Fire performance of headed shear studs in profiled steel sheeting

The fire performance of shear connections is essential to maintain a composite action in composite beams, for which studies have previously focused on solid slab structures. Despite the popularity of profiled steel sheeting in modern construction, the behaviour of shear studs embedded in transverse deck slabs still needs to be confirmed under elevated temperatures. High-temperature push-out tests were conducted according to the ISO 834 standard fire condition with customised electric furnaces, which showed a failure mode transition with rising temperature. A three-dimensional thermomechanical numerical model was developed and compared with the experimental results for verification. A parametric study revealed that the shear connections were primarily influenced not by the deck thickness or stud welding method but by the temperature distribution, especially around the stud root area. Eurocode 4 utilises a thermal degradation factor as well as shear resistance at ambient condition to calculate the load-bearing capacity at fire condition, resulting in a highly conservative estimation. A better prediction was achieved by omitting the deck reduction factor for stud shearing failure. A new design formula that considers the failure mode transition is thus proposed for a concrete-dominated failure.