The Vienna Terzaghi Lecture is the highlight of the Austrian Geotechnical Conference that takes place every two years. Karl Terzaghi (1883-1963) was professor at the Technical University of Vienna from 1929 to 1938. In 1924 he completed the first published book with the title Soil Mechanics in German (Erdbaumechanik). He is recognized as the founder of modern Soil Mechanics and was the first president of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE). Giroud delivered the Vienna Terzaghi Lecture on February 21, 2005, and then presented it at the following locations: Atlanta, USA, November 15, 2005; Hong Kong, China, April 11, 2006; Yokohama, Japan, September 18, 2006; Bucharest, Romania, June 7, 2007. Giroud’s Vienna Terzaghi Lecture is accompanied by a paper published in the proceedings of the 5th Austrian Geotechnical Conference.

Abstract

The lecture presents in detail two cases of failures and two cases of successes related to structures incorporating geosynthetics. Analyses of these cases are presented and lessons learned are discussed. An important lesson learned is that engineering problems, whether they are related to failures or successful applications, can always be solved by following a rational approach, generally including theoretical analyses. In contrast, common sense or “engineering judgment”, used without the support of a rational approach, can be misleading, as illustrated by examples. In other words, this lecture is consistent with the “theory and practice” approach promoted by Terzaghi. Another lesson learned is that geosynthetics engineering is an integral part of both geotechnical and civil engineering, which results in fruitful technology transfer. Also, failures and successes are put into perspective: it is shown that failures represent a very small fraction of the structures incorporating geosynthetics. To illustrate this point, the lecture includes a survey of the most important applications of geosynthetics using spectacular photographs of structures incorporating geosynthetics constructed in various countries. Even though innovative methods are presented, the lecture is presented in a simple and entertaining way and is accessible to all civil engineers.