PhD exam

Ioannis defended successfully his PhD thesis "Seismic behaviour of slab-column connections without transverse reinforcement". The members of his committee were Prof. M. B. Hueste (Texas A&M, US), Prof. W. Kaufmann (ETHZ), Dr. P. Lestuzzi (EPFL), Prof. A. Martinoli (EPFL, exam president) and Prof. Aurelio Muttoni and Katrin Beyer (PhD advisors). Ioannis Drakatos developed models for predicting the strength and the deformation capacity of slab-column connections under seismic loading. The focus of his work was on the effect of cyclic loading on the deformation capacity. To investigate this effect experimentally, he tested 13 full-scale isolated slab-column connections without shear reinforcement. The test series allowed to compare the response of monotonically and cyclically loaded slabs for different gravity shear ratios and reinforcement ratios. Ioannis Drakatos then extends the model of the Critical Shear Crack Theory for slab-column connections to seismic loading, considering the monotonic load case and the cyclic load case. The model was validated against the own tests as well as tests published in the literature. The comparison shows a very good performance. The thesis concludes with the proposal of an effective beam width model that allows estimating the deformation demand on slab-column connections from elastic finite element analysis. His PhD work was financially supported through a grant of the Swiss National Science Foundation and a grant of the cemsuisse foundation (association of the Swiss cement producers).