Geoscience Reference
In-Depth Information
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Fig. 5.30. CEA-CESTA pneumatic shock actuator
shown. A Mexico earthquake record was simulated at 50g and a very good agreement is
observed between theacceleration recorded on the tableand the specified values.
5.5. RECENT ADVANCES INEARTHQUAKE ACTUATION WORLDWIDE
The most widespread shakers installed on geotechnical centrifuges are indeed large1D
shaking tables using servo-hydraulic actuators. Some 2D shakers already exist
(Figure 5.32) or are being developed in Honk-Kong, in USA (Davis and RPI), in
Korea (Daejon), and in England (Cambridge). There is a definite need to understand
the interplay of the vertical shaking effects along with the horizontal shaking. Europe
needs to engage in this development and develop a 2D actuation facility. Currently,
efforts areunderway at Cambridge in this direction.
AgreatstrideforwardisbeingtakenthankstotheNorthAmericanproject“NEES”(Net-
workforEarthquakeEngineeringSimulation),launchedinOctober2000.MorethanUS$
9millionofinvestmentallowedupgradingtheUCDavis(UCD)andRPI(NewYork)cen-
trifuges.IntheUCDfacility,upgradesincludethe2D(horizontalandvertical)shakerand
a robot (Figure 5.33). Seismic and electrical tomography and 3D image processing will
also be introduced. The data obtained during earthquake centrifuge tests are transmitted
