Measures · Reinforced concrete beam
Reinforced concrete beam pre-sizing FREE
Work out the depth and width of a reinforced concrete beam from its span. Below the result you find the formula and the standard.
Indicative pre-sizing. It does not replace a structural calculation signed by a licensed engineer. For seismic zones with agS (design ground acceleration) > 0.15g, long spans or use classes III/IV → talk to a structural engineer.
Pick a calculation from the list to start.
Formula, example and standard
h ≈ L/10 ÷ L/12 · b ≈ L/6 or 0.5÷0.7 · h
Example with the starting values (Span L: 5 m): Depth h ≈ 50 cm (rounded to multiples of 5 cm). Width b ≈ 83 cm.
- Recommended limit L ≤ 6 m for traditional cast-in-place reinforced concrete (RC).
- Always round h to multiples of 5 cm (for buildability).
- For L > 6 m: consider prestressed concrete or cut the span with intermediate supports.
Source: NTC 2018 §4.1 · Hoepli handbook · studiomadera.it
Indicative pre-sizing: it does not replace a calculation signed by a licensed engineer.
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