Experimental study on the cyclic response of an existing R.C. bridge pier

This paper deals with experimental activity on piers belonging to an old viaduct of the Italian highway network. The tests consist of cyclically imposed displacement to a 1:4 scale of one of the piers, performed in the laboratory of the department of structures of the University of Roma Tre. The objectives of the experimental campaign is twofold: 1) evaluation of the failure mechanisms and collapse strength of the pier, 2) calibration of a numerical non-linear model using Opensees code, in order to simulate the seismic behaviour of the analyzed bridge. The experimental test performed on the first mock-up has shown that the shear behaviour is extremely relevant. In particular, the shear failure of the transverse beam highly influences the global cyclic behaviour of the specimen, with a pronounced pinching effect that reduces the dissipation capability of the pier. Moreover, other less relevant phenomena are observed: bond-slip of the reinforcing bars and buckling of the longitudinal steel bars of the column. A numerical model built in Opensees has been calibrated in order to reproduce the experimental results and provide a reliable model for further seismic analyses. Using literature models to reproduce the experimentally observed phenomena, the model has been able to simulate the real behaviour of the specimen in a satisfactory way.