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450 Fig. 4.2: principle drawing of a semi-active tuned mass damper The output of the MR damper will be controlled by a special algorithm which aims at minimising the bridge displacements. Based on a set of continuously measured system state variables during a dynamic excitation, the algorithm evaluates an optimal force which will be approximated by varying the strength of the magnetic field. The maximum current supply for the MR device will be only a few amperes and therefore can be realized by a small battery and a solar panel. 4.2.1 Numerical analysis and results The analysis of the footbridge was carried out using a simplified structural model (2 DOF system, representing the corresponding eigenform and the TMD) and the non-linear numerical model for the simulation of the MR damper. The investigations were performed implementing a passive and a semiactive TMD. The dynamic loading induced by a pedestrian was assumed by a stationary harmonic load (4.2.1) at maximum of the corresponding eigenform. The amplitudes A, represent dynamic components of a walking, running or jumping pedestrian (G = 1,0 kN) with corresponding phase angle 0 t . For running, the sum of these amplification factors can reach about 2.5 times the static load. As it is commonly known that pedestrians synchronize their movement due to the frequency of the bridge, the angular frequency (Ob is assumed to be the one of the corresponding bridge eigenform. In a first study the dynamic response of the footbridge in terms of its displacement (at maximum of the corresponding eigenform) without TMD, with a passive TMD in the optimal configuration and with a semi-active TMD with properties of the optimal passive one was investigated. As the dynamic behaviour of the footbridge with both types of TMD (optimal passive and semi-active) are more or less coincident, it can be concluded that no improvement (but also no deterioration) is obtained by implementing a semi-active damper - in case the TMD already exposes optimal properties
451 due to the Den Hartog criteria. The effectiveness of the TMD could be observed as the maximum displacements are reduced to 1mm in comparison to the undamped motion with maximum value of about 7mm. When performing a numerical modal analysis of a structure, natural frequencies higher than the real ones are obtained in general, as the masses and material stiffness are assumed on the save side (usually the mass is overestimated and the material stiffness is underestimated). These assumptions finally result in calculated frequencies to be about 10-20% higher than the real occurring frequencies. Experimental testing on the footbridge always is recommended to optimize the TMD. Nevertheless, in order to show the influence of higher real system stiffness than the assumed one (resulting in a nonoptimal configuration of the TMD), the dynamic response of the bridge is shown in Fig. 4.3 for a running pedestrian. -no TWO ~TMD with optimal tuned passive damper 0004 0005 ""TMD with subopttmal tuned passve damper -TMD with suboptimal tuned semi-active damper Fig. 4.3 Bridge response with non-optimal TMD properties (stiffness variation) It can be observed that in case of a non-optimal tuned TMD, the amplitudes are app. 35% higher than in case of optimal tuning. In case of a non-optimal tuned semi-active TMD, the maximum displacements (and accelerations) do not exceed the values of the optimal tuned passive TMD. This shows the excellent performance of a semi-active controlled TMD. Due to presence of live loads on the bridge deck, the mass of the structure may significantly vary which again results in a non-optimal configuration of the TMD. In case the total mass of the bridge is very high, only little influence on the natural frequency has to be expected, as it varies proportional to the square root of the mass. However, in case of the footbridge in Forchheim, the live loads may increase the total bridge mass by a factor of 2. Thus, the passive TMD cannot be tuned optimal for different load cases. In order to show this effect, the bridge mass of the simplified model was increased by a factor 1.6 (taking into account that the corresponding eigenform only represents a part of the total mass). The resulting response of the bridge is shown in Fig. 4.4 for the undamped case as well as for the cases with a passive TMD and with a semi-active TMD.
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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
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163 Picked up building from image p
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167 evaluated by Seed's approximate
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169 R(z,N)is reached to 1 or more,
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171 subsoil and combined with the n
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174 defined target. Performance-bas
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176 (probability of being in or exc
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178 start to dominate the hazard at
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180 MAX STORY DUCTILITY vs NORM. ST
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185 Decision Making Support Tool' U
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189 31 Array Liujiaxia Reservoir Ar
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191 IV STATION YM kCED INTERVALS OF
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193 at different stations, the diff
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197 PROBLEMS AND CHALLENGES Earthqu
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199 Database s*n/ar_- ^ " Applicati
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201 o Fig. 7 VRML authoring - model
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SMART MATERIALS AND SMART STRUCTURE
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209 vector of measured control forc
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211 To examine the effect of the co
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213 from Fig. 2, we can get the res
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Proceedings of the Intel-national C
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217 where gjî = g(X fcTl , F^+ît
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219 3 360 Deg. Fault Normal (Jan. 1
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221 Earthquake Sylmar 90 Sylinar 90
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225 0.6965, and 0.7094 Hz, which ar
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227 Two displacement sensors are po
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229 14% to 45% (under El Centre ear
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233 g ^ w (4) Notice that the stabi
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235 modes. An energy drop will be o
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237 PPF controller. The second mode
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241 In order to determine the appar
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243 RESULTS AND DISCUSSIONS Figure
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245 100 150 200 250 300 Magnetic Fl
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249 WOLFE, MASRI, CAFFREY Synthetic
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251 WOLFE, MASRI, CAFFREY Transform
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253 WOLFE MASRI,CAFFREY in parallel
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STRUCTURAL ANALYSIS AND DESIGN
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258 separating the above three effe
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260 200 300 400 SHAKE Computed RSD^
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262 where H b is the building heigh
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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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Page 415 and 416: 399 Figure 1: Two-surface Model Def
Page 417 and 418: 401 time, one must integrate over t
Page 419 and 420: 403 CONCLUSIONS In the previous sec
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Page 423 and 424: 407 Response Control by Magneto-Rhe
Page 425 and 426: 409 s e a ooo j| soo y 0 c l83Hz ,5
Page 427 and 428: 411 *fU O A 20 7 HA I , 2 4A .'.-%-
Page 431 and 432: 415 Wind Velocity (t J Relative Dis
Page 433 and 434: 417 Fig. 5 4ttractor (time lag=l) F
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Page 438 and 439: 422 (LQR/LQG), H M and the instanta
Page 440 and 441: 424 damping ratio provided by the c
Page 442 and 443: 426 by Eqn. 2.9 and Eqn. 2.12, resp
Page 444 and 445: 428 Fig.5.4 shows the comparison of
Page 446 and 447: Innovation is driving control devic
Page 448 and 449: 432 STRUCTURAL ENERGY DURING VIBRAT
Page 450 and 451: 434 Equilibrium Price of Power With
Page 452 and 453: 436 CONCLUSION The scope of this re
Page 454 and 455: 438 The effectiveness of the seismi
Page 456 and 457: 440 anti-symmetnc mode excited by t
Page 458 and 459: 442 Base Isolation System The base
Page 460 and 461: 444 each member along or adjacent t
Page 462 and 463: 446 2 PROJECT PARTICIPANTS Concerni
Page 464 and 465: 448 3.1.2 Investigations at Seyhan
Page 468 and 469: 452 no TMD — TMD with optimal tun
Page 470 and 471: 454 In this paper, a stochastic opt
Page 472 and 473: 456 The dynamical programming equat
Page 474 and 475: 458 control strategy. Model reducti
Page 476 and 477: 460 (AMDs) and the proposed control
Page 481 and 482: 465 Specimen 1 Specimen 1 represent
Page 483 and 484: 467 increased the beam moment stren
Page 485 and 486: 469 3 4@8 ~T / C 4 #5 #3 stirrups 8
Page 489 and 490: 473 Phase 2: The sliding of the bot
Page 491 and 492: 475 4.2 Effect of Coefficient of Fr
Page 493 and 494: 477 -ZETA=Q 05 -ZETA=010 -ZETA=015
Page 495: 479 031 en 03 0029 P |Q 28 ~*—MR=
Page 498 and 499: 482 stiffness or coefficient of vis
Page 500 and 501: 484 solved for the Hamilton Jacobi-
Page 502 and 503: 486 posed to be the accelerations o
Page 504 and 505: 488 vlaxacccleiation [my O O O O
Page 506 and 507: 490 INTRODUCTION In recent years, t
Page 508 and 509: 492 Since earthquake motion has bee
Page 510 and 511: 494 confirmed in the X direction. B
Page 512 and 513: 496 yielding metallic dampers, and
Page 514 and 515: 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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