Column Punching Check
|
You can perform punching checks according to the selected concrete code using the “Column Punching Check” option located in the “Design” tab.
|
The punching check calculations have been designed for flat slab structures and raft foundations. Therefore, the stiffness of any connecting beams (if they exist) are not considered in the calculations.
The punching check is applied only to the selected members, or if no selection exists, then all columns and walls in the storey will be checked.
Alternatively, you can make a single column or wall selection and use the right-click shortcut menu to check the selected member.
Punching Shear Check Dialog:
- Floor Slab Merging Options - These options would be used in cases where the punching perimeters are not found. (generally in complex slab geometry) Refer to the slab merging part in Column Punching Shear Check Design Guide for more details.
- Check Column Perimeter and Check Column Drop Panel Perimeter (only active if a drop has been defined) – These options allow the check on maximum shear capacity at the face of the loaded area to be toggled on and off.
- Periphery Reduction Amount – An allowance for holes that have not been modelled or may be cut in the future.
- Include Load Within Punching Perimeter – When this option is checked, the shear load considered on each successive punching perimeters will reduce (due to the increasing area of loading that falls within the punching perimeter). When un‐checked the shear load will be the same on all perimeters – i.e. the check becomes more conservative.
- Column Location - In this field, users have to pick the location of the column in flat slabs (internal/ edge/corner) to determine the equation for shear checks.
-
Slab Reinforcement X and Y - Diameter of slab reinforcement and spacing must be input in this field to obtain the provided reinforcement, Ast.
-
Calculate - This
button performs the punching check and results are displayed in the report preview window.
Punching perimeters of the selected columns are automatically determined and shown in the plan view for visual confirmation.
Punching perimeters are color coded:
-
A Green perimeter indicates that the column satisfies the punching check.
-
A Red perimeter indicates that the column fails the punching check.
-
Excluded regions of the punching perimeters (due to the existence of holes, along the edges of the slabs etc.) are drawn using a block color.
For circular columns, the same principle applies ‐ BS8110 only considers idealised rectangular perimeters so checks should be made using the rectangular as opposed to the circular setting.
Users are advised to read through Punching Shear Check Design Guide, the example given in the design guide would be helpful for explaining to users the punching shear check concept.