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214 matrix of modal control. This is one of the important benefits of the proposed modal control scheme. The numerical results show that the motion of the structure was effectively suppressed by merely controlling a few lowest modes, although resulting responses varied greatly depending on the choice of measurements available and weightings. The modal controller A and V achieved significant reductions in the responses. The modal controller Ayj, A J2 and V J3 achieve reductions (39%, 30%, 30%) in evaluation criteria Ji, Jo and */3, respectively, resulting in the lowest values of all cases considered here. The modal controller AJT and VJT fail to achieve any lowest value of evaluation criteria, but have competitive performance in all evaluation criteria. Based on these results, the proposed modal control scheme is found to be suited for use with MR dampers in a multi-input control system. Further studies are underwav to examine the influence of the number of controlled modes on the control performance. ACKNOWLEDGEMENTS This research was supported by the National Research Laboratory Grant(No. : 2000-N-NL-01-C-251) in Korea. The financial support is gratefully acknowledged. REFERENCES Brogan, W.L. (1991). Modern Control Theory, Prentice Hall, Englewood Cliffs, New Jersey. Dyke, SJL, Spencer Jr., B.F., Sain, M.K. and Carlson, J.D. (1996). "Modeling and Control of Magnetorheological Dampers for Seismic Response Reduction," Smart Materials and Structures, Vol. 5, pp. 565-575. Inaudi, J.A. (1997). "Modulated Homogeneous Friction: A Semi-active Damping Strategy," Earthquake Engineering and Structural Dynamics, Vol. 26, No. 3, pp. 361. Jansen, L.M. and Dyke, SJ. (2000). "Semi-active Control Strategies for MR Dampers: Comparative Study," Journal of Engineering Mechanics, Vol. 126, No. 8, pp. 795-803. Leitmann, G. (1994). "Semiactive Control for Vibration Attenuation," J. of Intelligent Material Systems and Structures, Vol. 5 September, pp. 841-846. McClamroch, N.H. and Gavin, H.P. (1995). "Closed Loop Structural Control Using Electrorheological Dampers," Proc. oftheAmer. Ctrl. Conf. 9 Seattle, Washington, pp. 4173-77. Meirovitch, L. (1990). "Dynamics and Control of Structures," John Wiley & Sons. Sack, R.L., Kuo, C.C., Wu, H.C., Liu, L and Patten, W.N. (1994). "Seismic Motion Control via Semiactive Hydraulic Actuators." Proc. of the U.S. Fifth National Conference on Earthquake Engineering, Chicago, Illinois, Vol. 2, pp, 311-320. Spencer Jr., B.F., Dyke, S. J., Sain, M. K., and Carlson, J. D. (1997). "Phenomenological Model off Magnetorheological damper," Journal ofEngrg. Mech., ASCE, 123(3), pp. 230-238.
Proceedings of the Intel-national Conference on Advances and New Challenges in Earthquake Engineering Research, Hong Kong Volume EFFECTIVENESS OF SMART BASE ISOLATION SYSTEM WITH MR DAMPERS IN PROTECTING STRUCTURES IN NEAR-FAULT EARTHQUAKES Satish Nagarajaiah 1 , Sanjay Sahasrabudhe 2 and Yuqing Mao 2 1.Associate Professor, Civil & Env. Eng. , Rice University, Houston, TX 2 Engineer, McDermott, Houston, TX, Formerly, Graduate Research Assistant, Rice University Abstract This paper presents an analytical study of smart base isolated structures with vanable MR dampers, which extends the results of prior analytical and experimental studies by the authors. New analytical models of the nonlinear base isolated structures with MR dampers are developed. A Lyapunov based controller is developed and used to perform simulations. Numerical simulations and parametric studies are performed using several near-fault ground motions. The computed results are verified using shake table test results of scaled base isolated structural model with MR dampers. It is demonstrated that base isolated structures with MR dampers are more effective than base isolated structures with passive nonlinear dampers, in reducing the response in wide range of near-fault earthquakes. Introduction Base isolation systems are effective in protecting structures in strong earthquakes. Recent studies have shown that base isolated structures tend to have larger base displacements in near-fault long period earthquakes. This may lead to large isolation gap or in cases—with insufficient isolation gap—pounding against the retaining wall of the building, and damage to the superstructure. Nonlinear passive dampers have been implemented in base isolated buildings to counter some of the effects of near-fault earthquakes (Taylor et al. 2001). Although supplemental nonlinear passive dampers can limit base displacements, the isolation forces, superstructure drifts and accelerations will be higher. Several researchers have recently studied the capability of Magneto-rheological (MR) dampers and other variable dampers in effectively countering such limitations (Gavin et al. 2001, Madden et al. 2000, Nagarajaiah et al. 2000, Spencer et al. 2000, Yang et al 2002, and Yoshika et al. 2002). MR clampers, which can be used to vary the nonlinear damping in the isolation systems, can reduce base displacements in near-fault earthquakes, further than passive nonlinear dampers, while maintaining the same or lower level of isolation forces, superstructure drifts and accelerations, as compared to passive nonlinear dampers (Sahasrabudhe et al. 2000,2001). Spencer et al. (2000) and Yoshioka et al (2002) have shown the effectiveness of base isolated structures with MR dampers in both moderate/strong and in near/far-fault earthquakes by analytical and experimental studies. This paper presents an analytical study of smart base isolated structures with variable MR dampers, which extends the results of prior analytical and experimental studies by the authors (Sahasrabudhe et al. 2000, 2001). It is demonstrated that base isolated structures with MR dampers are more effective than base isolated structures with passive nonlinear clampers, in reducing the response in wide range of near-fault earthquakes. Analytical Model of Smart Base Isolated Structure with MR Dampers The equations of motion for the smart base isolated structure shown in Figure 1 are as follows M C U C + C C U C + K C U C + F c = B E u s (1) c f U \ ("
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Proceedings of the International Co
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vw:. PREFACE Dunng a time when eart
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OPENING ADDRESS By Prof. Yuchen Liu
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Vll scientific support in our call
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IX INTERNATIONAL ADVISORY COMMITTEE
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XI Engineering Seismology and Geote
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Xlll Progress in the Seismic Design
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XV Crustal Deformation Measurement
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Legal Impediments There are many im
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expectation of (i) expanding the fr
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10 Some applications of wireless te
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12 Smart Materials Smart materials,
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14 research and education in a mult
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19 On September 16, 1994, buildings
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21 Some people were injured while t
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23 tallest buildings in Hong Kong w
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25 Figure 12. Tsim Sha Tsui East an
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27 OTHER ONGOING WORKS Soil-pile-st
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29 Figure 18. The pounding experime
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31 ACKNOWLEDGMENTS The writers are
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35 Table 1. Records Used in the Dev
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37 Date 8/19/1976 10/5/1977 12/16/1
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39 (2) Here Y is the ground motion
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41 1 2 3 4567810 20 3040 SO 100 200
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43 of the resultant horizontal comp
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45 200 006 005 004 003 002 Rock, Mw
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47 en o_ KOCAELI DATA (Random Hor C
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Atkinson G.M., Boore D.M., Some Com
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52 BACKGROUND AND SCOPES In order t
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configurations of cylinder, and it
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l 56 X xT / ^ V^—Ê-^/i / X\ - yX
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58 59-74 (in Japanese) [7] ISHIKAWA
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60 accuracy and efficiency, have no
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62 f •c J — c. p «3 no Fig. 2
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64 VARIOUS TESTS AND DISSEMINATION
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66 response.. The post-earthquake i
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71 with the potential for self-diag
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73 Semi-active Hydraulic (SHD) Cont
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75 Table 1 Buildings currently unde
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77 and the inside of the damper cyl
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79 Figure 16. MR damper installatio
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81 sensors. New algorithms must be
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83 Kobon T. (1998). Mission and per
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87 for a period range less than 3.0
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89 tens or more than a hundred acce
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91 In order to validate the conclus
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93 Distance (km) """"--Âcc. (g) Ma
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95 CONCLUSION In this paper the imp
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ENGINEERING SEISMOLOGY AND GEOTECHN
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100 analyses. This paper reviews th
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102 A comparison of spectral amplit
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104 the high speed with which FFT c
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106 8. Gold, B. and C.M. Rader (197
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108 Displacement Curves", Dept. of
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I 000,000 100,000 Number of uniform
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Response and Fourier Spectra of Dig
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114 10 3 10 2 r | I lll| I | I | I
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116 analysis. Other techniques incl
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It has been found that G max applie
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120 PALEOLIQUEFACTION STUDIES IN ME
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Jardine, R.J., Potts, D.M., StJohn,
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124 has received more attention. In
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126 and log A tQ (/) is the mean so
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128 O 10 s Frequency (Hz) Frequency
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130 geometrical coefficient is near
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132 optimizing method in many engin
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134 Type-2 Fig.5 Three dimensional
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136 plane plane sliding x-z section
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141 1. System Definition define sys
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143 f«l-.J WJjfc >. « Relations -
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145 DS-5 Response Simulation across
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147 CM 1 CM 2 CM 3 CM-4 CM-5 CM-6 H
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151 Number of Pixels (Frequency) Th
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153 Red: possible impacted areas Gr
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155 Low reliability -(water-reflect
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Modem or Router Dial-up ISP The Int
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from observed images Fig 5 shows th
Page 179 and 180: 163 Picked up building from image p
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Page 196 and 197: 180 MAX STORY DUCTILITY vs NORM. ST
Page 201 and 202: 185 Decision Making Support Tool' U
Page 205 and 206: 189 31 Array Liujiaxia Reservoir Ar
Page 207 and 208: 191 IV STATION YM kCED INTERVALS OF
Page 209 and 210: 193 at different stations, the diff
Page 213 and 214: 197 PROBLEMS AND CHALLENGES Earthqu
Page 215 and 216: 199 Database s*n/ar_- ^ " Applicati
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Page 219: SMART MATERIALS AND SMART STRUCTURE
Page 225 and 226: 209 vector of measured control forc
Page 227 and 228: 211 To examine the effect of the co
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Page 233 and 234: 217 where gjî = g(X fcTl , F^+ît
Page 235 and 236: 219 3 360 Deg. Fault Normal (Jan. 1
Page 237 and 238: 221 Earthquake Sylmar 90 Sylinar 90
Page 241 and 242: 225 0.6965, and 0.7094 Hz, which ar
Page 243 and 244: 227 Two displacement sensors are po
Page 245 and 246: 229 14% to 45% (under El Centre ear
Page 249 and 250: 233 g ^ w (4) Notice that the stabi
Page 251 and 252: 235 modes. An energy drop will be o
Page 253 and 254: 237 PPF controller. The second mode
Page 257 and 258: 241 In order to determine the appar
Page 259 and 260: 243 RESULTS AND DISCUSSIONS Figure
Page 261 and 262: 245 100 150 200 250 300 Magnetic Fl
Page 265 and 266: 249 WOLFE, MASRI, CAFFREY Synthetic
Page 267 and 268: 251 WOLFE, MASRI, CAFFREY Transform
Page 269 and 270: 253 WOLFE MASRI,CAFFREY in parallel
Page 271: STRUCTURAL ANALYSIS AND DESIGN
Page 274 and 275: 258 separating the above three effe
Page 276 and 277: 260 200 300 400 SHAKE Computed RSD^
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264 6. ACKNOWLEDGEMENTS The work de
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266 The objectives of this paper pr
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268 The comparison between abovemen
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270 determine the span of the state
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the assumption of the bi-linear for
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274 There are several outstanding e
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276 buildings with different concre
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278 160,000 - 140,000 _^ d Concrete
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280 responded in a fairly similar m
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282 CONCLUSIONS In this paper, the
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284 Li B, Park, R. and Tanaka, H. (
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For simplicity, a linear distributi
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equation can be re- written as: 288
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290 DESIGN BASE SHEAR Equating the
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292 by using the computer program S
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294 mutation. Elitist strategy mean
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296 2.3 Premature Judgment and Comb
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298 (3) F 3 : De Jone's F 5 3 (Shek
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300 3.3 Test Conclusions From the t
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30; excitation. Also, the software
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304 concrete frames as documented i
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30€ NEURAL NETWORKS Development I
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308 ACKNOWLEDGEMENTS The research r
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310 In order to ensure the entire s
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312 Examples of Seismic Design In K
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314 earthquake load can be reduced
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Proceedings of the Intel national C
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319 broken. Therefore, joint elemen
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321 the highest probability to get
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325 DESIGN SPECIFICATIONS Overview
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327 Strength Degradation The streng
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I 329 file £dit Vww Select Constru
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333 (1) (2) Where f t and _/£ are
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335 JL dalt (10) Where Solution of
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337 Fig.9 Distribution of first pri
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341 DISPLACMENT-BASED NSF In this p
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343 Define the displacement of the
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345 EXAMPLE The nonlinear static an
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347 REFERENCE Code for seismic desi
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350 including Hong Kong are conside
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352 structural engineers. Although
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354 4) Structural characteristics R
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356 maintain economy of design but
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358 R C3&OC11 L8C34 USC3 •••
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363 DISPLACEMENT CALCULATION FOR GR
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365 As shown in the figure, a model
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367 history of a design earthquake
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371 reflects the structure's useful
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373 have a membership degree betwee
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375 of initialization of structure,
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377 REFERENCE Zadeh, L A (1965), "F
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.0,(r+l,,)] (0 + A (3) 383 -l.y)] (
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385 The first example is come from
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387 REFERENCES Leroueil, S. (2001).
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391 maximum friction force and ther
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393 the stiffness of the bracing an
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395 splacemen (m) Bared —Braced/D
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399 Figure 1: Two-surface Model Def
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401 time, one must integrate over t
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403 CONCLUSIONS In the previous sec
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407 Response Control by Magneto-Rhe
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409 s e a ooo j| soo y 0 c l83Hz ,5
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411 *fU O A 20 7 HA I , 2 4A .'.-%-
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415 Wind Velocity (t J Relative Dis
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417 Fig. 5 4ttractor (time lag=l) F
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419 concluded that the real time re
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422 (LQR/LQG), H M and the instanta
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424 damping ratio provided by the c
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426 by Eqn. 2.9 and Eqn. 2.12, resp
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428 Fig.5.4 shows the comparison of
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Innovation is driving control devic
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432 STRUCTURAL ENERGY DURING VIBRAT
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434 Equilibrium Price of Power With
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436 CONCLUSION The scope of this re
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438 The effectiveness of the seismi
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440 anti-symmetnc mode excited by t
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442 Base Isolation System The base
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444 each member along or adjacent t
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446 2 PROJECT PARTICIPANTS Concerni
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448 3.1.2 Investigations at Seyhan
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450 Fig. 4.2: principle drawing of
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452 no TMD — TMD with optimal tun
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454 In this paper, a stochastic opt
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456 The dynamical programming equat
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458 control strategy. Model reducti
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460 (AMDs) and the proposed control
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465 Specimen 1 Specimen 1 represent
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467 increased the beam moment stren
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469 3 4@8 ~T / C 4 #5 #3 stirrups 8
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473 Phase 2: The sliding of the bot
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475 4.2 Effect of Coefficient of Fr
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477 -ZETA=Q 05 -ZETA=010 -ZETA=015
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479 031 en 03 0029 P |Q 28 ~*—MR=
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482 stiffness or coefficient of vis
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484 solved for the Hamilton Jacobi-
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486 posed to be the accelerations o
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488 vlaxacccleiation [my O O O O
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490 INTRODUCTION In recent years, t
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492 Since earthquake motion has bee
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494 confirmed in the X direction. B
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496 yielding metallic dampers, and
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498 where the coefficients a m and
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500 modal damping ratio of 2% in ea
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502 CONCLUDING REMARKS The paper re
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504 semi-active and hybrid control
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506 Iiz2i(t)l
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508 defined as 114 - [ J* [•] 2 d
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Spencer, B.F., Jr. and Sain, M.K. (
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512 with the rapid success of seism
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Figure 3 summarizes the static push
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CONCLUSIONS 516 This paper presents
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518 1 OS h : 0 6 5 5 04 Transverse
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520 TABLE 1 REPRESENTATIVE MULTISTO
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522 obtained by simply averaging a
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524 levels of peak ground accelerat
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526 8 CONCLUSIONS This paper gives
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531 350.6m 142.7m .0130') i (468')
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533 cation corresponds to a node of
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535 listed separately. Vertical mod
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539 in which H = [H(t l ), H(t 2 ),
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541 identification results of struc
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543 history to be polluted. In the
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548 environment constraints and the
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550 where F is the fundamental matr
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552 drift ratio was determined as Y
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554 were observed in the vision-sys
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556 The most well-known Bayesian so
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558 achieved by the EKF estimates I
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560 0 2 4 5 3 10 12 14 16 18 20 0 2
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562 CONCLUSION In this study, the r
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564 Figure 1 - Prototype wireless s
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566 will vary from that of the ARX
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568 A 11 25" 11 25" 1 T 1 11 25* !
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570 CONCLUSION The realization of a
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572 the structural response and ret
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574 The ratios of base shear at dif
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576 SECTION A-A COLUMN DETAIL AT TO
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578 Stress Strain Fig. 6 Superelast
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580 Genetic Algorithm(GA) and the M
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582 IDENTIFICATION ALGORITHM State
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584 the simulated structural respon
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586 GA-MCF, the number of particles
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588 instrumentation to monitor and
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590 If we compare this peak value w
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592 2.3 Sampling rate Structural mo
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594 Any remote station that has the
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596 or receives environmental infor
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598 Comparisons of Proposed E-Monit
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600 LCD display Earthquake Warning
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605 Kishwaukee River Bridge consist
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607 the table, the monthly maximum
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609 3.2 L VDTData Analysis LVDT sen
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structural response energy with fre
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615 Table 1: Fundamental natural fr
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617 JUSTS rs s." WUUR. 4 20O2 IS 44
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1-1 INDEX OF CONTRIBUTORS Volumes I
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Ths OOO F X ^s dje foe return 01 ê
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