Diamonds

⌘K
  2. Home
  3. /
  4. Docs
  5. /
  6. Diamonds
  7. /
  8. Concrete design
  9. /
  10. Reinforcement calculation
  11. /
  12. Punching shear calculatio...

Punching shear calculation in footings

Diamonds automatically verifies the punching shear for footings defined using the button .
You can edit the parameters used during the punching shear check this way:

  • Go to the reinforcements results .
  • Choose the punching shear reinforcement . 
  • Select the footing(s) and click with the right mouse button in the drawing area of Diamonds. The following dialogue appears:
  • Diamonds uses default values for the parameters below, but you can easily adjust their values. This allows you to optimise your design without having to repeat the elastic analysis and reinforcement calcualtions over and over again. You just play with the parameters below until you have the desired design. Then you go to the geometry configuration and make the relevant changes (if there are any).
    • The contact surface corresponds to the area subject to the concentrated load.
      When a column was modelled and drawn, the shape and dimensions of the zone subject to the concentrated load are known.
      When a load was modelled at the location of the column or the point load is caused by a support, Diamonds uses a circle with a diameter of 20 cm.
    • Thickness and concrete cover of the slab.
      When several slabs of different thickness are considered, Diamonds takes only the lowest thickness into consideration.
    • Main reinforcement
      The punching shear resistance is calculated using the maximum value of the theoretical tensile reinforcement calculated by Diamonds and the practical reinforcement defined by you in the point where the verification is carried out. When reinforcement is present in the two orthogonal directions (A_x and A_z), Diamonds will use \sqrt{A_x \cdot A_z}.
      When Diamonds was unable to calculate the longitudonal reinforcement, it will use the minimum reinforcement.

      However, the default main reinforcement used by Diamonds is often a peak value! Because points are sensitive to peaks. It is advised to define the practical reinforcement or enter the practical reinforcement amount after “Main reinforcement”.

Notes:

  • For a footing, the contours to be verified must lay within a distance between d and 2d from the edge of the column (EN 1992-1-1 §6.4.2 (2)).
  • If punching shear reinforcement is required, Diamonds will increase the contour with a distance +0.5d until there is no longer need for punching shear reinforcement.
    The reinforcement calculated this way for a reference contour should, theoretically, be applied between the edge of the column and the contour itself. This is why the quantities of punching shear reinforcements are always expressed in mm²/m².
  • Diamonds uses the default values for β given in EN 1992-1-2 Figure 6.21N. It is not possible to make Diamonds take a different β coefficient into account.
    • β = 1,15 for a center column
    • β = 1,5 for a corner column
    • β = 1,4 for an edge column
  • In the case of a honeycomb slab, Diamonds takes the minimum thickness for the entire surface into account.

On this page