Kostenloser Bewehrungsstahl-Rechner
Berechnen Sie die benötigte Bewehrungsstahlmenge für Betonflächen und -fundamente.
On center spacing, typically 12" to 24"
Standard rebar comes in 20 ft lengths
Total Bars (both directions)
28
Total Bars (both directions) vs Slab Length
Formel
## How to Calculate Rebar Needed ### Formula **Bars Along Length = floor(Width / Spacing) + 1** **Bars Along Width = floor(Length / Spacing) + 1** Rebar is laid in a grid pattern (both directions). Standard rebar comes in 20-foot lengths. Overlap joints should be at least 24 bar diameters (about 18 inches for #4 rebar). Common sizes are #3 (3/8"), #4 (1/2"), and #5 (5/8").
Lösungsbeispiel
A 20×20 ft slab with rebar on 18-inch centers, using 20 ft rebar.
- 01Spacing in feet = 18 / 12 = 1.5 ft
- 02Bars along length = floor(20 / 1.5) + 1 = 14 bars (each 20 ft long)
- 03Bars along width = floor(20 / 1.5) + 1 = 14 bars (each 20 ft long)
- 04Total bars = 14 + 14 = 28 bars
- 05Total linear feet = 14 × 20 + 14 × 20 = 560 lin ft
- 06Rebar sticks = 560 / 20 = 28 sticks
Häufig Gestellte Fragen
What size rebar for a 4-inch slab?
#3 (3/8 inch) or #4 (1/2 inch) rebar on 18-24 inch centers is standard for 4-inch residential slabs. Some codes allow welded wire mesh (6×6 W1.4/W1.4) instead.
How much do I overlap rebar joints?
The standard splice length is 24 bar diameters minimum. For #4 rebar (1/2 inch), that is 12 inches. For #5 rebar (5/8 inch), that is 15 inches. Many specs call for 18 inches minimum.
Where should rebar be placed in a slab?
Place rebar at 1/3 of the slab thickness from the bottom, supported on chairs (rebar supports). For a 4-inch slab, the rebar should be about 1.5 inches from the bottom.
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