. The request for implementation of Art5.8.7.2.(4)) is added to the wish list.~~

Implemented in Robot 2015.

8.Is RSA computing the reinforcement by adopting the maximum moment at the column or by using an equivalent moment (0.60M1+0.40M2 as indicated on EC2-5.8.7.3 ? [Priority 1]

The check is done in 3 locations: top and bottom for the values of bending moments from these locations and in the middle according to the above formula or real value of bending from the model if larger.

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.

Re: Columns Calculation Note

faisal.aaouatif — Thu, 23 Feb 2012 09:20:13 GMT

Good Morning Artur ;

having a problem to set the steel grade discussed above. see attachement

Another issue

when exporting a column RSA does not give me the hand to use my own combination , this why i'm using simple cases? How can i use mines ?

thanks

Re: Columns Calculation Note

faisal.aaouatif — Thu, 23 Feb 2012 10:58:53 GMT

Still having serious doubt about column calculation notes under EC2 with Rigidity method.

Please take a look to column 21 under RSA 2012 and RSA 2011 ( see documents attached ).

Dimension column on the model 800mm diameter. due to the real shape of the column , and after exporting this coulmn to RC module , ive edited its dimensions to a have rectangular equivalent column ( 690 x 870 mm²) with attention to My and Mz direction.

The buckling coefficient computed out of RSA are :

Direction x : Kx=2.19

Direction y : Ky=2.12

RSA2012 :

Coefficient Security < 0.00 !

Coeff effective crep < 0.00 !

Coeff Kc <0.00 !

the result is a very small value of euler critical load ( 10.72 t for a column of 690x870 mm ... )

RSA 2011:

Makes thing easier , the limit slenderness Lamda_lim = 343 ! , so there no need to use Rigidity method and the column is Ok !

Please , i you still have the model sent a week ago ; make a little verification by your side under 2012/2011 , and tell me is there anything to fix this problem

Regards

Re: Columns Calculation Note

Artur.Kosakowski — Fri, 24 Feb 2012 10:31:05 GMT

having a problem to set the steel grade discussed above. see attachement

Please make sure you first select the database you want to open and then you press the open button (see the attached picture)

when exporting a column RSA does not give me the hand to use my own combination , this why i'm using simple cases? How can i use mines ?

Please make sure you have manual combinations defined (they should be listed in the Analysis Type dialog.

Re: Columns Calculation Note

faisal.aaouatif — Fri, 24 Feb 2012 12:05:28 GMT

Ok for the first point ( it worked on RSA2011 but not in the RSA2012 ?? ).

manual combination are defined in the model and are listed in the analysis type dialog box but not enabled at export ( please see attachment ).

Re: Columns Calculation Note

Artur.Kosakowski — Fri, 24 Feb 2012 13:41:32 GMT

Ok for the first point ( it worked on RSA2011 but not in the RSA2012 ?? ).

Do you mean that you are still not able to open the rebar database using Robot 2012? Is it W7 64 bit?

manual combination are defined in the model and are listed in the analysis type dialog box but not enabled at export ( please see attachment ).

Open the combination table and switch to Values tab. Check what are the combination types ULS / SLS / ACC? What is the design code set in the RC Design module in this file?

Re: Columns Calculation Note

faisal.aaouatif — Tue, 28 Feb 2012 20:57:20 GMT

1 ) yes , still not be able to open it on RSA2012 ; im on xp 64 bit

the directory "C:\Documents and Settings\pc01\Application Data\Autodesk\Structural\Common Data\2011"under RSA2012 does not contain the file named "bar_EN 1992-1-1" listed in the same directory under RSA2011.

i tried to copy this file in the RSA2012 directory but i does not work. -- High Priority

Help appreciated

2) the combination types are set to ELU/ELS/ACC ( no difference between , CAR/FRE/QPR at the ELS Type) -

what is the use of the case nature ( see table attached ?)

Re: Columns Calculation Note

Artur.Kosakowski — Wed, 29 Feb 2012 07:55:17 GMT

1 ) yes , still not be able to open it on RSA2012 ; im on xp 64 bit

Please replace the original files in C:\Program Files\Common Files\Autodesk Shared\Structural\COM\2012\DBAccess with the attached ones. Please make copy of the original files before this replacement.

the directory "C:\Documents and Settings\pc01\Application Data\Autodesk\Structural\Common Data\2011"under RSA2012 does not contain the file named "bar_EN 1992-1-1" listed in the same directory under RSA2011.

I'm attaching this file from v.2012.

2) the combination types are set to ELU/ELS/ACC ( no difference between , CAR/FRE/QPR at the ELS Type) -

what is the use of the case nature ( see table attached ?)

It is not used. I'm afraid that I have to look at your file to investigate this point further. Could you send it please?

Re: Columns Calculation Note

Artur.Kosakowski — Wed, 29 Feb 2012 07:55:47 GMT

Re: Columns Calculation Note

faisal.aaouatif — Wed, 29 Feb 2012 08:53:36 GMT

i saved original files at desktop , replaced files in the directory "C:\Program Files (x86)\Common Files\Autodesk Shared\Structural\COM\2012\DBAccess" by ones attached ( DB-Part1 containes 6 dll ; DB Part2 contain 1 dll) ; [ the original DBacess contains 10files ...) ]

I added file attached " bar_EN 1992-1-1" to "C:\Documents and Settings\pc01\Application Data\Autodesk\Structural\Common Data\2012".

but still having the same problem ( button open not working )...

thanks for further help.

Re: Columns Calculation Note

Artur.Kosakowski — Wed, 29 Feb 2012 09:24:25 GMT

My understanding is that you replaced 10 files with 7 files I sent. Please restore the 3 files that are 'in addition' to the ones I sent. I uploaded only the files I wanted you to replace not all from this folder.

Re: Columns Calculation Note

faisal.aaouatif — Wed, 29 Feb 2012 15:34:40 GMT

this exatly what ive done. Replacing only the files uploaded.

but doesn't work