Seismic response of viaducts and bridges isolated with FPS

This study deals with the evaluation of the seismic isolation of bridges equipped with single concave friction pendulum devices, by comparing the case in which the rigid abutment is present (i.e., multi-span continuous deck bridge) or not (i.e., single column bent viaduct). Two multi degree-of-freedom models are considered for the two cases, while the FPS behaviour is modelled including the velocity dependency. Furthermore, the comparison is carried out by varying the modelling parameters (i.e., pier and deck fundamental period, mass ratio and friction coefficient). The uncertainty in the seismic input is also included by subjecting the two systems to a set of different natural ground motions. The equation of motions are solved in non-dimensional form for both the models in order to obtain the maximum non-dimensional displacement of the substructure. This has led to the evaluation of the optimal sliding friction coefficient able to minimize the maximum non-dimensional pier displacement with the aim of studying the differences between the two numerical models.