ABSTRACT
The ASCE recognizes that civil engineering practice is falling short of delivering products and services to satisfy the societal needs for transportation, water, power and energy delivery, and sustainable constructed systems (Committee Report, 2005). Paradigms such as performance-based civil engineering, health-monitoring and integrated asset management offer great improvements in the engineering and managing the constructed environment. However, there is one major knowledge barrier standing in the way of effectively leveraging such innovative paradigms, this is a lack of our ability to reliably predict the mechanical characteristics, loading environment and behavior of constructed systems at various critical limit states of performance. The writers’ experience and a recently conducted in-depth literature survey has reiterated what many civil engineers have learned through anecdote, i.e. the epistemic uncertainty that governs constructed systems and their interactions with nature and human systems makes it very difficult to develop complete scenarios involving their performance and to predict their reliability. Epistemic uncertainty introduces a significant risk in any decision related to the constructed environment that most engineers and managers are often unaware of, especially when we try to design for sustainability and project conditions and performance of a system into the distant future. Unfortunately, no modern design, operation or maintenance code for constructed systems, while many of these are explicitly framed by the structural reliability theory, recognizes that epistemic uncertainty may render any stipulation of (time-based) structural system reliability greatly suspect. In the case of performance in the operational, serviceability, durability and security limit-states, epistemic uncertainty especially stands as a major barrier to meaningful management.
