Use of Seismic Early Warning Information to Calibrate variable dampers for structural control of a highway bridge: evaluation of the system robustness

The seismic events occurred in recent years have highlighted the extreme vulnerability of a large part of existing constructed facilities and the need to adopt innovative solutions to improve their seismic performances. With this purpose, the possible exploitation of a seismic early warning system (SEWS) in the framework of semi-active (SA) structural control based on magnetorheological (MR) dampers is herein investigated. The main idea consists in changing the MR damper behavior according to an anticipate estimate, provided by the SEWS, of the peak ground acceleration (PGA) for an incoming earthquake. The adjustment is supposed to happen only once, just before the quake strikes. The application to a case-study problem (i.e. a highway bridge located in southern California) is shown, also allowing to assess the robustness of the proposed protection technique. Possible errors on estimation of PGA provided by SEWS and the way they affect the effectiveness of the control strategy are discussed.