Effectiveness and robustness of a semi-active control strategy based on seismic early warning information

Abstract

A smart passive control strategy is herein investigated to protect seismically excited structures. It is based on the use of seismic early warning information to optimally calibrate variable dampers for an higher reduction of the structural response. In particular, the adoption of magnetorheological dampers calibrated according to the forecasted value of the seismic peak ground acceleration is proposed. Such variation of the devices' behavior is supposed to be commanded once few seconds before the earthquake actually arrives to strike the site and to be kept constant for the whole duration of the excitation. The effectiveness of such control technique is demonstrated with reference to a case-study structure consisting in a highway bridge located in Southern California. Several nonlinear time-history analyses using seismic registrations of natural events very different each other for magnitude, peak ground acceleration, and soil types have been performed. The results in terms of reduction in seismic demand are further compared with those other control techniques from literature, applied to the same structure, lead to. The final part of the paper is dedicated to evaluate if and how possible errors related to the peak ground acceleration estimate may affect the efficacy of the proposed strategy in reducing structural response. The control technique resulted to be promising for the ease of implementation for structures already served by a seismic early warning network, effectiveness, even compared with active control systems, and robustness.