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Shaking
Table System for Geotechnical Centrifuge
The Need
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Because of the
increasing constructions of large-scaled and important structures on soft grounds
especially in bay area development, it has become very necessary to investigate the
seismic ground behavior. One effective method of studying such behavior is to conduct
shaking table tests under a centrifugal field using a model specified from the actual
structure in accordance with the similarity law, so as to allow economic evaluation of
alternative designs, investigation of complex problem areas, and validation of numerical
methods with instrumented physical models. |
Shaking table system |
The Technology
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The
shaking table system for geotechnical centrifuge, which can simulate sinusoidal and real
seismic waves under a centrifugal force of 50 times earth gravity, is capable of providing
significant data for the seismic design of structures. The shaking table can accommodate
test specimens up to 250kg under 50G condition, so it can be used to perform various types
of ground shaking tests. Because the maximum excitation acceleration of the shaking table
is 25G (i.e. 500 Gal in full scale prototype), it can simulate the response of ground
during large earthquakes.
The available frequency range of the system is
from 25 to 350Hz (corresponding prototype frequency is 0.5~7Hz), which covers the
predominant frequency range of real earthquakes. The data acquisition system can
simultaneously measure 48 channels of signals including acceleration, displacement, pore
water pressure and earth pressure, etc. |
Principle of Centrifuge Modeling Test |
The Benefits
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This technology can be applied following
fields: 1) Investigation on the dynamic soil-structure(such as bridge foundation, tunnel,
etc.) interaction. 2) Simulation of the response of liquefied ground. 3) Verification of
liquefaction-resistant construction method. 4) Verification of the seismic stability of
soil-structures. |
Status
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Direct application to specific engineering
design historically has been reserved for large projects, which justify the time and
expense involved. These have included, for example, offshore foundation design in the oil
industry; large span bridge pier foundation design; seismic and non-seismic design of
embankment dams; and seismic design of bridge foundations and waste disposal facilities.
However, the frequency with which it is used by large design-construct firms
internationally is increasing, especially in Japan. Together these trends point to its
increased use in engineering design of difficult, unusual, or extreme geotechnical
engineering design. |
Barriers
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Geotechnical centrifuge modeling is a highly
specialized laboratory based technique. As such, it suffers from the traditional obstacles
to moving research results into practice. For the engineer-contractor, this means
developing an appreciation of the potential advantages derived from smarter geotechnical
engineering, and being able to see different scenarios played out before construction; the
visual nature of the modeling, enhanced by collection of soil and structural response
data, however, makes the investment very attractive. For the researcher, this will require
increased sensitivity and understanding of the practical needs of real construction, in
terms of economics, response time, and the appropriateness of the end product delivered to
the engineer-contractor. |
Points of Contact
- Dr. Naoto Ohbo <ohbo@katri.kajima.co.jp>,
Kajima Technical Research Institute
Phone: 81-424-89-7296 Fax: 81-424-89-7116.
- Dr. Deborah J. Goodings, Director of the UMCP Center for
Geotechnical Centrifuge Modeling, <goodings@eng.umd.edu>,
Phone: 301-405-1960
Fax:301-405-2585.
References
- Kajima Technical Research Institute
- Center for Geotechnical Centrifuges Modeling, <http://www.cee.umd.edu/centrifuge/>
- U.S. Army Centrifuge Research Center, <http://www.wes.army.mil/centrifuge/index.html>
Disclaimer Statement
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Neither the Construction
Industry Institute nor Purdue University in any way endorses this
technology or represents
that the information presented can be relied upon without further investigation. |
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