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Proceedings of the International Conference on 503
Advances and New Challenges in Earthquake
Engineering Research, Hong Kong Volume
SEISMIC RESPONSE CONTROL OF A BENCHMARK
CABLE-STAYED BRIDGE
J. N. Yang 1 , S. Lin 1 and F. Jabbari 2
Department of Civil and Environmental Engineering
Department of Mechanical and Aerospace Engineering
University of California, Irvine, CA 92697, USA
ABSTRACT
Control systems have been shown to be quite effective in reducing the seismic response of buildings and
bridges. In this paper, two HZ based control strategies with energy-bounded or peak-bounded excitations
are proposed and their applications to the seismic response control of a benchmark cable-stayed bridge
are presented. For design loads specified by a class of "energy-bounded" or peak-bounded excitations,
both controllers are derived by minimizing the upper bound of the HI performance. The design syntheses
of these control strategies are developed and formulated within the framework of linear matrix
inequalities (LMIs), so that the LMI toolbox in MALAB can be used effectively and conveniently. The
performance of these two control strategies is demonstrated using a seismically excited benchmark
cable-stayed bridge. Simulation results indicate that: (i) the performance of the proposed control
strategies is excellent in comparison with that of the LQG sample controller, and (ii) the seismic
response of the cable-stayed bridge can be reduced significantly through the application of the control
technology.
INTRODUCTION
It has been shown that various control systems can be used effectively to reduce the response of civil
engineering structures subject to strong winds, earthquakes and other service loads [e.g., Housner et al
(1997), Spencer and Sain (1997), Yang et ai (2QOOb,c; 2002a,b)]. Benchmark problems for control of
buildings and bridges have been established recently [ e.g., Spencer et al (1998), Ohtori et al (2000),
Yang et al (2000a), Dyke et al (2000) ]. The response control of long-span cable-stayed bridges has
attracted considerable attention [e.g., Yang et al (1979a,b), Warnitchai et at (1993), Achkire & Preumont
(1996), Johnson et al (2002) ]. In particular, the connection between the bridge deck and towers affects
the seismic response of cable-stayed bridges. Under seismic excitations, a strong connection will reduce
the displacement response of the deck and increase the shear force and bending moment at the base of
the towers. A weaker connection can be used as a compromise between the deck displacement and forces
at the base of the tower to restrict the deck motion during small earthquakes. During strong earthquakes,
the weaker connection will be damaged to allow a large deck motion thus preventing damages to the
tower. Another approach is to dissipate the vibration energy of the bridge using active, passive,