Wilson Tang Lecture
Geotechnical probability: From FOSM to RFEM
Professor of Civil Engineering at the Colorado School of Mines
Abstract
For geotechnical professionals, the words "risk" and "probability" should not be confused, since risk is the probability of design failure weighted by its consequences. An obvious implication of this definition is that if the consequences of a failure are serious in terms of loss of life and/or cost to infrastructure, the allowable or target probability of failure for design must be commensurately low. Conversely, if the consequences of failure are relatively less important, a higher allowable or target probability for design can be allowed. Risk is therefore inextricably linked to quantitative probability estimates. Geotechnical engineers have a toolbox of methods available for estimating probability, ranging from hand calculation methods such as the First Order Second Moment (FOSM) method, to mildly computational method such as the First Order Reliability Method (FORM) to intensively computational numerical methods such as the Random Finite Element Method (RFEM). This paper reviews these methods, offers an alternative approach to FORM, and highlights some of their characteristics that can be taken into account when applying them to probabilistic geotechnical applications.
Biography
D. Vaughan Griffiths PhD, DSc, PE, D.GE, C.Eng, FICE, Dist.M.ASCE is a Professor of Civil Engineering at the Colorado School of Mines. His research interests lie in application of finite element and risk assessment methodologies in geotechnical engineering, and his papers on slope stability analysis are among the most highly cited in the geotechnical engineering literature. He is the co-author of three textbooks that have gone into multiple and foreign language editions on "Programming the Finite Element Method", "Risk Assessment in Geotechnical Engineering" and "Numerical Methods for Engineers". He gives regular short-courses on Risk Assessment for practitioners, with recent offerings in Australia, Canada, China, Colombia, New Zealand, Norway, Taiwan and the USA. Professor Griffiths is a past-editor of the journals Computers and Geotechnics, Journal of Geotechnical and Geoenvironmental Engineering and Géotechnique. In 2017, he was named the Cross-Canada Lecturer by the Canadian Geotechnical Society, and the same year received the H. Bolton Seed Medal from the ASCE/Geo-Institute. He served on the Board of Direction of ASCE from 2010-2013 as the Region 7 Director, and was inducted as a Distinguished Member of the ASCE in 2020. In 2021 he was the TH Wu Distinguished Lecturer.
Professor of Civil Engineering at the Colorado School of Mines
Abstract
For geotechnical professionals, the words "risk" and "probability" should not be confused, since risk is the probability of design failure weighted by its consequences. An obvious implication of this definition is that if the consequences of a failure are serious in terms of loss of life and/or cost to infrastructure, the allowable or target probability of failure for design must be commensurately low. Conversely, if the consequences of failure are relatively less important, a higher allowable or target probability for design can be allowed. Risk is therefore inextricably linked to quantitative probability estimates. Geotechnical engineers have a toolbox of methods available for estimating probability, ranging from hand calculation methods such as the First Order Second Moment (FOSM) method, to mildly computational method such as the First Order Reliability Method (FORM) to intensively computational numerical methods such as the Random Finite Element Method (RFEM). This paper reviews these methods, offers an alternative approach to FORM, and highlights some of their characteristics that can be taken into account when applying them to probabilistic geotechnical applications.
Biography
D. Vaughan Griffiths PhD, DSc, PE, D.GE, C.Eng, FICE, Dist.M.ASCE is a Professor of Civil Engineering at the Colorado School of Mines. His research interests lie in application of finite element and risk assessment methodologies in geotechnical engineering, and his papers on slope stability analysis are among the most highly cited in the geotechnical engineering literature. He is the co-author of three textbooks that have gone into multiple and foreign language editions on "Programming the Finite Element Method", "Risk Assessment in Geotechnical Engineering" and "Numerical Methods for Engineers". He gives regular short-courses on Risk Assessment for practitioners, with recent offerings in Australia, Canada, China, Colombia, New Zealand, Norway, Taiwan and the USA. Professor Griffiths is a past-editor of the journals Computers and Geotechnics, Journal of Geotechnical and Geoenvironmental Engineering and Géotechnique. In 2017, he was named the Cross-Canada Lecturer by the Canadian Geotechnical Society, and the same year received the H. Bolton Seed Medal from the ASCE/Geo-Institute. He served on the Board of Direction of ASCE from 2010-2013 as the Region 7 Director, and was inducted as a Distinguished Member of the ASCE in 2020. In 2021 he was the TH Wu Distinguished Lecturer.
