Bar Weight
W = 0.00616 × d² kg/mLoading page content...
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Calculate steel reinforcement quantities including bar weight, total length, and material breakdown. Supports global standards and bar spacing calculations. Free construction calculator.
Range: 3-10% (typical 3-10%)
Optional: Calculate from Spacing
Center-to-center spacing
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Structural & RC Design
Calculate rebar weight, quantity, spacing, cover, development length, and cost for slabs, beams, and columns per IS 456 and ACI 318.
Steel Density
7850 kg/m³
Cover (IS 456)
25-75 mm
Fe500 Yield
500 MPa
Rebar Weight
0.00616 × d² kg/m
Reviewed by: CalculatorApp Structural Engineering Team
Steel reinforcement converts plain concrete into reinforced concrete (RC) — a composite material that resists both compressive and tensile forces. Deformed bars (rebar) bond mechanically to concrete through surface ribs, preventing slip as stresses develop under loads. Correct rebar sizing, spacing, cover depth, and development length are critical to structural safety and durability in slabs, beams, columns, and foundations.
Bar Weight
W = 0.00616 × d² kg/mBar Area
A = πd²/4 mm²Development Length
Ld = (φ × σ_s)/(4 × τ_bd)Spacing Check
S ≤ min(3d, 300 mm)| IS Bar Size (mm) | Cross-Sectional Area (mm²) | Weight (kg/m) |
|---|---|---|
| 8 mm | 50.3 | 0.395 |
| 12 mm | 113.1 | 0.888 |
| 16 mm | 201.1 | 1.578 |
| 20 mm | 314.2 | 2.467 |
1849: Joseph-Louis Lambot builds the first reinforced concrete boat in France, patented in 1855.
1867: Joseph Monier patents reinforced concrete flower pots, tubs, and bridges, pioneering modern RC.
1880s: Ernest Ransome and François Hennebique develop practical RC framing systems for buildings.
1906: San Francisco earthquake destroys unreinforced buildings; RC structures survive, driving global adoption.
1956: IS 456 (India) first published; ACI 318 (USA) governs RC design — both continuously updated.
Modern era: High-strength Fe500D/Fe550D bars and fiber-reinforced polymer (FRP) rebar extend RC into harsh environments.
Indian Standard for plain and reinforced concrete design.
American Concrete Institute structural concrete building code.
OSHA requirements for safe rebar handling on construction sites.
ASTM A615/A706 standards for deformed steel bars.
Myth: More rebar always means a stronger structure.
Fact: Over-reinforcement can cause brittle concrete crushing failure before steel yields. Codes specify maximum reinforcement ratios.
Myth: Cover of any depth is acceptable.
Fact: Too little cover causes corrosion; too much wastes concrete and reduces section efficiency. Code-minimum cover is mandatory.
Myth: All rebar grades are interchangeable.
Fact: Fe415, Fe500, and Fe500D have different yield strengths and ductility. Grade selection must match the design load and seismic requirements.
Myth: Lap splices can be placed anywhere.
Fact: Codes restrict laps to low-stress zones and prohibit them at points of maximum moment where full bar capacity is needed.
Concrete is strong in compression but weak in tension. Steel rebar absorbs tensile stresses, preventing cracking and catastrophic failure in beams, slabs, and columns.
Cover is the minimum thickness of concrete from the rebar surface to the nearest face. It protects steel from corrosion; IS 456 specifies 25-75 mm depending on exposure class.
Development length (Ld) is the minimum bar length needed to transfer stress between steel and concrete. Ld = (φ × σ_s) / (4 × τ_bd), per IS 456.
For flexural members per IS 456: As_min / bd = 0.85/fy. Per ACI 318: ρ_min = max(3√f'c/fy, 200/fy) in psi units.
IS 1786 bars: 6, 8, 10, 12, 16, 20, 25, 32 mm. For slabs typically 8-12 mm; for beams/columns 16-25 mm.
#3 (10 mm), #4 (13 mm), #5 (16 mm), #6 (19 mm), #7 (22 mm), #8 (25 mm) — numbers indicate bar diameter in 1/8-inch increments.
Steel density = 7850 kg/m³ (7.85 g/cm³). Weight of rebar per meter = 0.00616 × d² kg/m where d is diameter in mm.
Per IS 456 for beams: stirrup spacing ≤ least of 0.75d, 300 mm, or 48 times stirrup bar diameter. ACI 318 has similar limits.
Where two bars overlap to transfer force, a lap splice length is typically 40-60 times the bar diameter (per IS 456 and ACI 318).
HYSD (Fe415/Fe500 per IS 1786) are high-yield deformed bars used in modern RC; mild steel (Fe250) is now rarely used.
Fe500 designates high-yield deformed steel with 500 MPa minimum yield strength per IS 1786; Fe415 has 415 MPa yield strength.
Bent-up bars are inclined 45° near supports in beams to carry diagonal tension (shear). They supplement vertical stirrups.
Combine steel reinforcement with concrete, beam deflection, and staircase calculators for complete reinforced concrete design.
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