Design beams for combined torsion, shear, and flexure per ACI 318-19. Use for spandrel beams, edge beams, or members with significant torsional demand. Compliant with ACI 318-19 §22.7. Free to use. SI and Imperial units supported. No signup required.
Beam Torsion Design
ACI 318-19 §22.7 — Torsion design
Given ParametersInput
✓ SetThreshold TorsionACI 318-19 §22.7.4
Tth = 4.795 kN·mTorsion CapacityACI 318-19 §22.7.6
φTn = 49.32 kN·m| Step | Formula | Substitution | Result | |
|---|
| Tth | φ·0.083λ√f'c·Acp²/Pcp | 4.795 | 4.795 kN·m | |
| Step | Formula | Substitution | Result | |
|---|
| φTn | φ·2Ao·At·fy·cotθ/s | 49.32 | 49.32 kN·m | ✓ |
| Step | Formula | Substitution | Result | |
|---|
| DCR | Tu/φTn | 18/49.32 | 0.36 | ✓ |
[1]
Beam Torsion Design
ACI 318-19 §22.7
Project: N/A · Engineer: N/A · Date: 10/10/2026 · Rev: 0
[2]
Design reference: ACI 318-19 §22.7
[3]
Given:
b = 300 mm (Width)
h = 500 mm (Height)
Tu = 18 kN· m (Torsion)
Vu = 120 kN (Shear)
[4]
Material Properties:
Concrete
f'c = 30 MPa
λ = 1
Tth = 4.795 kN· m
Steel
fy = 400 MPa
s = 150 mm
Al/s = 695 mm²/m
[5]
Threshold Torsion
ACI 22.7.4
Tth = φ· 0.083λ√f'c· Acp²/Pcp
= 4.795
= 4.795 kN· m
[6]
Torsion Capacity
ACI 22.7.6
φTn = φ· 2Ao· At· fy· cotθ/s
= 49.32
= 49.32 kN· m
[7]
DCR Check
ACI 318-19 §22.7
DCR = Tu/φTn
= 18/49.32
= 0.36
[8]
Torsion DCR
PASS
DCR = (18)/(49.32) = 0.36