Topic: Multiple Bond Models for 1D Reinforcement Connected in Series

Hello,

My name is Jeff, and I am trying to model bond-slip for smooth reinforcing bars. I would like to model a straight bar segment connected to a 180-degree hooked anchor (i.e. two bond models for the same reinforcing bar). Research by Fabbrocino et al. (2004 and 2005) have shown both to be significant in older RC structures.

I’ve read some previous posts related to this subject. One post from 2013 by Francesco who was attempting to model two bars in series but found that the 1D truss elements were not directly connected but were connected only through a transfer of forces with the surrounding concrete elements.

Another post by njoukhadar in 2019 appeared to be attempting something similar, but the final solution wasn’t clear. The user may have sent in his/her model and received additional help, but this was not posted in the forum.

I have attempted to model two 1D reinforcement bars in series: (1) having low bond quality and (2) with the bond properties associated with a hooked anchor. The force transfer and damage to the surrounding concrete suggests that the bars are not attached together. I was wondering if there is a solution for this such that I can connect the two bars in series with different bond models? Your help would be greatly appreciated.

Kind Regards,
Jeff

Re: Multiple Bond Models for 1D Reinforcement Connected in Series

Dear Jeff,
I assume you have already read ATENA Troubleshooting, 2.2.12.3 Unbonded segments.

I guess the simple approximation with perfectly bonded hook as 1 bar + the rest as a 2nd bar with the corresponding bond law (with "no slip" at the end connected to the hook part) has also shown as not good enough?

You can send us some sketches + description (Troubleshooting, 2.1.1) such that we can try to find a good way of modelling for you.

Regards.

Re: Multiple Bond Models for 1D Reinforcement Connected in Series

Hi Jeff,

Which program do you use? (Atena 2D, 3D, Science). I have just tried one bar of 2 segments, one with perfect connections, another with bond and found there is no problem. You can see it on the linked pictures:
https://drive.google.com/open?id=19ZQHC … y99y_fKmlr