A METHODOLOGY FOR THE DESIGN OF ENERGY DISSIPATION DEVICE FOR THE SEISMIC PROTECTION OF BRIDGES

The present work aims at establishing design criteria for a rational use of the elastic-plastic devices employed for the seismic protection of bridge structures. The proposed target is attained via an energy based approach which is formulated as an optimum problem. An appropriate non dimensional index, related to both dissipated and input energy, is assumed as a measure of the optimum performance of the device, which is constrained to comply with service and ultimate conditions of the structure. Preliminary numerical results, concerning single degree of freedom systems, show that it is possible to construct optimal design graphs that depend on only two constitutive parameters of the device: yield force and elastic stiffness. Further curves are also given which allow to perform on a "a posteriori" check of both the relevant structural response quantities and the damage level suffered by the device.