Quantifying the benefit of SHM: can the VoI be negative?

Abstract

The benefit of Structural Health Monitoring (SHM) can be properly quantified using the concept of Value of Information (VoI), i.e. the difference between the utilities of operating the structure with and without the monitoring system. In calculating the VoI, a commonly understood assumption is that all decisions concerning system installation and operation are taken by the same rational agent. In the real world, the individual who decides on buying a monitoring system, the owner, is often not the same individual, the manager, who will use it, and they may behave differently because of their different risk aversion. We demonstrate that in a decision-making process where the two individuals involved share exactly the same information, but behave differently, the VoI can be negative. Indeed, even if the two agents have an agreement a priori, due to their different behaviors, their optimal actions can diverge after the installation of the monitoring system. This scenario could generate a negative Vol from the owners perspective. In this work, we propose a qualitative and quantitative formulation to evaluate when and under which circumstances the VoI can be negative, if the owner differs from the manager with respect to their risk prioritization. Moreover, we apply this formulation on a real-life case study concerning the Streicker Bridge (Princeton, NJ). The results demonstrate that when the owner, because of the managers different behaviour, is forced to undertake an action he would not chose, his VoI becomes negative, i.e. it is not convenient for him to install the monitoring system. This framework aims to help the owner in quantifying the money saved by entrusting the evaluation of the state of the structure to the monitoring system, even if the managers behavior toward risk is different from the owners own, and so are his management decisions.