The thesis deals with the seismic assessment of existing reinforced concrete bridges and the retrofit of piers with hollow cross-section using fibre-reinforced polymer (FRP) jackets.
An experimental campaign that comprised quasi-static cyclic tests on large-scale models of hollow piers and seismic tests on a large-scale model of a complete bridge, applying the non-linear substructuring technique in pseudodynamic testing and considering asynchronous input motion, was followed. The prototype structure was a highway bridge situated in Austria and designed in 1975. The tests demonstrated that these infrastructures represent a source of risk in seismic regions (limited deformation and energy-dissipation capacity, undesirable failure modes).
A combination of finite element method analysis and fibre modelling was used to simulate the behaviour of a specimen of a hollow pier wrapped with an FRP jacket. Good agreement was found between experimental data and numerical results. This two-level modelling approach was employed to study the effectiveness of FRP wrapping for the confinement of hollow piers with large dimensions, considering the effect of axial load, longitudinal reinforcement and dimensions of the jacket. On the basis of more than 1000 numerical analyses, an empirical design equation was elaborated.