20 mm Rebar (European Standard Metric)
Authoritative dimensional properties, unit weight, cross-sectional area, spacing tables, standard hook geometries, and ACI 318-19 tension development length for structural concrete design.
| Bar Designation | Ø20 | Code Standard | EN 10080 / Eurocode 2 |
| Nominal Diameter (db) | 0.787 in | Metric Diameter | 20 mm |
| Cross-Sectional Area (Ab) | 0.487 in² | Metric Area | 314.2 mm² |
| Linear Weight | 1.657 lb/ft | Metric Mass | 2.466 kg/m |
| Nominal Perimeter | 2.474 in | Metric Perimeter | 62.8 mm |
| Minimum Clear Spacing | max(1.0″, 0.787″) | ACI Provision | ACI 318-19 §25.2.1 |
| Hook Type | Min. Inside Bend Pin | Extension Length (US) | Extension Length (SI) |
|---|---|---|---|
| 90° Standard Hook | 3.15″ (80 mm) | 9.4″ (12db) | 240 mm |
| 180° Standard Hook | 3.15″ (80 mm) | 3.1″ (max(4db, 2.5″)) | 80 mm |
Common Structural Applications
- ›Heavy commercial beams, moment frames, and high-load foundation footings
- ›Primary vertical reinforcement in 300x300 mm and 400x400 mm building columns
Area is 314 mm²; weighs 2.47 kg/m. Mandrel diameter increases to 7db = 140 mm if bars are bent in shear reinforcement or anchorages.
Ø20 Rebar Spacing Table (As / Unit Width)
Area of longitudinal reinforcement provided for slabs, walls, and footing mats at given on-center spacings.
| 75 mm o.c. | 100 mm o.c. | 125 mm o.c. | 150 mm o.c. | 175 mm o.c. | 200 mm o.c. | 250 mm o.c. | 300 mm o.c. | 400 mm o.c. |
|---|---|---|---|---|---|---|---|---|
| 4189mm²/m | 3142mm²/m | 2514mm²/m | 2095mm²/m | 1795mm²/m | 1571mm²/m | 1257mm²/m | 1047mm²/m | 786mm²/m |
ACI 318-19 Tension Development Length (ld)
Calculated using ACI 318-19 Section 25.4.2.3 simplified method for Grade 60 (420 MPa) deformed bars in normal-weight concrete with clear spacing ≥ db and clear cover ≥ db.
| Concrete Strength (f'c) | Bottom Bars (ld) [ψt = 1.0] | Top Bars (ld) [ψt = 1.3] | Governing Provision | Minimum Limit |
|---|---|---|---|---|
| 21 MPa (~3045 psi) | 1078 mm | 1402 mm | CSA A23.3 / ACI 318M | ld ≥ 300 mm |
| 28 MPa (~4060 psi) | 934 mm | 1214 mm | CSA A23.3 / ACI 318M | ld ≥ 300 mm |
| 35 MPa (~5075 psi) | 835 mm | 1086 mm | CSA A23.3 / ACI 318M | ld ≥ 300 mm |
| 42 MPa (~6090 psi) | 762 mm | 991 mm | CSA A23.3 / ACI 318M | ld ≥ 300 mm |
Design Reinforcement with Ø20 in AXIS
Run instant ACI 318-19 beam flexure, shear stirrup spacing, column P-M interaction, and development length checks with full KaTeX step-by-step audit logs.