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In this paper, a promising approach is studied that can efficiently mitigate seismic effects on a frame structure by coupling it with an protection system. Various devices are employed to achieve this objective, including tuned mass dampers, dynamic mass absorbers, elastoplastic dampers, and rocking rigid walls. This paper delves into the efficacy of a vibro-impacting nonlinear energy sink in reducing seismic effects on a frame structure. More precisely, a supplementary apparatus, consisting of an auxiliary structure equipped with a vibro-impacting nonlinear energy sink, is rigidly linked to the first story of the targeted frame structure. The seismic response of this coupled system is derived through a dynamically equivalent, low-dimensional model. As a result of the rigid connection between the frame structure and the protection system, the low-dimensional model includes only three degrees of freedom: two displacements that represent the motion of the frame structure, which is rigidly connected to the external structure, while the third characterizes the motion of the vibro-impacting mass. For the vibro-impacting nonlinear energy sink, an ideal model, which assumes instantaneous impacts, is used for the vibro-impacting mass. The proposed model is used for an in-depth parametric analysis, and the outcomes are presented in gain maps that illustrate the effectiveness of the coupling within a designated parameter plane. The findings demonstrate that the coupling with the external structure, which is equipped with a vibro-impacting mass, effectively mitigates displacements and drifts in the frame structure across a broad range of parameter values that define the protection system. [ABSTRACT FROM AUTHOR]

The flexibility of the foundation system significantly affects the seismic and operational performance of integral abutment bridges (IAB). The so-called pile isolation system can lead to higher flexibility in pile foundations. It consists in backfilling the pile hole with high-damping materials up to a certain depth from the surface level. However, the impact of this solution in increasing the lateral flexibility and reducing the seismic demand strongly depends on the scale factor and pile diameter. Most investigations on this topic are based on experimental tests on scaled pile specimens. This paper explores the pile isolation system's effectiveness by conducting a multivariate sensitivity analysis of the seismic demand of an IAB structural archetype. The IAB archetype is modelled as a Winkler beam with a piece-wise definition of the subgrade stiffness and equivalent viscous damping, simulating the responses of the soil and high-damping particles. The simulated data are then used to calibrate a probabilistic formulation of the seismic demand reduction due to the pre-hole. The formulation, calibrated following a Bayesian approach, is used to derive estimates of the q-factor associated with the damping pre-hole for possible use in engineering practice. The analyses demonstrate that pile isolation with high-damping material can be effective but possesses a limited dissipating capacity, with a seismic reduction factor of approximately 1 and 2. [ABSTRACT FROM AUTHOR]