ROBUST HYBRID ISOLATION SYSTEM FOR A SEISMICALLY EXCITED CABLE-STAYED BRIDGE

• Published in: Journal of earthquake engineering : JEE 2005-07, Vol.9 (4), p.497-524
• Main Authors: PARK, KYU-SIK, JUNG, HYUNG-JO, YOON, WOO-HYUN, LEE, IN-WON
• Format: Article
• Language: English
• Subjects: benchmark cable-stayed bridge; Earth sciences; Earth, ocean, space; Earthquakes, seismology; Engineering and environment geology. Geothermics; Engineering geology; Exact sciences and technology; H2 control algorithm; hybrid seismic isolation system; H∞ control algorithm; Internal geophysics; Natural hazards: prediction, damages, etc; robustness; seismic response control
• ISSN: 1363-2469; 1559-808X
• DOI: 10.1080/13632460509350553

This paper presents a robust hybrid isolation system for seismic response control of a cable-stayed bridge. Because multiple control devices are operating, a hybrid control system could alleviate some of the restrictions and limitations that exist when each control system, such as passive, active, semiactive control system, is acting alone. However, the overall system robustness may be negatively impacted by active control part of the hybrid system or active controller may cause instability due to smalt margins. Therefore, control algorithms that guarantee the controller robustness should be considered to improve the overall system robustness of the hybrid seismic isolation system and to enhance the possibility of real applications of the system consequently. In this study, a hybrid isolation system combining lead rubber bearings and hydraulic actuators is used for seismic response control of a cable-stayed bridge. Lead rubber bearings are used as passive control devices to reduce the earthquake-induced forces in the bridge and hydraulic actuators are used as active control.devices to further reduce the bridge responses, especially deck displacements. Furthermore, two kinds of robust control algorithms, i.e., the Ha and Hoo control designs with frequency weighting filters, are used to improve the controller robustness of the overall system. The numerical simulation results show that the proposed hybrid seismic isolation systems have the excellent robustnes for stiffness perturbations without loss of control performances under the considered earthquakes in this study. Therefore, the proposed robust hybrid isolation systems could effectively be used to seismically excited cabbstayed bridges.