Glossary: Nominal Mass
Nominal weight (nominal mass) means the standardized unit weight of a reinforcing steel bar (rebar) or structural metal member per unit length or surface area, as established by regulatory engineering codes for material scheduling, billing, and structural design calculations, ignoring minor manufacturing tolerances.
Rebar Nominal Weight Formula Derivation
In reinforcing steel bars, the nominal mass is used to translate linear dimensions (feet or meters) into shipping weights and billing invoices. Manufacturers roll rebar with ribs and deformities, causing minor weight variances, but calculations must rely on standardized nominal tables:
- US Standard (lb/ft): Governed by ASTM A615, nominal unit weights range from **0.376 lb/ft** (#3 bar) to **13.60 lb/ft** (#18 bar).
- Metric / ISO 6935-2 Standard (kg/m): Computed by the physics formula:
Mass (kg/m) = 0.006165 × d²
Where d is the nominal diameter in millimeters.