Time dependent Conrete properties

[mustafahesenow]

Hi All,

As we know that concrete properties will change during the time.

Its related to creep and shrinkage which will affect the modulus of elasticity during this the considered time which is will cause significant changes for high rise building when we check the column shortening.

Is there a way to consider this in times of analysis of concrete structure in Robot.

[Artur.Kosakowski]

Hi Mustafa,

No there is not such possibility. Such time effect are not considered.

For shrinkage you may consider the use of temperature load (uniform cooling TX) if such approximation is acceptable.

[alfredmx]

Hello mustafahesenow,

For calculating redistribution of internal stresses (mainly due to creep) in prestressed concrete bridges we have successfully used EN1992-2 Annex KK formula.

Sf=So+(Sc-So)f

in which

Sf=final stressed

So=stresses from construction stages

Sc=stresses assuming the structure is built in one and all permanent loads are applied at the same time

f=factor that depends on final creep coefficient, loading time and aging factor

Results using above formula and those obtained by software that considers explicitly time-dependent concrete effects are in good agreement. The process however becomes complicated because unfortunately RSA phases is very limited, so you have to extract results from individual models and do staged analysis externally. Never tried this approximation in building construction as this effects are usually not considered.

Regards,

[mustafahesenow]

Hi @alfredmx

I had checked this formula for high rise building and it is giving wrong results.

Any way thank you so much for help.

[mustafahesenow]

Hi @Artur.Kosakowski

These changes in concrete is related to to time and concrete age. 

Material non-linearity was one of the most big problems to RSA.

I really dont know why Autodesk doesnt develop RSA in a good direction.

Since 2010 the only changes on RSA aside analysis is DAM method and wind simulation where Robobat before had every year many new things .

[Artur.Kosakowski]

Hi @mustafahesenow

Thank you for your comments - I have forwarded them 'higher'.

I'd love to see many new options in every new released version too

[mustafahesenow]

Hi @Artur.Kosakowski

Most of the softwares which was nothing compare to Robot having this type of analysis and since long time 

Take a look on (Etabs , Midas , Sap , Staad ,,,,,, etc )

Check the Ideas forum  a lot of Ideas requested and many versions of Robot having very minor changes I really hope to know why like that .

[Artur.Kosakowski]

Hi @mustafahesenow

First of all I'd like to thank you for posting your very valuable ideas and your tremendous participation on this forum however I may not be the best person to answer this type of questions. I'm the first one to vote for them and I'd love to see them being implemented but as a part of the Autodesk Tech Support Team I'm not in the position to make this happen. I hope the development team will consider them in the future.

[mustafahesenow]

Hi @Artur.Kosakowski

Thank you so much my friend.And I really understand and appreciate all what you said. 

But in the other hand.This is our software and its our community which is handled by Autodesk .

You may cant answer our questions but you may transfer this talk to Autodesk and then tell us  what their plan. Or If couldn't we need to know 

how can we talk to Autodesk and discuss with them this issue .