# 사장교를 위한 LRB-기반 복합 기초격리 시스템

• 정형조 (세종대학교 토목환경공학과) ;
• 박규식 (한국과학기술원 건설 및 환경공학과) ;
• ;
• 이인원 (한국과학기술원 건설 및 환경공학과)
• Published : 2004.06.01

#### Abstract

This paper presents LRB-based hybrid base isolation systems employing additional active/semiactive control devices for mitigating earthquake-induced vibration of a cable-stayed 29 bridge. Hybrid base isolation systems could improve the control performance compared with the passive type-base isolation system such as LRB-installed bridge system due to multiple control devices are operating. In this paper, the additional response reduction by the two typical additional control devices, such as active type hydraulic actuators controlled by LQG algorithm and semiactive-type magnetorheological dampers controlled by clipped-optimal algorithm, have been evaluated bypreliminarily investigating the slightly modified version of the ASCE phase I benchmark cable-stayed bridge problem (i.e., the installation of LRBs to the nominal cable-stayed bridge model of the problem). It shows from the numerical simulation results that all the LRB based hybrid seismic isolation systems considered are quite effective to mitigate the structural responses. In addition, the numerical results demonstrate that the LRB based hybrid seismic isolation systems employing MR dampers have the robustness to some degree of the stiffness uncertainty of in the structure, whereas the hybrid system employing hydraulic actuators does not. Therefore, the feasibility of the hybrid base isolation systems employing semiactive additional control devices could be more appropriate in realfor full-scale civil infrastructure applications is clearly verified due to their efficacy and robustness.

#### References

1. Skinner, R. I., Robinson, W. H., and Mcverry, G. H., An introduction to seismic isolation. John Wiley and Sons, Inc., New York, 1993
2. Naeim, F., and Kelly, J. M., Design of Seismic Isolated Structures, John Wiley and Sons, Inc., New York, 1999
3. Ali, H. M., and Abdel-Ghaffar, A. M., 'Seismic Passive Control of Cable-Stayed Bridges,' Shock and Vibration, Vol. 2, No. 4, 1995, pp. 259-272 https://doi.org/10.1155/1995/918721
4. Ali, H. M., and Abdel-Ghaffar, A. M., 'Modeling the Nonlinear Seismic Behavior of Cable-Stayed Bridges with Passive Control Bearings,' Computers and Structures, Vol. 54, No. 3, 1995, pp. 461-492 https://doi.org/10.1016/0045-7949(94)00353-5
5. Housner, G. W., Bergman, L. A., Caughey, T. K, Chassiakos, A. G., Claus, R. O., Masri, S. F., Skelton, R. E., Soong, T. T., Spencer, B. F., and Yao, J. T. P.,'Structural Control: Past, Present, and Future,' Journal of Engineering Mechanics, ASCE, Vol. 123, No. 9, 1997, pp. 897-971 https://doi.org/10.1061/(ASCE)0733-9399(1997)123:9(897)
6. Reinhorn, A. M., Soong, T. T., and Wen, C. Y., 'Base-Isolated Structures with Active Control,' Proc., ASME PVP Conf, PVP-127, 1987, pp. 413-420
7. Soong, T. T. and Spencer, Jr. B. F., 'Supplemental Energy Dissipation: State-of-the-Art and State-of-the-Practice,' Engineering Structures, Vol. 24, No. 3, 2002, pp. 243-259 https://doi.org/10.1016/S0141-0296(01)00092-X
8. Iemura, H., Adachi, Y., and Pradono, M. H., 'Seismic Retrofit of a Cable-Stayed Bridge with Dynamic Response Control Devices,' The $14^{th}$ KKNN Symposium on Civil Engineering, 2001, pp. 95-100
9. Iemura, H., and Pradono, M. H, 'Passive and Semi-Active Seismic Response Control of a Cable-Stayed Bridge,' Journal of Structural Control, Vol. 9, 2002, pp. 189-204 https://doi.org/10.1002/stc.12
10. Park, K. S., Jung, H J., and Lee, I. W., 'Hybrid Control Strategies for Seismic Protection of Benchmark Cable-Stayed Bridges,' Proceedings of the 7th U.S. National Conference on Earthquake Engineering (CD-Rom), Boston, USA, 2002
11. Park, K. S., Jung, H. J., and Lee, I. W., 'Hybrid Control Strategy for Seismic Protection of a Benchmark Cable-Stayed Bridge,' Engineering Structures, Vol. 25, No. 4, 2003, pp. 405-417 https://doi.org/10.1016/S0141-0296(02)00182-7
12. Dyke, S. J., Turan, G., Caicedo, J. M., Bergman, L. A., and Hague, S., 'Phase I Benchmark Control Problem for Seismic Response of Cable-Stayed Bridges,' Journal of Structural Engineering, ASCE, Vol. 129, No.7, 2003, pp. 857-871 https://doi.org/10.1061/(ASCE)0733-9445(2003)129:7(857)
13. Skelton, R. E., Dynamic systems control: Linear systems analysis and synthesis, New York: Wiley, 1988
14. Stengel, R. F., Stochastic optimal control: Theory and application, John Wiley and Sons, Inc., New York, 1986
15. Nishitani, A. and Inoue, Y., 'Overview of the Application of Active/Semiactive Control to Building Structures in Japan,' Earthquake Engineering and Structural Dynamics, Vol. 30, 2001, pp. 1565-1574 https://doi.org/10.1002/eqe.81
16. Dyke, S. J., Spencer, Jr. B. F., Sain, M. K., and Carlson, J. D., 'Modeling and Control of Magnetorheological Dampers for Seismic Response,' Smart Materials and Structures, Vol. 5, 1996, pp. 565-575 https://doi.org/10.1088/0964-1726/5/5/006
17. Dyke, S. J. and Spencer, Jr. B. F., 'A Comparison of Semi-Active Control Strategies for the MR Damper,' Proceedings of the lASTED International Conference on Intelligent Information Systems, The Bahamas, 1997
18. Turan, G., 'Active control of a cable-stayed bridge against earthquake excitations,' Ph.D. Dissertation, Department of Civil Engineering, University of Illinois at Urbana-Champaign, 2001