ᐅ Structural engineer: 2 layers of 8mm reinforcement bars or 1 layer of 16mm reinforcement bar

Created on: 29 Mar 2017 09:53
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pixelprof
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pixelprof
29 Mar 2017 09:53
How does the tensile strength of reinforced concrete (e.g., in horizontal beams) compare when using 2 x 8mm (5/16 inch) reinforcing bars versus 1 x 16mm (5/8 inch)?
Or also 2 x 6mm (1/4 inch) compared to 1 x 12mm (1/2 inch)? (Assuming identical components and the same steel grade.)
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ypg
29 Mar 2017 09:55
Wrong forum? This is for home builders 🙂

Best regards, Yvonne
andimann29 Mar 2017 10:48
Hello,
pixelprof schrieb:
if I use 2 x 8mm reinforcement bars compared to 1 x 16mm.

Simply put:
just calculate the cross-sectional areas, that should answer your question:

Cross-sectional area of the 8mm reinforcement: 50 mm² (0.08 in²) (4*4*pi)
Cross-sectional area of the 16mm reinforcement: 200 mm² (0.31 in²) (8*8*pi)

The tensile strength of reinforced concrete is largely determined by the reinforcement. So you can’t simply replace one 16mm bar with two 8mm bars; you would actually need around four 8mm bars.

It’s probably not that straightforward in reality, as there are other factors involved, such as the distribution and positioning of the reinforcement.

Best regards,

Andreas