PhD exam

Danilo Tarquini defended successfully his PhD thesis "Out-of-plane stability of thin reinforced concrete walls under seismic loading". The members of his committee were Prof. Laura Lowes (University of Genova, Italy), Prof. Bozidar Stojadinovic (ETH Zurich), Prof. Aurelio Muttoni (EPFL), Dr. Anastasios Vassilopoulos (EPFL, chair), Prof. João Almeida (UC Louvain, co-advisor) and Prof. Katrin Beyer (EPFL, advisor).

With his thesis, Danilo Tarquini provides new experimental evidence and models of the deformation capacity of lap splices subjected to monotonic and cyclic loading. Danilo Tarquini tested 24 axially loaded members with and without lap splices of various lengths and with different confinements, subjected to a range of loading histories. The test units were heavily instrumented, using optical measurements to determine the deformations along the element but also the slip between bars and concrete. From this data, Danilo Tarquini derived new deformation limits of lap splices. He extended the existing tension-chord model to axial members with lap splices, reproducing very well the experimentally observed force-displacement response as well as the crack width distribution along the member. To valorize fully the improved deformation capacity limits for lap splices when analyzing reinforced concrete elements, finite element models are required that estimate reliably the deformation demand in the lap splice region. For this purpose, Danilo Tarquini developed a displacement-based beam element but enforces axial equilibrium at the integration points. This results in a more realistic curvature profile and therefore in better estimates of strain demands.

With his experimental, numerical and analytical work, Danilo Tarquini advanced our understanding of the deformation capacity of lap splices under cyclic loading. By making all his research results including the experimental data and numerical models openly available, he facilitates and encourages future research on this challenging topic.

The research project was financed by the Federal Road Authority of Switzerland.