Quantifying the value of seismic structural health monitoring of buildings Piotr OMENZETTER 1 , Maria Pina LIMONGELLI 2 , Ufuk YAZGAN 3 1 The LRF Centre for Safety and Reliability Engineering, The University of Aberdeen, AB24 3UE, Aberdeen, UK piotr.omenzetter@abdn.ac.uk 2 Politecnico di Milano, Milan, Italy mariagiuseppina.limongelli@polimi.it 3 Istanbul Technical University, Istanbul, Turkey ufukyazgan@itu.edu.tr Abstract The decision to adopt a monitoring system for a structure should be based on sound appraisal of the expected economic benefits of such decisions. These benefits can be quantified in terms of the reduction of the risks posed by the failure of the structure versus the cost of monitoring. This paper discusses a framework for rationalising the adoption of monitoring for buildings subjected to seismic risks. The approach adopted is that of the pre- posterior decision analysis. Methods for automatic damage detection and joint utilisation of monitoring and visual inspection data are considered from a point of view of how they can be used in the pre-posterior analysis. Two short numerical examples are included to illustrate the proposed conceptual developments. Keywords: Pre-posterior analysis, Seismic monitoring, Value of health monitoring. 1. INTRODUCTION Structural health monitoring (SHM) techniques have now been a subject of extensive research and development for several decades. These efforts have led to significant progress in both hardware and software. Yet, the extent of adoption of the resulting technologies by different industries remains somehow underwhelming. One reason for this state of affairs can be that economic benefits of investing in SHM systems have rarely been quantified. Thus, various assertions are made about the usefulness of SHM but hard financial evidence is lacking. This paper contributes to addressing this gap in the current engineering practice by proposing a way of quantifying the value of SHM for buildings at risk from seismic damage using a pre-posterior decision analysis framework. Integrating automatic damage detection and visual inspections with the framework are also discussed. An SHM system installed in a building cannot prevent seismic damage as such, but the types of seismic risk which it can help to reduce are related to the consequences of incorrect post-event decisions. For example, if the building sustains inconspicuous damage in the main shock, but people and valuable content are not evacuated, casualties and significant economic losses may ensue if aftershocks lead to further damage and partial or total collapse. On the other hand, evacuating a building which is structurally sound will entail unnecessary financial losses due to business and occupancy interruption. To manage such risks requires choosing between several competing alternatives. These include ‘do nothing’, invest in different types of SHM systems with varying performance characteristics, invest in enhanced pre/post-earthquake visual inspections (e.g. similar to San Francisco’s Building Occupancy Resumption Programme [1]), invest in seismic retrofit, and others; some choices may be combinations of the aforementioned. All such choices bring certain benefits but come at a cost; furthermore, the benefits and cost cannot usually be quantified purely deterministically. 2. PRE-POSTERIOR ANALYSIS FOR QUANTIFYING VALUE OF SEISMIC SHM Suppose the stakeholders in the building are to decide if they want to adopt a monitoring system that will detect damage to the building struck by a strong earthquake. Depending on