EN 1992-1-1 punching shear at an internal circular column, slab or foundation base, with β from Expression (6.42). Open the calc and check your design.
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About this Punching Shear, Internal Circular Column Calculator
This calculator checks punching shear at an internal circular column to EN 1992-1-1 Clause 6.4, for a flat slab on the column or a foundation base under it. The control perimeters are circles around the column, and the refined eccentricity factor comes from Expression (6.42), which is written for circular columns.
- Structural engineer on a car park or podium check round columns through a flat slab, including the effect of the transferred moment on β.
- Geotechnical and footing designer check a circular pier on a pad, with the soil pressure inside each trial perimeter taken off the punching force.
- Graduate engineer follow the full Clause 6.4 sequence for a round column, from u_0 and u_1 to the reinforcement and the outer perimeter, with each step shown.
Each result traces back to an expression in the code, and changing the diameter, depth or load updates every check at once. It is an engineering-grade calculation on CalcTree that you can duplicate into your own workspace.
More info on Punching Shear at a Circular Column
Geometry and actions
The inputs are the column diameter, the effective depth and tension reinforcement in each direction, the design punching force, the moment transferred to the column, the net upward soil pressure for a base and the mean normal stresses. The column face perimeter is π times the diameter, and the basic control perimeter is the circle at 2d from the face.
Eccentricity factor options
β can be the approximate internal column value of Figure 6.21N, the refined Expression (6.42) with e = M_Ed / V_Ed, or a value you enter. On perimeters other than u_1 the diameter of that perimeter replaces D + 4d, and for a foundation base the net force at the perimeter is used.
Foundation base perimeters
For a base, Clause 6.4.4(2) calls for checks on perimeters within 2d of the column face. The page works a set of trial perimeters inside that zone, each with its own net force, β, shear stress from Expression (6.48) and enhanced resistance from Expression (6.50), and the governing one is the highest utilisation.
Reinforcement and limits
The crushing check at the column face uses Expression (6.53) with the full column force. Where the concrete alone does not suffice, Expression (6.52) gives the area per perimeter for links or a single perimeter of bent-down bars, the k_max limit is checked on u_1, and Expression (6.54) gives the outer perimeter u_out.
Common Calculation Errors to Avoid
- Applying the rectangular β formula a circular column has its own refined expression, (6.42), and the perimeter diameter changes for perimeters other than u_1.
- Forgetting the soil pressure under a base the upward pressure inside a perimeter reduces the force crossing it, which can change which perimeter governs.
- Using the wrong angle for bent-down bars α is the angle between the reinforcement and the plane of the slab: links are usually vertical and bent-down bars inclined, and the sin α term changes the area needed.
- Reading u_out as a reinforcement extent u_out is the perimeter beyond which no punching reinforcement is needed; the outermost reinforcement perimeter must sit inside it.
- Overlooking v_min the lower bound of Expression (6.3N) can govern for lightly reinforced slabs and bases.
Engineering templates
Common calculators
Design guides
FAQs
Why does a circular column need its own punching calculation?
The perimeters around a round column are circles rather than rectangles with rounded corners, and EN 1992-1-1 gives a specific refined β for circular columns in Expression (6.42). Using the rectangular expressions would give the wrong perimeter lengths and eccentricity.
Can I enter my own value of β?
Yes. Choose the entered value option and the page uses your β on every perimeter. This suits cases where β comes from a separate analysis or a national annex.
How is the governing perimeter of a foundation base found?
The page checks a set of perimeters between 0.5d and 2d from the column face, computes the utilisation on each from the net force and the enhanced resistance, and reports the perimeter with the highest utilisation.
Does the page size the punching reinforcement?
It gives the area per perimeter from Expression (6.52) for multiple perimeters of links or a single perimeter of bent-down bars, checks the k_max limit and gives the outer perimeter u_out. Detailing such as the minimum leg area is left to you.
Which parts of Clause 6.4 are outside its scope?
Openings near the column, column heads, prestressed slabs beyond the k_1 σ_cp term and the minimum area of a link leg are not covered.
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