Punching shear is a type of failure of reinforced concrete slabs subjected to high local forces. In flat slab structures, this occurs at column support points. The failure is due to shear. This type of failure is critical because no visible signs are shown prior to failure.
You can check if the required longitudinal slab or foundation reinforcement is adequate to resist the local shear force at the support. Moreover, you can proceed with the calculation and design of the required shear reinforcement around the support, if necessary.
Punching shear design / check (Steps of calculation)
The 'Punching design' command enables you to calculate and the design the punching reinforcement for selected nodes using EN 1992-1-1:2004/A1:2014.
All necessary input data for calculation are automatically prepared from the model, followed by a procedure to construct the basic critical control perimeter as a base to verify the concrete capacity of a member without punching reinforcement.
If the concrete capacity without shear reinforcement is insufficient, punching reinforcement is designed.
The whole calculation is described in a brief output together with the presentation of results in a graphical window.
Internal, edge, and corner nodal or column supports with rectangular or circular shape of the loaded area are supported.
User workflow and supported features
Both design and checks of punching reinforcement are supported. The workflow is quite simple. You just model 2D members and under the concrete service you run the punching shear design. There is no need to assign special data to the slab-column connection. All the concrete parameters are automatically taken from the concrete settings.
The following features are supported in term of punching shear checks and design.
1. Calculation of a flat slab or foundation resistance for shear according to Eurocode EN 1992-1-1 and NA.
2. Circular and rectangular columns are supported only. You can also use a standard support to simulate a column support.
3. Calculation of the critical control perimeters using a set of trails to find the more critical one.
4. Different possibilities for selection of nodes.
5. Both required and user provided reinforcement are supported for the calculation of a slab / foundation resistance.
6. Different possibilities to calculate β-factor:
Approximate method according to EC2/ 6.3.4(6)
With the requirement of NA depending on support position taken into account
Formulas from EC2/ 6.4.3(3-5)
7. Easy to understand whether the 2D members need punching shear reinforcement or not.