This research demonstrates that appropriately constructed bench-scale models can be used to study important aspects of full-scale structural control implementations, including: control-structure interaction, actuator and sensor dynamics, actuator saturation effects, limited availability of sensors, output feedback design, digital control implementation, control spillover, etc. The active control experiment considered herein is shown to be an effective tool for familiarizing students and pratitioners with control system design and the associated challenges.
Battaini, M., Yang, G., Spencer Jr., B.F., "Bench-Scale Experiment for Structural Control," Journal of Engineering Mechanics, ASCE, 126(2), pp. 140-148, 2000.
Two widely used methods
for mitigating structural vibration due to natural hazards such as wind and
earthquakes are active mass driver / tuned mass damper systems and base isolation.
Four Java-powered simulations are provided here to explore
some of the issues in design of these structural control systems. These programs
can calculate and animate the structural responses of a simple building model
under the El Centro, Hachinohe, Northridge and Kobe earthquakes. Furthermore,
transfer functions of the uncontrolled and controlled systems may be viewed.
You can vary the structure and control/isolation parameters and do "what if"
studies to understand the effects of varying the control/isolation systems.
Note that either Netscape 4.0 or MS Explorer 4.0 is required to run the Simulators.
Depending on the speed of your connection, the Simulators may take a minute
or so to load. After loaded, network speed will not affect simulator performance.
Partial funding of the development of these simulators was provided by the Multidisciplinary
Center for Earthquake Engineering Research.
Y. Gao, G. Yang, B.F. Spencer, Jr., and G.C. Lee, "Java-Powered Virtual Laboratories for Earthquake Engineering Education," MCEER Research Progress and Accomplishments 2003-2004, MCEER, pp. 187-203, 2004 (Also accepted by the Journal of Computer Applications in Engineering Education).
One of the exciting new application areas for feedback system design has to do with the protection of civil engineering structures from dynamic loadings such as strong earthquakes, high wind, extreme waves, heavy traffic, and highway loading. Buildings and other physical structures, including highway infrastructures, have traditionally relied on their strength and ability to dissipate energy to survive under severe dynamic loading. In recent years, worldwide attention has been directed toward the use of control and automation to mitigate the effects of these dynamic loads on these structures. Active systems are also used temporarily in construction of bridges or large span structures (e.g., lifelines, roofs) where no other means can provide adequate protection. To date, there have been more than 44 buildings and 14 bridges (during erection) that have employed feedback control strategies in full-scale implementations.
El Centro earthquake signal: North-south component recorded at Imperial Valley Irrigation District substation in El Centro, California, during the Imperial Valley, California earthquake of May, 18, 1940. The magnitude is 7.1 and the maximum ground acceleration is 0.3495g.
Takochi-oki (Hachinohe) earthquake signal: North-south component recorded at Hachinohe City during the Takochi-oki earthquake of May, 16, 1968. The magnitude is 7.9 and the maximum ground acceleration is 0.2294g.
Northridge earthquake signal: North-south component recorded at Sylmar County Hospital parking lot in Sylmar, California, during the Northridge, California earthquake of Jan. 17, 1994. The magnitude is 6.8 and the maximum ground acceleration is 0.8428g.
Hyogo-ken Nanbu (Kobe) earthquake signal: North-south component recorded at Kobe Japanese Meteorological Agency (JMA) station during the Hyogo-ken Nanbu (Kobe) earthquake of Jan. 17, 1995. The magnitude is 7.2 and the maximum ground acceleration is 0.8337g.
The results from Active Bracing and Active Mass Driver (AMD) experiments performed at the SDC/EEL have been documented in two videos. The videos also show the SDC/EEL facilities and equipment. Two short clips from the video of the active mass driver experiment are available by clicking below. Requests for copies of the complete video may be directed to Prof. B.F. Spencer, Jr. at: bfs@uiuc.edu
Video Clip of the AMD Experiment - MPEG, 1.3
MBThis video clip demonstrates the effectiveness of the Active Mass Driver System for Structural Control through use of a split screen display. The top image shows the uncontrolled response, while the bottom image displays the response to the same ground excitation, but this time with control on.
Close-up of the AMD in Action - MPEG, 1.0
MBThis video clip shows a close-up of the AMD operating in the Control On state.
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