June 20, 2010
June 20, 2010
June 23, 2010
15.402.1 - 15.402.11
Development of a Geotechnical Earthquake Engineering Teaching Module Using an Instructional Shake Table Abstract Liquefaction, which is the loss of strength of supporting soil, is one of the major causes of destruction to permanent infrastructure (roads, buildings, and bridges). After being introduced to the concepts of compaction, permeability and effective stress in an introductory geotechnical engineering course, undergraduate students understand the basic concepts of liquefaction. In this research, an apparatus was built to provide hands-on experience to undergraduates to provide them with a greater understanding of the liquefaction mechanism, liquefaction induced damage to the built environment and the influence of various soil properties that trigger liquefaction. A geotechnical earthquake engineering teaching module was also developed for use with the apparatus. Subsequent experimentation indicates that the apparatus constructed in this research successfully demonstrated the mechanism of liquefaction, liquefaction induced damage and the influence of soil properties on the extent of the damage. The proposed experiments are repeatable and the teaching module can be included as one of the many geotechnical engineering laboratory experiments. These experiments will give students hands-on experience in sample preparation, instrument use and testing with various earthquake time histories.
Introduction Earthquakes threaten millions of lives and property in both the United States and abroad. The US Geological Survey (USGS) estimates that several million earthquakes occur throughout the world each year, although most go undetected because they hit remote areas or have very small magnitudes. On average, only 18 of these earthquakes occur at a magnitude of 7.0 or higher annually1. One of these for the year 2010, being the January 12, Haitian earthquake which claimed over 200,000 lives and left millions more homeless. Because earthquakes are impossible to predict, preventive measures to reduce earthquake induced damage are critical to ensuring infrastructure integrity after such events, as the Haitian quake all too graphically illustrates. Introducing civil engineering undergraduates to the concepts of earthquakes and discussing the impact of earthquake induced damage to the built environment is one method for showing students some of the preventative measures. Fortunately, teaching undergraduates about earthquakes and engaging them in discussions on the damage they can induce to the built environment is not a new concept. One example of a successful initiative is the University Consortium on Instructional Shake Tables (UCIST)2, the primary goal of which was to develop experiments that would provide undergraduates with a firm grounding in structural dynamics. Numerous teaching models that were used to achieve this goal are on the UCIST’s website3. However, though the UCIST provided detailed structural dynamic experiments, they did not provide soil dynamics experiments particularly those related to liquefaction induced damage to the built environment.
Liquefaction, which is the loss of strength of supporting soil, is one of the major factors contributing to severe damage to the built environment in various forms such as ground settlement and movement, slope failure, damage to buried utility lines. Figure 1 shows a photograph of liquefaction induced damage to structures after 1964 Niigata earthquake. There was no structural damage observed but the structures tilted and settled due to ground liquefaction. Since liquefaction can be an abstract concept to many students, it is usually
Ravichandran, N., & Machmer, B. (2010, June), Development Of A Geotechnical Earthquake Engineering Teaching Module Using An Instructional Shake Table Paper presented at 2010 Annual Conference & Exposition, Louisville, Kentucky. https://peer.asee.org/16013
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