Semi-active control of the benchmark highway bridge based on seismic early warning systems

Possible interactions between seismic early warning systems and structural control are herein investigated. A SEWS can provide the knowledge of some parameters, ahead of time, of the seismic event that is going to occur in a certain site. Current research activities on SEWS include the estimate of the anticipated peak ground acceleration (PGA) and the acceleration response spectrum (Sa) of an incoming earthquake. This paper proposes the exploitation of this information in the framework of semi-active (SA) control strategies, by using magnetorheological dampers. The latter are time-varying properties devices able to achieve a wide range of physical behaviours using low-power electrical currents. The main idea of this work consists in changing the MR damper behaviour according to the forecasted intensity of an incoming earthquake provided by the SEWS, in order to obtain the optimal seismic response of the hosting structure. This is investigated assuming a case-study problem. It consists in the 91/5 highway bridge located in Orange County of southern California and proposed in literature as a benchmark structure for applications in the field of structural control. The effectiveness of the proposed control strategy is assessed and compared to more consolidated control techniques.