Project Information
Design Parameters
Modification Factors
Geometry & Confinement
Advanced Options
Hook & Head Options
Results Summary
Tension Development
ℓd — straight bar
—in
§25.4.2
Tension Splice
ℓs — Class B (1.3ℓd)
—in
§25.5.2
Compression Dev.
ℓdc — straight bar
—in
§25.4.9
Compression Splice
ℓsc — lap splice
—in
§25.5.5
Hooked Bar Dev.
ℓdh — standard hook
—in
§25.4.3
Headed Bar Dev.
ℓdh — headed bar
—in
§25.4.4
Section Diagram
Modification Factor Reference
ψt — top cast (≥12")
1.3
ψe — epoxy (cover < 3db or spacing < 6db)
1.5
ψe — epoxy (other)
1.2
ψs — #6 and smaller
0.8
ψg — fy = 100 ksi
1.15
ψg — fy = 120 ksi
1.30
λ — sand-lightweight
0.85
λ — all-lightweight
0.75
ψr — hook confined
0.75
ψt · ψe product limit
≤ 1.7
Per ACI 318-19 Tables 25.4.2.4, 25.4.3.2 & 25.4.4.2
Complete Calculation Package
All equations rendered in LaTeX with substituted values
References & Notes
ACI 318 Code References
- §25.4.2 Development of deformed bars in tension
- Eq. 25.4.2.2a General development length equation
- Table 25.4.2.4 Modification factors for tension
- §25.4.3 Development of hooked bars in tension
- §25.4.4 Development of headed bars in tension
- §25.4.9 Development of deformed bars in compression
- §25.5.2 Tension lap splices (Class A / Class B)
- §25.5.5 Compression lap splices
Calculation Notes
- • Tension splice defaults to Class B (1.3 × ℓd) per §25.5.2.1.
- • Class A (1.0 × ℓd) applies when ≤ 50% of bars spliced and staggered.
- • Product ψt · ψe limited to 1.7 per Table 25.4.2.4.
- • Term (cb + Ktr)/db limited to maximum of 2.5 per §25.4.2.4.
- • Hooked bar ℓdh per Eq. 25.4.3.2 with ψe, ψr, λ modifiers.
- • Headed bar ℓdh per Eq. 25.4.4.2(a), requires net bearing area ≥ 4Ab.
- • Compression splice multiplied by 2.0 when f'c < 3,000 psi.
- • Bundled bars use equivalent diameter for confinement and multiply final ℓd by 1.2 or 1.33.
- • Verify all results against the governing building code.