Seismic response of steel frames with hysteretic dampers designed according to second generation of Eurocode 8 and comparison with conventional frames

This paper investigates the seismic response of a steel moment-resisting frame with hysteretic energy dissipation devices, designed with the energy-balance-based method implemented in the forthcoming second generation of Eurocode 8. Its response is compared with that of a counterpart conventional frame without energy dissipation devices designed under the force-based approach, also following the second generation of Eurocode 8. The response of both systems is obtained through nonlinear time history analyses with a suite of scaled accelerograms. The results of these analyses serve as well to judge the goodness of the prediction -in terms of maximum interstory drifts and energy dissipation demands- of the energy-balance-based method. Both structures are assumed to be in a region of high seismicity. A quantitative comparison is also made in terms of residual displacements and amount of steel required, and cost. The results demonstrate that the energy-based formulation of the second generation of Eurocode 8 provides for structures with much better performance and lower cost than conventional steel frames designed according to the force-based approach. It is furthermore shown that the energy-balance-based method affords a safe-side estimation of the maximum interstory drifts and of the expected damage on the main structure of the system with energy dissipation devices. The latter consumes about one half of the steel required by the conventional structure, while reducing the maximum interstory drifts to nearly one half and the residual drifts to nearly one third.