Punching Shear of Reinforced Concrete Slabs under Fire Conditions: Experiment vs. Design

Shear behaviour in concrete at ambient temperature is complex, and a well-researched topic. There is even less knowledge about shear in concrete subjected to the thermal gradients due to fire, with only a few experimental studies having been conducted. Fifteen model slab-column punching shear specimens were tested at both ambient and elevated temperature. These tests are some of the first to have compared the effects of different support conditions, which aimed to replicate whole structural behaviour. This paper has presented a comparison of experimental data from a punching shear test series to both Eurocode design and Muttoni’s Critical Shear Crack Theory. The analysis shows that Eurocode design is not consistently conservative, whereas a comparison to the Critical Shear Crack Theory is. The Critical Shear Crack Theory, however, capacity comparison shows large variances. The support condition is not explicitly considered in the current flat slab design for punching shear at elevated temperature, therefore an improved design approach ought to be considered.