×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Reinforced concrete column

Reinforced concrete column

Reinforced concrete column

(OP)
Hi,

I am currently modelling a reinforced concrete column in ANSYS, and I am getting some strange results.

I am trying to see the effect of adding more steel links at the bottom of concrete columns, and finding the ultimate load of these columns.  To do this I have created several models varying the spacing of the steel links at the bottom of the column.  

I was expecting that the more steel I added to the column, the greater the ultimate load.  However, I have been finding that the more steel that I add, the earlier the column fails.  They tend to fail due to the solution not converging, not due to a large displacement for a small load, which leads me to believe that there is a convergence problem with the model, stopping the solution from progressing before the column reaches its ultimate load.

I am a relatively new ANSYS user, and so I am wondering whether I have missed some key information out of the model.  After many internet searches I have tried various things such as increasing/reducing the convergence criteria (reducing to 0.05% of the force and 0.5% of the displacement, and increasing to 0.5% of the force and 5% of the displacement) and increasing the equilibrium iterations (to 50) but to no avail - the solution still has trouble converging.  I have also tried playing around with the shear transfer coefficients of the concrete but again this hasn't helped.

I am modelling the concrete as SOLID65 elements and the reinforcement as LINK8 elements.  The nodes are shared so there is a perfect bond between the concrete and steel.  The base of the column is modelled as an elastic foundation of depth 1m (modelled using springs with stiffness EA/l), and the top of the column has been restrained in the horizontal plane, allowing displacement in the vertical direction only.  The column has been loaded with a pure axial load, applied as a surface pressure.

If anyone has any ideas as to what might be going on, I'd really appreciate some help!

Thanks,

Ross

 

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources