PSI - Issue 44

Federico Germano et al. / Procedia Structural Integrity 44 (2023) 902–909 F. Germano et al./ Structural Integrity Procedia 00 (2022) 000 – 000

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MQTT Message Queue Telemetry Transport

Monitoring parameters is become more and more significant in the context of civil infrastructures structural health for various reasons. In Italy, where an impressive number of architectural heritage sites, in large part of territory, is subject to seismic risk, the topic is of unique relevance. This geographic peculiarity is coupled with several other reasons: • Architecture buildings are becoming increasingly complex and challenging for structural behaviour • Concrete ageing is heavily impacting the “booming economy age ” buildings , including a large portion of Italian bridges • Seismic territory, sea presence and increasing heavy weight vehicles are creating a combination of physical loads, corrosion and ground vibration level that is pretty unique in his distribution, yet every structure exhibits his own behaviour • The structure range is very variable: bridges, dams, towers, skyscrapers and historical buildings are all in focus • Traffic conditions are quickly evolving both in weight distribution and in number of vehicles; moreover, autonomous driving and automated brake systems are creating enhanced couplings of structure response with traffic pattern. The main benefit of a monitoring system of infrastructures, as communicated to the large public, is to allow reaction in time, before an accident occurs. Of course this high level requirement declinates into several sub-requirements, each one contributing to the main goal. A correct measurement system could allow engineers to evaluate, for instance: • Load conditions over the structure (traffic, train passages, wind, temperature, …) and their comparison with design data • Correlation and model updating of numerical, FEM simulations, particularly for dynamic behaviour (i.e. operational modal analysis) • Validation of new analysis techniques, for instance derived from machine learning, whose greatly benefit from real data samples to evolve and being proven, instead to relate their performance from overfitting numerical data • Detection and monitoring of known damages and flews overtime • Maintenance scheduling, facilitate inspections, prioritize intervention where choices are to be made • Status of the structure after an event, make quick and right decision in emergency cases The actual status of the monitoring technology currently installed widely is not always able to cope with such requirements, for several reasons leading to measurement constraint. I will try to summarize those in following headings. 1.1. Load assessment Load conditions are very often one of the main measurement application concerning structural monitoring. Some common examples are following: • Wind pattern is very common requested to be characterized for structure like bridges. Some areas have strong wind detected almost every day, acting as a “constant” force module over the structure; at the same time, wind is changing direction and turbulence condition, exciting pretty much every dynamical behaviour of the bridge. Wind characteristic are often measured through meteo station,