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Earthquake Engineering Research - HKU Libraries - The University ...

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427<br />

Shown in Fig. 5.3 is the ratio of active devices dissipated energy to the structural dissipated energy by<br />

three control strategies under El Centro earthquakes. In this figure, the upper lines inply that the larger<br />

additive damping ratio £ a . We can observed from the figure that the larger f a can dissipate more<br />

earthquake input energy compared to the dissipated energy by structure itself, and the latter are<br />

comprised of viscous damping dissipated energy and hysteretic behavior dissipated energy. However,<br />

the trend will weaken in the situation of larger intensity earthquakes.<br />

05 10 15 20 25 30<br />

(a) the l sr mterstory drift<br />

10 15 20 25 30<br />

(b) the 5 th tnterstory drift<br />

Fig. 5.1 <strong>The</strong> interstory drifts by three control strategies under El Centro earthquake<br />

1 0-,<br />

08-<br />

06-<br />

04-<br />

02-<br />

00-<br />

intereity<br />

Fig.5.2 <strong>The</strong> 1st story damage under<br />

Northridge earthquake<br />

Fig. 5 3 <strong>The</strong> ratio of dissipated energy<br />

under El Centro earthquake<br />

5.2 <strong>The</strong> Control Force with the State Estimation by EKF<br />

Consider the same model above, however, only the fifth floor displacement is observed and other<br />

states will be estimated by EKF and the Kalman filter, respectively, to implement the active control<br />

strategy in this case.<br />

full state feedback<br />

the Kdlnan filter estimated<br />

state feedback<br />

— full state feedback<br />

O the EKF estimated<br />

state feedback<br />

0 10 20 30 40 50 0 10 20 30 40 50<br />

(a)<br />

(b)<br />

Fig.5.4 Comparison of the 5 th relative displacement response (MC<br />

controller , £ a = 0.08, with the intensity =2,0) of three types of state feedback cases<br />

under ElCentro earthquake

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