Submitted to the 7th US National Conference on Earthquake Engineering, EERI, Boston, MA, July 21–25, 2002.
ADVANCING EARTHQUAKE ENGINEERING EDUCATION THROUGH A COOPERATIVE EFFORT BASED ON INSTRUCTIONAL SHAKE TABLES S.J. Dyke1, S.M. Johnson2, R.T. Ranf,3 J.M. Caicedo4, and M. Soto-Fournier5 ABSTRACT The University Consortium of Instructional Shake Tables (UCIST) was formed in 1998 to enhance undergraduate and graduate education in earthquake engineering (see: http://ucist.cive.wustl.edu/). This educational consortium, a joint effort between several universities associated with the three national earthquake centers, has endeavored to enhance the education of civil engineering undergraduates through the procurement of instructional shake tables and the development of corresponding curricula to be used at the undergraduate level. Additionally, outreach activities and undergraduate research opportunities are encouraged with of this equipment. The consortium is headquartered at Washington University in St. Louis. This paper will discuss the accomplishments of the UCIST project to date. Specifically, achievements relevant to the overall goal of incorporating structural dynamics and control into the undergraduate civil engineering curriculum will be described, including the development of “hands-on” experiments, implementation of the equipment for undergraduate research, as well as relevant outreach efforts and undergraduate research opportunities. Introduction Although considering the dynamic behavior of these structures is of significant importance in modern structural design worldwide, undergraduate civil engineering students do not often have an opportunity to develop an understanding of the ways these structures respond when acted upon by time-varying loads. Because structural engineers of the future will be expected to implement the latest techniques for minimizing damage to structures subjected to such loading conditions and incorporate their knowledge in the design process, there is a need for integrating this important topic into the undergraduate curriculum.
1 Associate Professor, Dept. of Civil Engrg., Washington Univ., St. Louis, MO, USA,
[email protected] 2 Grad. Res. Asst., Dept. of Civil Engrg., Massachusetts Inst. of Tech. (formerly Undergrad. Res. Asst. at Washington Univ.)
[email protected] 3 Undergrad. Res. Asst., Dept. of Civil Engrg., Washington Univ., St. Louis, MO, USA,
[email protected] 4 Doctoral Cand., Dept. of Civil Engrg., Washington Univ., St. Louis, MO, USA,
[email protected] 5 Undergrad. Res. Asst., Dept. of Civil Engrg., University of Memphis (formerly Undergrad. Res. Asst. at Washington Univ.)
Even at the undergraduate level, many concepts in dynamics such as natural frequencies and mode shapes can be clearly demonstrated through “hands-on” experiments. Shake tables have been used at several universities for educating students about earthquake engineering and structural dynamics (for example, Kukreti and Wallace, 1996, Dyke et al., 2000a,b; Dyke 1997, 2000). Instructional shake tables (at bench-scale) are ideal to provide students access to such “hands-on” experiments. At this scale, students can design and build model structures, modify their structures, observe structural responses, measure structural responses, and test soil dynamics. Based on this concept, the University Consortium on Instructional Shake Tables (UCIST) was formed to strategically integrate earthquake engineering and structural dynamics into the undergraduate civil engineering curriculum. UCIST is a consortium of twenty three universities associated with the three national earthquake engineering centers – the Pacific Earthquake Engineering Research Center (PEER), the Multidisciplinary Center for Earthquake Engineering Research (MCEER), and the Mid-America Earthquake Center (MAE). This cooperative effort is expected to have a significant impact on the future direction of civil engineering education and serve as a future model for educational efforts. We anticipate that this nationwide effort will result in widespread adoption of this approach by civil engineering educators. As an indication of the potential of this program, over 40 universities (including several beyond the original 23) have obtained these shake tables since the UCIST was formed. Constantly evolving technologies such as the internet continue to reveal exciting avenues of communication and outreach that would have been unthinkable several years ago. The internet has made the field of earthquake engineering more accessible to both the public and the academic worlds. The experiments and curricular materials are freely available on the internet at the UCIST web site (http://ucist.cive.wustl.edu/). We aim to use electronic media and the internet to its full potential for the education and outreach activities. Combining the development of an inexpensive and highly-mobile bench-scale shake table with the medium of the internet, the University Consortium of Instructional Shake Tables (UCIST) has been able to use an integrated approach to teaching earthquake engineering with a civil engineering focus. All institutions are welcome to join the consortium. The only expectation is that the integrate UCIST experiments into their curriculum. All members are encouraged to submit experiments and projects developed for the equipment to the web site, so that other institutions can benefit from their experiences. The UCIST consortium has made substantial progress since its inception in 1998. This paper will summarize UCIST activities to date. The universities that compose the consortium have each purchased an instructional shake table lab station. Several tutorials, experiments and videos have been developed, and several more are in progress. Each university is also integrating at least three experiments into their undergraduate curriculum. Exposure to these topics early in a student's education can also engender interest in relevant research by the student. To augment the classroom activities, the UCIST equipment is available for undergraduate research experiences and nationwide contests involving design problems. This paper will focus on tutorials and projects that are already completed. These experiments and projects are available for download from the UCIST web site, and include both student and instructor manuals as well as necessary supporting material to reproduce the experiment. Several additional institutions have been involved in public outreach activities, and some of these will be briefly described herein.
Strategic Objectives of the UCIST The primary goal of the UCIST program is to instruct undergraduate students in concepts in structural dynamics, earthquake resistant design, geotechnical engineering, and more generally, in topics related to earthquake engineering. This goal is being achieved primarily through the introduction of experiments in earthquake engineering throughout the civil engineering undergraduate curriculum. The experiments focus on the use of “hands-on” seismic simulation experiments which offer students opportunities to operate the shake table, excite scaled models of various civil engineering structures (e.g., buildings, bridges, towers, etc.) with typical earthquake loads, learn basic concepts in structural dynamics, and utilize sensors to measure responses of the structures. Experiments are being developed for students at all levels – from freshman level introductory courses through senior/graduate level courses. The basic strategy behind the program described herein is to work collaboratively to achieve the project objectives, resulting in a well-rounded series of experiments that are geared for undergraduate students at all levels. The specific objectives of these activities are: i) to develop an understanding and an intuition regarding the Primary PrimaryActivities Activities dynamic nature of structures in undergraduate students; ii) to reinforce theoretical concepts through the use of Classroom Experiments “hands-on” laboratory experiments; iii) to provide expeVideos of Experiments rience in the use of modern engineering tools including Student Competitions sensors, actuators, and data acquisition/analysis equipCD-ROM of Experiments ment; iv) to provide non-engineering students with exposure to the potential consequences of earthquakes Secondary SecondaryActivities Activities and the dynamic behavior of civil engineering structures; v) to provide exposure to emerging technologies Undergrad. Research Projects and modern methods in seismic resistant design; and vi) Public and K-12 Outreach to improve technical communication abilities through written reports and oral presentations. These objectives Figure 1. UCIST activities. are being achieved through the development of a series of illustrative structural dynamics experiments and videos, and the integration of these experiments into the undergraduate curriculum. Furthermore, experiments are being developed for non-engineering students that will benefit from such exposure (e.g. architects and geo-scientists). Additional activities include plans for developing nationwide competitions in earthquake resistant design as well as research opportunities for undergraduate and graduate students. Information on the use of the instructional shake tables, updates for the software used to drive the table, algorithms and Simulink models developed for the tables, as well as published papers by UCIST members on structural dynamics topics are also available on-line at the UCIST web site. Instructional Shake Table Lab Station In June of 1998, a task force was formed with representatives from each center to develop a strategy to achieve this goal, identify equipment specifications, contact vendors to develop benchscale shake tables, and select the equipment to purchase. Three vendors participated in developing prototype units and bidding on the project. The bench scale shaking table selected by the UCIST
Task Force is produced by Quanser Consulting, Inc1. This instrument, shown in Figure 2, consists of a 18”x18” aluminum plate, which slides on high precision linear bearings and is driven by a Kollmorgan Silverline Model H-344-H-0600 electric motor fitted with a 1000 LPR IP 40 encoder. The earthquake simulator uses unit gain displacement feedback, and control is achieved using a MultiQ board. The MultiQ board is a general purpose data acquisition and control board which has 8 single ended analog inputs, 8 analog outputs, 16 bits of digital input, 16 bits of digital outputs, 3 programmable timers and up to 8 encoder inputs decoded in quadrature. The operational range of the simulator is 0–20 Hz. The capabilities of the shake table are summarized in Table 1. The shake table is controlled by a Pentium computer using Wincon software. The package comes with several historical earthquake records. Time and amplitude scaling is readily implemented using the provided software. In addition to the shake table, the laboratory package purchased includes a two story test structure and three accelerometer to measure the excitation and system responses. The package also includes a stand-alone function generator for off-site demonstrations. The complete package allows students to reproduce earthquakes, observe structural behavior, measure structural responses, and utilize sensors and modern computer control systems. Further the system purchased facilitates off-site demonstrations and other outreach activities. Outcomes to Date Several tutorials and sample experiments have been developed to get users started using the equipment. Additionally, many of the individual experiments have been completed and submitted to the web site. These are available for downloading to interested parties. This section will summarize the results to date. Tutorials and Sample Experiments
To accelerate the learning curve associated with using this equipment, several projects and manuals have been developed for implementation with the shake table. The manuals were written to provide as a guide for conducting the experiments that were produced, as well as to allow the
Table 1: Shake table capabilities. Specification Design Payload Peak Acceleration Operational Frequency Range Peak Velocity Table Dimensions Stroke Weight of Shake Table
Value 25 lbf 1g 0-20 Hz 20 in/s 18” x 18” 6” (+/- 3”) ~
