  The difficulty in quantifying the benefit of Structural Health Monitoring
(SHM) for decision support is one of the bottlenecks to an extensive adoption
of SHM on real-world structures. In this paper, we present a framework for such
a quantification of the value of vibration-based SHM, which can be flexibly
applied to different use cases. These cover SHM-based decisions at different
time scales, from near-real time diagnostics to the prognosis of slowly
evolving deterioration processes over the lifetime of a structure. The
framework includes an advanced model of the SHM system. It employs a Bayesian
filter for the tasks of sequential joint deterioration state-parameter
estimation and structural reliability updating, using continuously identified
modal and intermittent visual inspection data. It also includes a realistic
model of the inspection and maintenance decisions throughout the structural
life-cycle. On this basis, the Value of SHM is quantified by the difference in
expected total life-cycle costs with and without the SHM. We investigate the
framework through application on a numerical model of a two-span bridge system,
subjected to gradual and shock deterioration, as well as to changing
environmental conditions, over its lifetime. The results show that this
framework can be used as an a-priori decision support tool to inform the
decision on whether or not to install a vibration-based SHM system on a
structure, for a wide range of SHM use cases.
