#3 Rebar (3/8 Inch Reinforcing Bar)
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 | #3 | Code Standard | ASTM A615 / A706 |
| Nominal Diameter (db) | 0.375 in | Metric Diameter | 9.53 mm |
| Cross-Sectional Area (Ab) | 0.11 in² | Metric Area | 71 mm² |
| Linear Weight | 0.376 lb/ft | Metric Mass | 0.56 kg/m |
| Nominal Perimeter | 1.178 in | Metric Perimeter | 29.9 mm |
| Minimum Clear Spacing | max(1.0″, 0.375″) | ACI Provision | ACI 318-19 §25.2.1 |
| Hook Type | Min. Inside Bend Pin | Extension Length (US) | Extension Length (SI) |
|---|---|---|---|
| 90° Standard Hook | 2.25″ (57 mm) | 4.5″ (12db) | 114 mm |
| 180° Standard Hook | 2.25″ (57 mm) | 2.5″ (max(4db, 2.5″)) | 64 mm |
Common Structural Applications
- ›Stirrups and ties for small beams and residential columns
- ›Temperature and shrinkage crack control in 4-inch concrete slabs
- ›Pool construction (gunite/shotcrete cages)
- ›Driveways, sidewalks, and residential footings
Standard hook requires 6db bend pin diameter (2-1/4 in). Highly workable by hand; rarely used as primary longitudinal bending reinforcement in structural beams.
#3 Rebar Spacing Table (As / Unit Width)
Area of longitudinal reinforcement provided for slabs, walls, and footing mats at given on-center spacings.
| 3″ o.c. | 4″ o.c. | 5″ o.c. | 6″ o.c. | 7″ o.c. | 8″ o.c. | 9″ o.c. | 10″ o.c. | 12″ o.c. | 14″ o.c. | 16″ o.c. | 18″ o.c. |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.440in²/ft | 0.330in²/ft | 0.264in²/ft | 0.220in²/ft | 0.189in²/ft | 0.165in²/ft | 0.147in²/ft | 0.132in²/ft | 0.110in²/ft | 0.094in²/ft | 0.083in²/ft | 0.073in²/ft |
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 |
|---|---|---|---|---|
| 3,000 psi | 16.4″(417 mm) | 21.4″(544 mm) | ACI 318-19 Table 25.4.2.3 | ld ≥ 12″ (300 mm) |
| 4,000 psi | 14.2″(361 mm) | 18.5″(470 mm) | ACI 318-19 Table 25.4.2.3 | ld ≥ 12″ (300 mm) |
| 5,000 psi | 12.7″(323 mm) | 16.5″(419 mm) | ACI 318-19 Table 25.4.2.3 | ld ≥ 12″ (300 mm) |
| 6,000 psi | 12″(305 mm) | 15.1″(384 mm) | ACI 318-19 Table 25.4.2.3 | ld ≥ 12″ (300 mm) |
Design Reinforcement with #3 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.