Simplifications for Decision-Making on Bridge Portfolios: Current Developments and Future Research Directions

Infrastructure managers must make decisions that ensure the safe and efficient operation of their networks under conditions of limited resources and high uncertainty. However, planning large-scale interventions presents multiple challenges. In bridge management, for example, current planning practices focus on the progression of bridge deterioration and the effects of operational loads. However, other alarming conditions arising from extreme load cases, such as seismic, hydraulic, or accidental events, are not formally integrated into the decision-making process. This shortcoming is largely due to the difficulty of representing uncertainty in extreme load cases, particularly when analysing large asset portfolios. Consequently, there is a growing demand for simplified yet systematic and reliable approaches to prioritizing interventions in large bridge portfolios that account for a wide range of potential load conditions and enable managers to respond rapidly when necessary. This paper reviews a selection of existing approaches that simplify the evaluation of bridge portfolios. It also analyses the use of fault tree analysis to systematically evaluate multiple extreme load cases that may lead to bridge failure. The results suggest that, despite numerous efforts to support bridge decision-making, a gap remains between current bridge management practices and research advances. Specifically, this relates to providing a bridge manager with a structured overview of potential bridge failure scenarios when assessing large bridge inventories. A bridge example is used to illustrate the systematic use of fault-tree structures for assessing bridges. Furthermore, this paper includes a brief discussion of future research directions in large-scale bridge management.

Keywords: Bridge management, bridge portfolios, fault tree analysis, risk assessment, systematic assessment.