|Publications: SRL: EduQuakes|
Editor’s Note: This is the second of a two-part Eduquakes series on educational shake tables. In Seismological Research Letters 78(3), Eduquakes provided a brief survey of low-end shake tables and activities; here Shirley Dyke and co-authors describe an ongoing effort to allow wide access (via the Internet) to more sophisticated shake tables. These bench-top tables are capable of matching realistic earthquake ground motion and would enhance any seismology class. For example, students could first calculate the expected waveforms from an earthquake and then test the effects on a model building, thereby providing a system-level “rupture-to-rafters” understanding of earthquakes and their effects. Although developed primarily for earthquake engineering, these tools are potentially useful to a much wider audience.
Bench-scale shake tables are an engaging tool for educating students at all levels about the importance of earthquake engineering. Shake tables allow for classroom demonstrations and hands-on experimentation regarding structural response to earthquake ground motions. Demonstrations for K–12 students allow students to gain an understanding of earthquake motions and how structures can be designed or retrofitted to better withstand seismic motions. At more advanced levels, undergraduate and graduate students can conduct experiments to test their knowledge of fundamental concepts. Students may also build or modify scaled structural models to experiment with their own innovations and may also gain experience with modern sensors. While theoretical and analytical discussions are necessary, hands-on experiments are quite effective for demonstrating basic concepts in structural dynamics and earthquake engineering and nicely supplement more traditional educational methods.
The University Consortium on Instructional Shake Tables (UCIST) was developed by Shirley Dyke in 1998 to enhance undergraduate and graduate education in earthquake engineering (see http://ucist.cive.wustl.edu/). This consortium, headquartered at Washington University in St. Louis, was initially a cooperative educational effort among 23 universities associated with the three U.S. national earthquake centers—the Pacific Earthquake Engineering Research Center (PEER), the Multidisciplinary Center for Earthquake Engineering Research (MCEER), and the Mid-America Earthquake Center (MAE)—and has expanded to more than 100 institutions around the world. UCIST has worked to enhance undergraduate education by procuring instructional bench-scale shake tables, developing relevant curricula, and disseminating these tools to other institutions. Additionally, UCIST encourages outreach activities to K–12 students and the general public and provides plentiful undergraduate research opportunities.
UCIST has partnered recently with the George E. Brown Network for Earthquake Engineering Simulation (NEES), a premier cyberenvironment project funded by the National Science Foundation (NSF). NEES provides an excellent opportunity to increase the number of students that UCIST can reach through its educational exercises and to develop a collaboratory in earthquake engineering education. In partnership with the nonprofit NEES Consortium, Inc. (NEESinc) UCIST will leverage the geographically distributed network of world-class experimental facilities, its connecting cyberinfrastructure, and its extended community of engineering and cross-disciplinary faculty from academic programs across the nation to provide undergraduates with exceptional learning opportunities. We at UCIST plan to employ the extensive array of cyberinfrastructure tools developed for NEES research to enhance the learning process at the undergraduate level. Most of these tools are opensource and are continually updated and improved.
Our vision is to develop a national collaboratory of benchscale earthquake engineering facilities that will engage a broad range of students by creating a series of shared laboratory exercises available for remote operation via the Internet. This educational collaboratory will leverage the cyberinfrastructure, coordination capabilities, and educational goals of the NEES initiative. Existing state-of-the-art cyberinfrastructure tools developed by NEESit (NEES Information Technology, http://it.nees.org), the technical support and development component of NEES, will be utilized for tele-operation and teleparticipation. Recently, tools have been developed for remote control (tele-operation) and the viewing and analysis of streaming data and video (teleparticipation) over the Internet for instructional shake tables. These capabilities have been incorporated into formal laboratory exercises, and in fall 2007 we will begin testing these exercises at several universities within the United States. Over the next couple years, we will develop additional exercises using these capabilities. Information on how to join this collaboratory is available at the end of this article.
The equipment used for these instructional materials consists of a Shaker IV system from Quanser Consulting (http://www.quanser.com). The bench-scale seismic simulator, shown in figure 1, has a 46 × 46-cm slip-table driven by a ball-screw mechanism with an operating frequency of 0–20Hz, a ±7.6-cm stroke and a peak acceleration ±1 g with an 11.3 kg payload. The Shaker IV interfaces with a PC through the Quanser Q8 board and is controlled with WinCon real-time software. This shake table is a powerful tool for high fidelity and controllable reproduction of seismic motions. Accelerometers are available for measuring the responses of the structure and recording the measurements. Data can also be streamed in real time to remote users for plotting and analysis. This equipment (available for $10,000–$25,000 depending on the components needed) is ideal for educational uses and has also widely been used for K–12 outreach, demonstrations, and small-scale research projects. A prior NSF-funded cooperative project to establish shake tables at universities across the country facilitated the dissemination of the proposed project to universities nationwide.
Several experiments that use this shake-table lab station are available on the UCIST Web site for downloading and implementation. Experiments consider structural dynamics, soil-structure interaction, bridge design, torsional responses of structures, etc. The Web site contains laboratory manuals for instructors and students, drawings for building experimental components, and sample data. These experiments have been used at institutions across the United States to educate undergraduate and graduate students in earthquake engineering topics. Users who may be interested in posting new experiments to share with the earthquake engineering community are welcome to contact the authors.
In addition, an Earthquake Engineering Module for K–12 education has been developed around the use of this shake-table lab station. The module contains a series of lessons that have been developed and refined over the course of several years. In principle, any of the “modules” could be used as a stand-alone, one-time lesson to supplement one specific academic area such as forces and vectors or building fundamentals. Alternatively, the full module could be used as a series of lessons over an 8–10 week period. Supplemental worksheets, learning activities, and presentations are included to provide opportunities for active learning. The final lesson involves a design project incorporating all of the materials learned within the module. Teams of students design and construct a balsa wood building. A scorecard is provided to encourage students to be creative and yet understand practical issues associated with construction and design. Ideally this module, presented as a whole or individually, will satisfy some of the educational requirements and standards of the K–12 classroom in which it is offered.
NEES cyberinfrastructure tools make it possible for earthquake engineering researchers to conduct hybrid experiments involving distributed testing of various components of a single structural system. Video and data can be transferred in real time to laboratories and users around the nation for analysis and simulation. These teleparticipation capabilities are being employed for educational uses by UCIST and for the development of a series of new educational exercises. These exercises will allow a broader set of students and institutions to access the shake tables for education and training and will facilitate national dissemination of real-time online laboratory experiments. Stateof- the-art laboratory experiences like these have not previously been available to undergraduates.
Tele-operation, e.g., remotely controlling the UCIST shake table using the NEES cyberinfrastructure, was first accomplished by Richard Christenson in December 2004. More recently, an expansion of this effort has been undertaken involving teleparticipation by adding functionality to stream data and video through existing cyberinfrastructure tools. The Shaker IV control PC (connected to the shake table) is configured as a server to receive commands. Commands to the shake table originate from the user though the graphical user interface running at the client (remote) end. The NEES Real-time Data Viewer (RDV) is then used to view the time-synchronized streaming video and data from any PC over the Internet. Figure 2 is a snapshot of the streaming video and data from the STII shake table displayed through RDV. Instructions for configuring and implementing these tools will be available on the UCIST Web site (http://ucist.cive.wustl.edu/) by fall 2007.
To date, one formal telepresence experiment has been conducted in a classroom setting. A freshman-level experiment has been developed to introduce earthquake engineering concepts through teleparticipation experiments utilizing the bench-scale shake table. The module consists of a series of eight lectures that introduces students to topics in structural engineering, mathematical modeling of dynamic behavior, MATLAB simulation tools, and NEES capabilities and research. Then the students use the teleparticipation tools to conduct an experiment with the shake table. A one-story (single-degree-of-freedom) structure with light inherent damping is used (see figure 3). An accelerometer is used to capture structural response data for a sinusoidal excitation. Video and data are observed and downloaded through RDV for analysis and comparisons to mathematical models. The module culminates with the preparation of a laboratory report. This experiment has been implemented at the University of Connecticut and Washington University in St. Louis. Evaluation of the tools is now underway, and the tools will be disseminated on the UCIST and NEES Web sites (http://ucist.cive.wustl.edu/ and http://www.nees.org/) in fall 2007.
A second tele-operation experiment for senior-level undergraduates is being developed and should be available in fall 2007 and subsequently disseminated through the UCIST Web site. Furthermore, an undergraduate structural design competition will be implemented with the instructional shake tables to encourage students to learn more about earthquake engineering and introduce them to the broader earthquake engineering community. Activities such as the well-recognized Steel Bridge and Concrete Canoe competitions by the American Society of Civil Engineers (ASCE) have long proven that these types of team-building exercises promote technical interaction and excitement in civil engineering among undergraduates while stimulating life-long learning. In this spirit, the networked shake tables provide a unique opportunity to engage civil engineering undergraduates by challenging them to design innovative model structures that will withstand strong ground motions.
Bench-scale shake-table lab stations provide a flexible tool on which to base educational exercises for students at all levels. Hands-on experiments and demonstrations provide tangible evidence of the dynamic behavior of structures, which improves student understanding and awareness. Training in the use of sensors is also an essential component of such exercises. NEES cyberinfrastructure tools, originally developed for advancing research efforts, are being adopted for educational use. Through a partnership with NEES, UCIST is extending its reach to students across the United States and potentially around the world.
Further information about UCIST, as well as educational modules, lab exercises, teleparticipation and tele-operation tools, and all documentation for these activities will be made available at http://cive.seas.wustl.edu/wusceel/ucist/. For more details on how to participate or partner with this educational collaboratory please contact the corresponding author.
Partial support for this project is provided by the National Science Foundation, DUE 0618605. Support for development of UCIST was provided by the NSF, DUE 9950340. Undergraduate research assistants involved in the development of these activities have been supported in part by the National Science Foundation Research Experiences for Undergraduates Program at Washington University (NSF Grant No. EEC–9820506). All of this support is gratefully acknowledged. Funding for the development of the Earthquake Engineering Module for K–12 Education has been provided in part by the NSF under Grant Nos. DGE–0138624, DGE–0538541, and CMS–0530737. Special thanks is also given to those teachers in the St. Louis area who have contributed to this research.
School of Engineering and Applied Science
Washington University in St. Louis
Campus Box 1130
St. Louis, Missouri 63130 USA
sdyke [at] seas.wustl.edu
Posted: 29 June 2007