Concrete Column Capacity Calculator (ACI 318-19)

How It Works

1. Define Column Geometry

   Choose square, rectangular, or circular cross-section. Enter the dimensions. Select tied or spiral confinement.

2. Set Material Properties

   Choose concrete strength f'c (3,000-10,000 psi) and steel grade fy (typically 60,000 psi). Enter reinforcement by bars (size and count) or by target reinforcement ratio.

3. Enter Length and End Conditions

   Enter the unsupported length and effective length factor K (1.0 for pinned-pinned, 0.65 for fixed-fixed, etc.) for the slenderness check.

4. Review Capacity

   The calculator shows φPn (max axial capacity), reinforcement ratio, slenderness classification, and minimum tie/spiral requirements. Enter an applied factored load for utilization check.

Built For

• Structural engineers performing preliminary column sizing for concrete frame buildings
• Concrete contractors verifying column reinforcement against design loads
• Engineering students studying ACI 318 column design provisions
• Building officials reviewing submitted column calculations for code compliance
• Architects evaluating column sizes during schematic design for space planning

References

1. ACI 318-19 , Building Code Requirements for Structural Concrete, Chapters 10 and 22
2. ACI SP-17 , The Reinforced Concrete Design Handbook (Column Interaction Diagrams)
3. ACI Detailing Manual , SP-66 (Reinforcement Detailing)
4. CRSI Design Handbook , Concrete Reinforcing Steel Institute

Frequently Asked Questions