Verification of damped cable system in the seismic rehabilitation of buildings

The performance capacities of the damped cable system are evaluated by the results of an experimental campaign developed on a full-scale three-story reinforced concrete structure retrofitted by this innovative protective technology. The experimental activity, carried out as part of a European Community funded Research Project, consisted in repeated series of forced vibration tests, which offered a first realistic verification of the system response capabilities. This provided essential information on the on-site behaviour of the assembled system components, among which cable connections with fluid viscous spring-dampers and story beams. The dynamic test results, elaborated in terms of equivalent transmissibility coefficients, energy dissipated by the spring-dampers and the entire structure, relevant energy ratios, and equivalent viscous damping coefficients, showed a significant improvement of structural performance in rehabilitated conditions, as well as a satisfactory correlation with design predictions. The analytical model of the structure, properly calibrated on the experimental data, was also used for a numerical seismic investigation, which confirmed the high degree of protection guaranteed by the examined technology.