Performance-based retrofit of a prestressed concrete road bridge in seismic area

"The paper deals with the proposal of a procedure for the seismic retrofit of an existing prestressed concrete bridge. First, the seismic vulnerability assessment of the bridge was carried out. With this aim, a Nonlinear Static Procedure based on the Capacity Spectrum Method as well as the Inelastic Demand Response Spectra was applied. According to the Performance-Based Earthquake Engineering principles, these procedures make it possible to explicitly correlate the different performance levels to the varying intensities of seismic action. A seismic protection strategy based on the use of FPS isolating system located between pier top and deck was subsequently applied. A design process consisting of an appropriate application of capacity-design principles and the Direct Displacement-Based Design approach was implemented. Finally, the seismic response of the bridge was evaluated through a nonlinear time-history analysis with the direct integration of the motion equations, with the results highlighting the effectiveness of the seismic retrofit strategy.