Create punching checks in a flat slab

To create punching checks in a flat slab, do the following:

On the ribbon, go to the Design tab.
Select Punching Check.
In the Properties window, adjust the check properties according to your needs.

Note: The tension reinforcement defaults to the slab Top surface when the check is created from the Design tab. (If created from the Foundations tab the only difference is that it defaults to the Bottom surface.)
To create checks in either a 2D or 3D scene view, do one of the following:
- Hover the mouse pointer over the desired column node, wall node, or point load. When the Pick Punching Check Location tooltip appears, click to add the punching check at the selected node.
- Hold down the left mouse button and drag a box to add punching checks to all potential check locations within the box.

Create punching checks in a foundation mat

To create punching checks in a foundation mat, do the following:

On the ribbon, go to the Foundations tab.
Select Punching Check.
In the Properties window, adjust the check properties according to your needs.

Note: The tension reinforcement defaults to the mat Bottom surface when the check is created from the Foundations tab. (If created from the Design tab the only difference is that it defaults to the Top surface.)
To create checks in either a 2D or 3D scene view, do one of the following:
- Hover the mouse pointer over the desired column node, wall node, or point load. When the Pick Punching Check Location tooltip appears, click to add the punching check at the selected node.
- Hold down the left mouse button and drag a box to add punching checks to all potential check locations within the box.

Specify the axis orientation for punching checks applied to point loads

When you apply a punching check to a point load, by default the check Y and Z axes are automatically orientated to align with global X and Y.

If this is not appropriate you can manually define the punching check Z axis orientation as follows:

In the Properties window, select User loaded area.
Specify the Loaded Area Orientation angle in relation to the global Y axis.

Note:

The above doesn't apply for checks to columns because in that case the check Y and Z axes are automatically orientated to align with the column major and minor axes. The two axis systems are locked together, so if the column is rotated, the punching check axes also rotate. For more information, see: Punching shear check axis system

Override the punching check loaded area

When you apply a punching check to a point load, the default loaded area is taken as 4in x 4in (US Customary units), or 100mm x 100mm (metric units).

When you apply a punching check to a column, the loaded area is based on the column section - the default being the section boundary box.

There can be certain situations where the above defaults may not be appropriate, (for example when the check is applied to the bottom of a column attached to a base plate or pedestal).

In such situations, you can override the default and specify a User loaded area as follows:

In the Properties window, select User loaded area.
Specify the Loaded Area Breadth and Loaded Area Depth.

Confirm punching check positions

When you apply a punching check, the program automatically detects whether a slab is present in each of punching check axis directions. In the Properties window, Slab in y positive/negative and Slab in z positive/negative are set accordingly. Based on these, the punching check is assumed to be at an Internal, Edge Y, Edge Z or Corner position.

It is very easy to graphically review and modify the check position from a Review View as shown in the image below.

Alternatively, you could manually adjust the position from the Properties window as follows:

Select Slab Override
Change Slab in y positive/negative and Slab in z positive/negative as required.

Specify stud rail reinforcement

Restriction:

Stud rail reinforcement is only available for Eurocode and ACI regional codes.

To specify the reinforcement:

Create a punching check item as instructed above.
Right-click the punching check item.
In the context menu, select Edit Reinforcement.
The Punching shear reinforcement properties dialog box is displayed.
Select the Use reinforcement option.
Select whether you want to autodesign the reinforcement, and, if auto-designing, select the required reinforcement starting from parameter.
Select the reinforcement parameters according to your needs.
Adjust the stud rail parameters according to your needs.

Note: For more information about rail layout arrangements, see: Reinforcement layout.
Provided the analysis has been performed, you can run the punching shear calculations for the specified layout by selecting Check... on the right hand side of the dialog box.
When the layout is acceptable, click OK
The reinforcement data is saved to the punching check item Properties window.

Punching check properties


General
Tension Reinforcement	This setting identifies the slab reinforcement to be used in the punching check calculation. Top Bottom
Center	The check location (not editable).
Column Drop	Indicates if the check considers a Column Drop (not editable).
Beta - User limit (Head Code Eurocode)	When this checkbox is selected, a minimum value of Beta = 1.15 is applied to all internal columns.
User factor for Vt (Head Code BS)	When this checkbox is selected, the user factor for Vt is applied.
u0 - user reduction	Can be used to manually specify a reduction in the length of the u0 perimeter to account for undefined openings.
u1 - user reduction	Can be used to manually specify a reduction in the length of the u1 perimeter to account for undefined openings.
Check Status and Ratio	Indicates the status of the checks for each calculated perimeter and the overall check ratio.


Loaded Perimeter
Length	Indicates the length of the u0 Loaded Perimeter (not editable).
Reduced length	The reduced length of u0 after accounting for openings.
BEquiv, DEquiv, BBound, BBound, Bounding Perimeter	Refer to the Concrete Design Reference Guide for the current Head Code for the appropriate definition of these terms.
d Effective Depth	Indicates the average effective depth to the tension reinforcement (not editable). d = (dy + dz) / 2 where dy and dz are the effective depths in the two orthogonal directions. There is a value of d for top steel and a different value for bottom steel. Note this definition changes in the presence of a drop panel. This information is only available if the reinforcement is known in each direction.
Slab Override	When an override is applied the slabs in each direction can be de-activated in the check. In this way the Loaded Perimeter Position can be edited. Note: In the typical case of punching checks around a column, the slab ‘y’ & ‘z’, ‘positive’ & ‘negative’ are defined by the local axis system of the column. This can be displayed by displaying the Local Axes for 1D Elements in Scene Content.


Control Perimeter
Length	Indicates the length of the u1 Control Perimeter (not editable).
Reduced length	The reduced length of u1 after accounting for openings.
[-] Design Input (Head Code Eurocode and ACI)
Use Reinforcement	Select this checkbox in order to apply a default punching reinforcement arrangement that can then either be checked, or used as the starting reinforcement for an auto-design. You would only choose to clear the checkbox when specifying a new check if you want to perform an auto-design but starting from Minima.
Reinforcement type	In the current release only Stud reinforcement is considered.
Arrangement type	The options are: • Orthogonal (default) • Circular
Auto-design	When run in Auto-design mode, the reinforcement is increased until either a pass is achieved or the limiting reinforcement parameter limits have been exceeded.
Select reinforcement starting from	This option controls the starting point for auto-design procedures and is therefore only displayed if Auto-design is ‘on’. • Minima - removes the current arrangement and begins with the minimum allowed bar size. • Current - auto-design commences from the current bar arrangement.
Rib type	Specifies the reinforcement rib type.
Grade	The reinforcement grades that are available here are set from the Materials button on the Home ribbon.
Bar size	The reinforcement bar sizes that are available here are set from the Materials button on the Home ribbon.
Spacing	Defines the spacing between bars along each rail.
Spacing from column face	Defines the spacing of the first bar in each rail from the column face.
Stud rails spacing in Y direction	Spacing between rails in the local Y direction.
Stud rails spacing in Z direction	Spacing between rails in the local Z direction.
Number of diagonal stud rails on one corner	The number of stud rails adjacent to each corner of the column. (This property is only displayed when the ‘Arrangement Type’ is Circular)
Number of studs per column face - Y direction	The number of stud rails adjacent to the column face in the local Y direction.
Number of studs per column face - Z direction	The number of stud rails adjacent to the column face in the local Z direction.
Number of studs per rail	Number of studs on each rail.


Utilization ratio
Apply (to autodesign)	On When an Autodesign is performed, the design will be incremented to achieve a utilization ratio less than the ratio limit. Off When an Autodesign is performed, the design will be incremented to achieve a utilization ratio less than 1.0. See: Apply user defined utilization ratios
Apply (to check)	On When a Check is performed, the check will pass provided the utilization ratio is less than the ratio limit. Off When a Check is performed, the check will pass provided the utilization ratio is less than 1.0.
Ratio limit	The utilization ratio against which the autodesign or check is performed (when applied above).


Design Input (Eurocode and ACI only)
Use Reinforcement	Select this checkbox in order to apply a default punching reinforcement arrangement that can then either be checked, or used as the starting reinforcement for an auto-design. You would only choose to clear the checkbox when specifying a new check if you want to perform an auto-design but starting from Minima.
Reinforcement type	In the current release only Stud reinforcement is considered.
Arrangement type	The options are: • Orthogonal (default) • Circular
Auto-design	When run in Auto-design mode, the reinforcement is increased until either a pass is achieved or the limiting reinforcement parameter limits have been exceeded.
Select reinforcement starting from	This option controls the starting point for auto-design procedures and is therefore only displayed if Auto-design is ‘on’. • Minima - removes the current arrangement and begins with the minimum allowed bar size. • Current - auto-design commences from the current bar arrangement.
Rib type	Specifies the reinforcement rib type.
Grade	The reinforcement grades that are available here are set from the Materials button on the Home ribbon.
Bar size	The reinforcement bar sizes that are available here are set from the Materials button on the Home ribbon.
Spacing	Defines the spacing between bars along each rail.
Spacing from column face	Defines the spacing of the first bar in each rail from the column face.
Stud rails spacing in Y direction	Spacing between rails in the local Y direction.
Stud rails spacing in Z direction	Spacing between rails in the local Z direction.
Number of diagonal stud rails on one corner	The number of stud rails adjacent to each corner of the column. (This property is only displayed when the ‘Arrangement Type’ is Circular)
Number of studs per column face - Y direction	The number of stud rails adjacent to the column face in the local Y direction.
Number of studs per column face - Z direction	The number of stud rails adjacent to the column face in the local Z direction.
Number of studs per rail	Number of studs on each rail.