Steel Rebar Unit Weight Formula
W_{unit} = frac{D^2}{162.198} text{ kg/m} = frac{D^2}{533.33} text{ lb/ft}; quad W_{total} = W_{unit} times L_{cut} times N_{bars}
Engineering Specifications & Method of Calculation
Reinforcing steel bars (rebar) are estimated by linear cut lengths and cross-sectional unit mass using standard ASTM/IS/BS weight formulas.
Calculating Rebar Cut Length & Tonnage
The standard formula D²/162 derived from steel density (7850 kg/m³) provides unit weight per meter for any bar diameter D in millimeters. Multiply unit weight by total cut length including hooks, bends, and standard lap lengths (40D to 50D).
Frequently Asked Questions
How is D²/162 derived?
It is derived from circular steel volume (π D² / 4) multiplied by steel density 7850 kg/m³ divided by 1,000,000 to convert square millimeters to meters.
What is the standard commercial length of a rebar?
Stock rebar is manufactured and delivered in 12-meter (40-foot) standard lengths.