Development Length Calculator (CSA A23.3-19)
Development length of reinforcing bars per CSA A23.3-19: straight bars in tension, straight bars in compression, and standard hooks in tension. Pick the bar, concrete and steel strength, then tick the conditions that apply. The tool shows each modification factor with its clause and the resulting length.
CSA A23.3-19By Arun Kishore, P.Eng. Updated
Open calculatoropens in a new tabCode references
- CSA A23.3-19 Cl. 12.1.2: f'c limit of 64 MPa
- CSA A23.3-19 Cl. 12.2: tension development length, factors per Cl. 12.2.4
- CSA A23.3-19 Cl. 12.3: compression development length, factor per Cl. 12.3.3
- CSA A23.3-19 Cl. 12.5: standard hooks in tension, factors per Cl. 12.5.3
Inputs and outputs
| Inputs | Calculation type: tension, compression or hooked |
|---|---|
| Concrete strength f'c, 5 to 60 MPa | |
| Steel yield strength fy, 300 to 500 MPa | |
| Bar size, 10M to 55M | |
| Tension: minimum ties or stirrups, clear spacing, bar location, epoxy coating, concrete density | |
| Compression: spiral or tie confinement | |
| Hooks: 90 or 180 degree hook, side cover, tail cover, enclosing stirrups, epoxy coating, concrete density | |
| Outputs | Development length ld (tension or compression) or ldh (hooks), in mm |
| Each modification factor with its clause | |
| The minimum clear cover and spacing the tension result assumes |
Worked example
Worked example coming soon.
Limitations and assumptions
- Tension uses the simplified expressions with k1 k2 capped at 1.7. The result assumes clear cover of at least db and clear spacing of at least 1.4 db.
- Minimum lengths: 300 mm in tension, 200 mm in compression, and the larger of 150 mm and 8 db for hooks.
- The input slider stops at f'c = 60 MPa.
- No reduction for excess reinforcement.
These calculators are aids, not a substitute for engineering judgment. Check results independently and against the governing code edition before relying on them.