• Registered: 2010-03-09
  • Posts: 26

Topic: Concrete cover / distance of bottom & top reinforcement frm concrete

Hello sir. I am using atena 2D demo version. I am analyzing reinforced concrete beams. I have problems analyzing the concrete cover (distance of the top/bottom reinforcement away from the concrete). Is the difference going to affect the results? In my first analysis, I have used concrete cover of 25mm and I've obtained the results. In my second analysis, I have changed the concrete cover to be 10mm. From the results, I found that the ultimate load is higher than the 25mm concrete cover results. Is it possible? However, in  my experimental work with concrete cover of 10mm, the reinforced concrete beams failed faster as compared to the theoretical results. How can i solve this problem?

Thank you very much.

Quote Post 1

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: Concrete cover / distance of bottom & top reinforcement frm concrete

Clearly, everything else neglected, positioning the reinforcement closer to the surface (=further away from the beam axis), increases the effect of the reinforcement and by that the bending resistance.

However, other, frequently stronger, effects can have influence in the opposite direction - among others: corrosion, bond, aggregate size.

To capture these effects in an analysis, one needs a pore flow + chemical analysis for corrosion (or at least some estimate based on the cover depth + type of environment). The rest may be captured by defining the reinforcement bond parameters corresponding to the cover + aggregate size.

In ATENA, with a fine enough mesh for the concrete (usually, mesh size = aggregate size is about the smallest which makes sense), you should be able to get at least a part of the effects even without manually calculating the bond strength reduction.

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Quote Post 2