Flat plate concrete structures are easy to construct and cheap to build. However, they are susceptible to a type of brittle failure known as “punching shear”, where columns punch through the floor leading to progressive collapse. This is a particularly…
Flat plate concrete structures are easy to construct and cheap to build. However, they are susceptible to a type of brittle failure known as “punching shear”, where columns punch through the floor leading to progressive collapse. This is a particularly dangerous type of failure as it occurs suddenly and without warning. A finite element model was developed and validated based on the author’s previous tests for a square slab with a single column stub. This arrangement simulates the type of column to slab arrangement found in many office buildings. The failure mechanics were examined and the model gave a good agreement with the experimental results identifying the correct crack pattern and the failure loads. A 2-d axisymmetric model was then developed representing a circular column to model the punching crack propagation in detail. This was done using the extended finite element method (XFEM). The XFEM results showed the good agreement between crack location and areas of highest principal strain and were able to capture crack propagation and the effect this has on the stress state under punching failure. It is concluded that explicit modelling of fracture is beneficial in order to capture the full response of the slab and that continuum models are insufficient to do this.