Modeling reinforced concrete column

[NessaArya]

Hi everyone,

I am a master student working on my master thesis using ABAQUS. I am modeling an experiment, but the problem is that my results from ABAQUS do not agree with the experimental results. Can you help me an check if I have done any mistakes?

The model is a slender square concrete column 150x150 mm and 1300mm long.
Longitudinal reinforcement: 550MPa, diamater 8mm
Lateral reinforcement: yield strength 630MPa, diamater 6.5mm, spacing 10.5mm
Mean compressive strength of concrete: 34.32 MPa
Eccentricities of applied load: ex=50mm ey=50mm
Load: 1kN/s
Pinned conditions at both sides

I use concrete plasticity damage model. For defining the load I use deformation control with a prescribed deformation 0.010mm.

I have attached my input file.

Thank you for your help!
// Nessa

 

[Mustaine3]

It seems like your unit system uses m as length, so you apply a velocity of -0.01m/s for 20s. Is that correct?

And you use Ideal Plasticity for your reinforcement. Make sure you never reach the yield stress.

 

[NessaArya]

Yes You are right. The unit is meter.

So there are no other mistakes in the model? I still don't get correct results like the experiment.

 

[Mustaine3]

Is buckling happening in reality?

Maybe you get a big inetia when the velocity is applied with the full value at the beginning of the analysis. Create a smooth step amplitude and apply a displacement with that amplitude, to slowly accelerate the moving end.

 

[NessaArya]

Thanks Mustaine3!

I had problem with the units and I fixed it. I have also changed the Amplitude to Smooth Step and did other changes to the model as well. But still I don't get correct result. In the experiment the maximum load reached is 900 kN. However I only reach 90 kN before failure.

I have attached my latest input file.

What is the reason I reach failure so early?

Thanks!
Nessa