ABSTRACT
In Chapters 2, 3, and 4, smart seismic structures using base-isolation systems, passive dampers, and active control systems have been discussed in detail. Recall that two more types of control systems were introduced earlier: semiactive and hybrid. They both combine active and passive control mechanisms and thus are both “hybrid” systems in some sense. They both gain the reliability of passive devices and adaptability of active control systems. The difference is the function of the active device of the two systems. The one in hybrid systems applies control force directly to the structure, while the one in semiactive systems adjusts the behavior of the passive device. In other words, a semiactive system has adjustable properties in real time but cannot directly apply energy to the smart structure to control its seismic response. Thus, the capacity of a semiactive system is somewhat limited by its base, a passive device. A hybrid system such as the hybrid damperactuator bracing control (HDABC) system can gain the capacity of its active control device in addition to its reliability and adaptability.
