Practical reliability analysis and design by Monte Carlo Simulation in spreadsheet

Uncertainties are unavoidable in geotechnical engineering, and they arise from loads, geotechnical properties, calculation models, and so on (e.g., Baecher and Christian, 2003; Ang and Tang, 2007). To deal rationally with these uncertainties in geotechnical analysis and design, several reliability (probability)-based analysis and design approaches have been developed for geotechnical structures (e.g., Tang et al., 1976; Christian et al., 1994; Phoon et al., 1995; Low and Tang, 1997; El-Ramly et al., 2005; Wang, 2011; Wang et al., 2011a,b). Although these efforts significantly facilitate the understanding and application of geotechnical reliability-based approaches, practicing engineers are reluctant to adopt them in geotechnical practice, at least, due to two reasons: (1) the training of geotechnical practitioners in probability and statistics is often limited and, hence, they feel less comfortable dealing with probabilistic modeling than working with deterministic modeling (El-Ramly et al., 2002); and (2) the reliability algorithms are often mathematically and computationally sophisticated and become a major hurdle for geotechnical practitioners when using geotechnical reliability-based approaches. It is, therefore, worthwhile for geotechnical practitioners to have a practical and conceptually simple framework that is directly extended from conventional deterministic modeling and removes the hurdle of reliability algorithms.