Camparison of section capacity of concrete beam of rearrangement bars in beam

[ABA102]

Due to site condition the original arrangement of bars in concrete beam of one layer of 10T32 has been rearranged to 2 layers of 5T32. Is there a big impact in section capacity of the beam?

 

[JAE]

Yes - your depth to centroid of reinforcement has been reduced (smaller "d") so your flexural capacity, and shear capacity, is reduced.

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[Lomarandil]

The relative impact on this change will depend primarily on the overall depth of the beam. Any beam will be affected, but a 2' deep beam much more so than a 6' deep beam.

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The name is a long story -- just call me Lo.

 

[KootK]

I was planning to say just what Lomarandil did. Deeper beams tend to be quite insensitive to this kind of thing. Consider:

- I'm guessing this raises your reinforcement centroid about 1.5" (32 mm x (0.5 + 0.7)). Thus reducing your effective depth 1.5".

- For this change to affect your capacity by more than 5%, you're beam would need to be shallower than 30".

So, in KootK-land, we'd be letting this roll if the beam was 30" deep or more.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.