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Buildings and manmade structures around the world are vulnerable to fire, terrorist attacks, subsidence, and natural disasters such as floods and earthquakes. It’s easy to see that collapsed buildings aren’t safe, but what about the ones that remain standing?
In these cases, schools, offices, hospitals, hotels and all other buildings must remain closed while structural engineers make an in-depth on-site structural analysis of any hidden damage. The time-consuming and expensive nature of this process is compounded by a shortage of experienced inspectors.
But it is possible for the factors that lead to failure to be measured. Structural Health Monitoring (SHM) is an innovative approach – using cutting-edge sensors, data acquisition systems, wireless technologies and other advances – to monitor buildings’ structural safety, integrity and performance. Although still underused, SHM actively avoids disaster by detecting damage early – potentially saving lives as well as the structure itself.
The EU-funded RECONASS project combined SHM with disaster management tools to prototype a complete information system designed to assess the status of buildings both during normal, everyday operations and after extraordinary events. Its primary goal has been to provide stakeholders with an accurate, up-to-date and near real time assessment of a building’s structural and non-structural status.
‘When RECONASS is monitoring a building, relief organisations can begin restoration efforts at a much earlier date,’ says project coordinator Angelos Amditis of the Institute of Communication & Computer Systems in Greece. ‘Emergency response crews will receive critical information promptly, disaster costs are reduced by preventing monitored structures from collapsing, and preparedness may also be enhanced, as the RECONASS system can also act as simulation software.’
Drones, sensors, and satellites
In the RECONASS system, a network of sensors provides detailed information about movement and stress within the building structure. Several types of sensors embedded in or attached to the building detect the presence, location, severity and consequence of damage.
Temperature and external imaging data are also collected by drones and satellites and transmitted to a central monitoring hub. The system reports on the structural health of the building via a 3D model, allowing damage to be clearly visualised and animated.
The system features:
- A compact and highly energy efficient local positioning system which cooperates with strategically placed sensors.
- A secure, intelligent and resilient communication module to gather and centralise all sensor data.
- A remote sensing framework of airborne drones and space satellites to scan the building’s exterior and compare this to sensor data.
- A 3D visualisation of the building loaded with its structural status, including external data such as meteorological data and newsfeeds.
The RECONASS team successfully evaluated and benchmarked their concept in a live experiment with explosions designed to replicate a real-world scenario. They placed 400 kg of TNT on the inside and 16 kg on the outside of a three-storey reinforced concrete building fitted with the system of sensors and other prototype technologies.
Building resilience
The team hopes their prototype will help drive the expansion of smart structural health management for buildings throughout the EU and further afield, ultimately helping to build society’s resilience to both manmade and natural disasters.
‘Further research is required in advanced and mobile/cloud processing technologies, and in the cost-effectiveness and miniaturisation of sensors, communication modules and mobile communication units,’ says Amditis. ‘This can all be facilitated by disseminating RECONASS’ results as well as by continuing the national and EU funding programmes related to SHM technologies.’.