Feedforward Control Algorithms For Seismic Early Warning Systems

Recent impulses on the development of seismic early warning systems (SEWS) is opening the way toward innovative applications of structural control. Generally speaking, a seismic SEWS is a set of actions that can be taken from the moment when a seismic event is triggered with a significant reliability to the moment the quake strikes in a given location. This information can be very conveniently used to prevent devastating damages, by the knowledge, ahead of time, of the event that isoccurring in order to decide what has to be done to the built environment to reduce the overall risk. The leading (pre-information) time can be currently estimated in the range of few seconds to dozens of seconds. Current research activities on SEWS include the anticipate estimate of peak ground acceleration and/or response spectrum. Quality and reliability of the anticipate information vary in time, being more and more accurate from the time a quake strike at the epicenter to the moment the ground motion arrives at a selected location. Possible interaction between SEWS and Structural Control is a quite recent subject still to be fully investigated. However, the possibility of knowing the incoming ground motion ahead of time opens new scenarios about the adoption of feed-forward control algorithms, so far almost neglected in the context of structural control.