Past, Present, and Future of Engineering under Uncertainty: Safety Assessment and Management

The author’s perspective of engineering under uncertainty is presented. In the first part of this chapter, past, present, and future trends of reliability assessment methods, applicable to many branches of engineering, are presented. The discussions cover the cases for both explicit and implicit limit state functions. Finite element-based reliability evaluation methods for large structures satisfying underlying physics are emphasized. The necessity of estimating risks for both strength and serviceability limit states is documented. Concept of several energy dissipation mechanisms recently introduced to improve performance and reduce risk during seismic excitations can be explicitly incorporated in the formulation. Reliability evaluation of very large structures requiring over several hours of continuous running of a computer for one deterministic evaluation is briefly presented. Since major sources of uncertainty cannot be completely eliminated from the analysis and design of an engineering system, the risk needs to be managed appropriately. Risk management in the context of decision analysis framework is also briefly presented. In discussing future directions, the use of artificial neural networks and soft computing, incorporation of cognitive sources of uncertainty, developing necessary computer programs, and education-related issues are discussed.