Punching Shear Calculator

Check punching shear in slabs and footings per design codes

Input Parameters
Results
Enter your parameters and click "Calculate" to see results.
Diagram

Diagram will appear here after calculation

Notes:
  • This calculator provides preliminary results only.
  • For final design, consult a qualified structural engineer.
  • Ensure all input values are in correct units.

Formulas Used

Critical Perimeter (b0)

For internal column: b0 = 2 × (column width + column depth) + 4 × π × d

For edge column: b0 = (column width + column depth) + 2 × π × d

For corner column: b0 = (column width + column depth) + π × d

For circular column: Replace width/depth with diameter

Punching Shear Stress (τv)

τv = Vu / (b0 × d)

Where Vu is the factored shear force (axial load)

Permissible Shear Stress (τc)

IS 456:2000: τc = 0.25 × √(fck)

ACI 318-19: τc = min(0.17 × (1 + 2/β) × √(fc'), 0.083 × (αs × d/b0 + 2) × √(fc'), 0.33 × √(fc'))

Eurocode 2: τc = 0.18 × k × (100 × ρ × fck)1/3 ≥ 0.035 × k3/2 × √(fck)

Note: These are simplified formulas. Refer to the respective code for complete provisions including safety factors.

User Guide

Punching shear is a type of failure mechanism in reinforced concrete slabs and footings that occurs around concentrated loads or columns. It results from high shear stresses developing on a critical perimeter around the load.

When the shear stress exceeds the concrete's capacity, a truncated pyramid or cone of concrete "punches" through the slab, leading to sudden collapse without warning.

  1. Select the appropriate design code (IS 456, ACI 318, or Eurocode 2)
  2. Choose the column shape (square, rectangular, or circular)
  3. Enter the column dimensions (width/depth or diameter)
  4. Input the slab/footing thickness and effective depth
  5. Specify the concrete grade (fck)
  6. Enter the axial load (Pu)
  7. Check the appropriate boxes if it's an edge or corner column
  8. Click "Calculate" to see the results

The calculator compares the calculated punching shear stress (τv) with the permissible shear stress (τc) according to the selected design code.

SAFE means τv ≤ τc - the section can resist punching shear.

UNSAFE means τv > τc - the section cannot resist punching shear and requires redesign.

For unsafe sections, consider:

  • Increasing slab thickness
  • Using higher concrete grade
  • Adding shear reinforcement (shear heads, stud rails, etc.)
  • Increasing column dimensions