Eurocode 2 Punching Shear Calculator (EN 1992-1-1)

Check punching shear for flat slabs and pad foundations around internal columns according to Eurocode 2. Calculates control perimeter, design shear stress, concrete resistance, and required shear reinforcement.

Punching Shear Design – Internal Column

Geometry & Materials

Distance from compression face to centroid of tension reinforcement.

Average of top & bottom reinforcement in orthogonal directions within 3d of column.

Design Shear & NA Parameters

Net design shear at column face after subtracting self-weight inside column perimeter if applicable.

β = 1.0 for concentric loading; increase for unbalanced moments (see EC2 6.4.3(3)).

Used in vRd,c = max{ [CRd,c k (100ρl fck)1/3], [vmin + k1 σcp] }.

Optional beneficial compressive stress (e.g. prestress). Often 0 for ordinary slabs.

Design yield strength of punching shear studs or stirrups.

Results

Overall punching shear check

Awaiting input

Enter geometry and loads, then click “Calculate punching shear” to see utilisation and required shear reinforcement.

Control perimeter u1 at 2d

  • Perimeter distance from column face: – mm
  • Control perimeter u1: – mm
  • Effective depth factor k: –

Design shear stresses

  • Design shear stress vEd: – MPa
  • Concrete resistance vRd,c: – MPa
  • Max resistance vRd,max: – MPa
  • Utilisation vEd/vRd,c: –
  • Utilisation vEd/vRd,max: –

Assumptions & limitations

  • Internal column in a flat slab or pad foundation.
  • No openings or significant stiffness changes within 3d of the column.
  • Shear force VEd already includes effects of unbalanced moments via β.
  • National Annex parameters (CRd,c, k1, vmin) are taken as common defaults – adjust as required.

How the Eurocode 2 punching shear check works

Punching shear is a local failure mode of flat slabs and pad foundations around concentrated loads or columns. Eurocode 2 (EN 1992-1-1, clause 6.4) checks the design shear stress at a control perimeter around the column against the concrete resistance and, if necessary, designs shear reinforcement.

1. Control perimeter u1 at 2d

For an internal column, the basic control perimeter u1 is taken at a distance 2d from the column face (EN 1992-1-1, 6.4.2). For a rectangular column with side lengths cx and cy:

u1 = 2 (cx + cy + 4d)

The calculator assumes an internal column and uses this expression. For edge or corner columns, or for columns near openings, the control perimeter must be reduced and the shear distribution modified according to the code.

2. Design shear stress vEd

The design shear stress at the control perimeter is:

vEd = β · VEd / (u1 · d)

  • VEd – design shear force at the column (kN).
  • β – factor accounting for non-uniform shear due to unbalanced moments (β = 1.0 for concentric loading).
  • u1 – control perimeter at 2d (mm).
  • d – effective depth (mm).

3. Concrete punching shear resistance vRd,c

For slabs without shear reinforcement, Eurocode 2 gives the design punching shear resistance:

vRd,c = max { CRd,c · k · (100 ρl fck)1/3 ; vmin + k1 σcp }

k = 1 + √(200 / d) ≤ 2.0

vmin = vmin,factor · k3/2 · fck1/2

  • ρl – average flexural reinforcement ratio in both directions within 3d of the column.
  • fck – characteristic cylinder strength of concrete (MPa).
  • σcp – average compressive stress (e.g. from prestress), often 0.
  • CRd,c, k1, vmin,factor – National Annex parameters (defaults: 0.18/γc, 0.15, 0.035).

4. Maximum punching shear resistance vRd,max

Even with shear reinforcement, the design shear stress must not exceed the maximum resistance of the concrete compression struts:

vRd,max = 0.5 · ν · fcd

ν = 0.6 · (1 − fck / 250)

fcd = αcc fck / γc    (αcc ≈ 1.0)

If vEd > vRd,max, increasing shear reinforcement alone is not sufficient – you must increase the slab thickness, column size, or provide a drop panel / column capital.

5. When is punching shear reinforcement required?

  • No reinforcement required if vEd ≤ vRd,c.
  • Shear reinforcement required if vRd,c < vEd ≤ vRd,max.
  • Design not adequate if vEd > vRd,max.

This calculator reports the utilisation ratios vEd/vRd,c and vEd/vRd,max, and, where applicable, an indicative shear reinforcement demand.

6. Indicative punching shear reinforcement demand

When vEd exceeds vRd,c, the excess shear must be carried by shear reinforcement. The calculator estimates:

VEd,red = (vEd − vRd,c) · u1 · d

and an indicative reinforcement ratio ρw based on the design yield strength fywd. In practice, you will select a stud rail or stirrup layout (bar diameter, spacing, number of perimeters) and verify all detailing rules in EN 1992-1-1, 6.4.5.

Typical design workflow

  1. Define slab thickness, effective depth, and column dimensions.
  2. Estimate the average flexural reinforcement ratio ρl near the column.
  3. Calculate the design shear VEd at the column from your load analysis.
  4. Choose β based on the amount of unbalanced moment transferred.
  5. Run this calculator to obtain vEd, vRd,c, vRd,max, and utilisation.
  6. If required, design punching shear reinforcement and check detailing.

Frequently asked questions

Can I use this for edge or corner columns?

No. This version is limited to internal columns. For edge and corner columns, the control perimeter is reduced and the shear distribution is more complex. You should follow EN 1992-1-1, 6.4.3 and your National Annex, or use specialised software.

How should I choose β?

For concentric loading, β = 1.0. For significant unbalanced moments, β is typically between 1.1 and 1.5 depending on the eccentricity and reinforcement layout. Many National Annexes provide guidance or recommended values.

Does the tool account for openings near the column?

No. Openings within 3d of the column can significantly reduce the effective control perimeter. If you have such openings, you should either reduce u1 manually according to the code and input an equivalent VEd, or use a more advanced punching shear design tool.

Is this calculator a substitute for a full code check?

It is intended as a fast, transparent aid for preliminary and routine design checks. Final designs should always be reviewed by a qualified structural engineer and checked against the full text of EN 1992-1-1 and the relevant National Annex.