Calculateur d'Espacement des Armatures — Formule

How to Calculate Rebar Spacing

Formula

Usable Span = Total Span - 2 × Edge Cover

Number of Bars = floor(Usable Span / Spacing) + 1

Actual Spacing = Usable Span / (Number of Spaces) × 12

Edge cover is the minimum distance from the edge of the concrete to the nearest rebar. Typical cover is 3 inches for cast-against-ground concrete and 1.5 inches for formed surfaces.

Exemple Résolu

Rebar across a 30 ft span at 12-inch spacing with 3-inch edge cover.

  1. Cover in feet = 3 / 12 = 0.25 ft
  2. Usable span = 30 - 2 × 0.25 = 29.5 ft
  3. Spacing in feet = 12 / 12 = 1.0 ft
  4. Number of bars = floor(29.5 / 1.0) + 1 = 30 bars
  5. Actual spacing = 29.5 / 29 × 12 = 12.21 inches